# Situations to Avoid--The Safety Thread



## Lou (Nov 23, 2008)

As refiners, we use potentially dangerous chemicals and equipment on a frequent basis. Safety usually comes with experience but so too can complacency. It is my intention that this thread will help to educate our users and fellow refiners about what not to do in the laboratory and about how hazardous situations develop, and also some commonsense on what to do should you find yourself in a predicament. 

In the scope of this thread:


We will discuss problems and remedies.
We will discuss various situations and conditions to avoid.
We will cover proper chemical technique: materials compatibility, problems in scaling up reactions, handling chemicals safety, lab hygiene.
We will touch on waste disposal.
Basically, this will be what not to mix together, where and how to work in refining, and how to be responsible to yourself, your neighbors, and the environment. We will also touch on the basics of what to do if something does go wrong, but most our efforts are on _prevention_.

This will be a work in progress (I will continually update as more things come to mind) and I greatly welcome any valid contributions that members here may make. This is a serious thread about a serious issue that we all need to take note of and ensure safe refining practices. As such, posts are expected to remain on topic with information organized compactly. Thoughts and comments about this thread are welcome, but I will move them from here to a dedicated thread. I think this thread has been a long time coming. Hopefully we'll all help each other to avoid problems.


*
Our maxim is: Forewarned is forearmed. *


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## lazersteve (Nov 23, 2008)

Excellent thread idea Lou,

I'll start it off with a really basic one.

Never add water to concentrated acids. 

Always add acid to water. 

Adding water to concentrated acids, especially sulfuric acid, will cause the acid to sputter and spit. The violent reaction produces lots of heat very fast and the randomly flying acid can cause serious damage to your eyes, skin, clothes, and property.

On the same lines of sulfuric acid, exercise extreme caution when working with concentrated sulfuric acid. 

Never handle hot sulfuric acid until it cools. 

When handling concentrated sulfuric acid always wear proper safety gear including gloves, goggles, and an apron at a minimum. 

Do not fill beaker of concentrated acid to the brim as the liquid is easier to spill.

Do not breath the white fumes that form from hot concentrated sulfuric acid.

Keep a neutralizing agent handy (baking soda) in case of spills.

Work in a clean and clear area.

Don't eat or drink when working with sulfuric acid.

Always read the MSDS of any and all chemicals and the possible reaction products BEFORE working with any chemicals.

Be prepared for the worst case scenario before you begin your reaction.

Steve


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## qst42know (Nov 23, 2008)

I would think a spill kit would be worth the time and effort to put together for any size refining operation. 

Working on cardboard as Steve does not only absorbs drips and small spills but also prevents scratching or bumping your glass ware. 

A roll of paper towels are handy for the little stuff, but absorbent mats and socks rated for acids aren't cheap but could prove to be invaluable if the need arose. Many of these absorbent products are low ash and although a big project your values can be recovered. Cat liter as a last choice but better than nothing when you need it.

Enough baking soda or soda ash for the scale of your processing should be close at hand. This could be as small as a box of baking soda or several 50# bags of soda ash.

Now I work outdoors and keep the water hose on and near where I work. That serves as an eye or body wash should the need arise. If you don't have a water source very nearby you should seriously consider getting one or at least a couple 5 gallon buckets full of clean water with lids that fit but don't lock. Cut the locking tabs off if you have to.

Storing your acids (new or used) in plastic storage boxes provides secondary containment should one of those bottles or jugs fail. All my new acids, active solutions, and spent wastes in beakers bottles or buckets are placed in storage containers just in case.

Be safe everyone.


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## Lou (Nov 25, 2008)

Here is a brief list of things that are incompatible with each other:

Aqueous ammonia and free halogens. 
This means NH3 and F2, Cl2, Br2, and I2.
In particular, the combination of ammonia and chlorine or ammonia and iodine. Both of those form highly reactive and highly unstable explosives, NCl3 and NI3 which can explode with the slightest agitation.

NCl3 is far more stable than NI3 because it is a liquid and has no crystalline structure. In the case of nitrogen triiodide, if any is accidentally formed, extreme caution must be exercised in its disposal; if large quantities are formed, spontaneous detonation is probable, and the area should be cleared of persons and then property and authorities notified. The material is most sensitive when dry, and will detonate or deflagrate at the touch of a feather.

Nitrogen trichloride is an explosive yellow oil which slowly hydrolyzes in water--it can be decomposed by basic hydrolysis with sodium hydroxide. It is extremely irritating the eyes and mucosa. 

Silver nitrate should not be mixed with ammonia water because it can form "fulminating silver" especially upon long standing. See this thread for further details: http://goldrefiningforum.com/phpBB3/viewtopic.php?t=944&highlight=nitride

Soluble copper and silver compounds should not be added to oxalic acid solutions, as potentially explosive oxalate salts can form.


More coming soon...


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## goldnugget77 (May 29, 2009)

Hi folks 
Thanks for your helpful work
Lou
That link you posted is not working
As a matter of fact since the format of this forum changed a lot of the old links are not working
I hope someone will take the responsibility to fix these bad links 
Thanks 
God Bless You


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## goldnugget77 (May 29, 2009)

Also I am getting this message sometimes



> You do not have the required permissions to view the files attached to this post.



Here is one example


http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=325&hilit=getting+pure+gold+shining&start=60


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## Lou (May 29, 2009)

I'll check it out. Links worked for me, but it may be that one of the mods here already fixed them. Try them again. If it still doesn't work, it's probably another kink in our recent forum upgrade. I'll take the time to look into this more closely after I hear back from you.


I will be updating this thread. I intended to do a LOT more with it than I have.

EDIT: Thank you Steve for updating the links in this post, I appreciate you saving me the trouble!


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## goldnugget77 (May 29, 2009)

Hi Lou
The link is working now Thanks


If you go to this page

There is this message I notice that in other pages also
That is something that happened after the changes that were done to the site
You do not have the required permissions to view the files attached to this post.
Thanks again

viewtopic.php?f=49&t=325&hilit=getting+pure+gold+shining&start=60


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## Texas (Nov 13, 2010)

damn, I didn't know than mix of silver and ammonia gets a bomb! I have a jar of silver chloride near a bottle of ammonia....thanks by this post guys
Texas


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## Juan Manuel Arcos Frank (Nov 14, 2010)

Oh Yeah!!!!...BTW,never add ethyl alcohol to silver nitrate because an explosive compound is formed instantly.

Regards.

Manuel


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## Texas (Nov 14, 2010)

ethyl alcohol + silver nitrate= kaboom :shock: 
another one to my security sheet 
thanks Juan Manuel
Texas


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## publius (Nov 4, 2011)

My first post!

Never, ever add acid to cyanide solution. This will instantly produce cyanide gas! Cyanide gas is what is used to kill the condemned in gas chambers.

Always wear faceshields when working with acids and bases and if you expect an energetic reaction. You only have two eyes. Protect them.


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## Lobby (Apr 25, 2012)

Do you have safety eyewash stations / bottles? Can you find them with your eyes closed, which they will be if you get something in them. 

Your eyes are probably the most important part of your body. Take care of them.


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## ΩPhoenix (May 18, 2012)

Lou said:


> As refiners, we use potentially dangerous chemicals and equipment on a frequent basis. Safety usually comes with experience but so too can complacency. It is my intention that this thread will help to educate our users and fellow refiners about what not to do in the laboratory and about how hazardous situations develop, and also some commonsense on what to do should you find yourself in a predicament.
> 
> In the scope of this thread:
> 
> ...



Boy I am happy to be here in this forum.


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## racergold (Jun 6, 2012)

Regarding safety of other people, Im sure nobody would advocate refining in an apartment. And some houses these days seem very close together. My question is how much room would you need to do your refining without harming people next door? An acre? Five acres? I live in a house on five acres, (330 feetX660 feet). My house/garage/workshop is centrally located on the property. Is this enough room to safely refine small batches outside without the fumes/smoke getting to the neighbors? Would I have to shut down on windy days?


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## HENDRYK (Nov 29, 2012)

Thanks God i found this forum,All of you nice person,I know nothing about gold refining and chemical,i only have passion to find gold and willing to learn


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## FrugalRefiner (Nov 29, 2012)

Hendryk,

Welcome to the forum!

Everything you need to know to recover and refine precious metals can be found here on the forum. 

The first rule is to be safe in everything you do. Before you jump into any of the processes you see discussed here, be sure you understand the potential hazards and do everything you can to minimize the risks. It takes a lot of study but it's incredibly rewarding!

I strongly encourage all new members to follow the Guided Tour created by LazerSteve. It will provide an introduction to the forum and numerous valuable links. Be sure to follow the link to his web site as he has many outstanding videos, a collection of great reference documents, and he sells a lot of the supplies needed to get started including detailed instructional DVDs.

Second, download C.M. Hoke's book, _Refining Precious Metal Wastes_, from my signature line. You'll see this book mentioned repeatedly here on the forum for good reason. It is probably the best book ever written for the beginner who wants to learn refining. It is written in layman's terms and will provide a solid foundation that will help you understand everything you read here on the forum.

Finally, and I can't stess this enough, read EVERYTHING in the Safety section of the forum. No amount of precious metal is worth jeopardizing your health or the health of those around you.

Once you understand the basics you can start to try some small scale experiments. If there's something you don't understand or you get stuck, there will be someone here to help you.

Best of luck,
Dave

Edited to update link to Hoke's book.


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## scrappile (Nov 29, 2012)

Backup power for lighting and fumes, if you loose utility power at a critical time,...


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## Phil.elmer (Aug 5, 2013)

FrugalRefiner said:


> Hendryk,
> 
> Welcome to the forum!
> 
> ...



Thank you for the links dude, i will follow all of this. 
Im newbie here too.. ,


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## chlaurite (Aug 5, 2013)

I would like to second the "keep baking soda around" tip - I can't say it has saved my life, but it *has* prevented more than one minor acid burn on me. And don't wait when you realize you got something on you! Not sure? BICARB! It sure beats the "okay, my flesh has started bubbling up" test. :shock: 

On the flip side of that - Keep a jug of vinegar around as well. Lye causes MUCH nastier burns - Again, I've thankfully had nothing life-threatening, but because of the way it attacks flesh (saponifying your fats, basically turning YOU into soap), it can burn _much_ deeper than acids with a small amount.

And of course, rinse water. Gallons and gallons of rinse water, or even go so far as to install an emergency shower in your work-area. Personally, I keep the hose turned on and in close reach whenever I move anything involving more than a pipette full of liquid.

Surprised no one has mentioned kitty litter yet (the cheap clay kind). It doesn't "fix" anything, but it buys you a heck of a lot longer to figure out how to properly deal with that puddle of spilled acid rapidly spreading across the floor.


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## Geo (Aug 5, 2013)

i had a nitric acid burn a few months ago that nearly took the nail off. i didnt even realize i had gotten it on my finger. i picked up a watch glass without gloves on and the condensation ran under and around the nail. i though it was just water and thought no more about it until that evening when it felt as though something had been stuck under the nail to the quick. by then it was too late to neutralize and by the next day, the entire end of my finger was yellow. its healed now with no side effects but im aware of that particular danger now.


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## rickbb (Aug 6, 2013)

Check your safety gear often and before use. 

Sitting here with a nice blister on the end of my left ring finger due to an un-noticed hole in my "good" gloves.


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## Fabiank94 (Dec 2, 2013)

Even tho this is a obvious think never drink alcohol or do drugs before or meanwhile preparing for your refining. 
Allways be suspicious of strange smells it can be some leaking gas or anything else. 

*Things to have/do*
Have a working area with a good ventilation system.
Working clothes, Gloves, Glasses, leathercoat/coat, Respiratory Protection (face mask), phone nearby.
Labels to keep it all strutctured. (Remember to put the stuff back so you dont forget some acids that should not be mixed together at the same spot keep the seperated. 
Fire alarm at the working area + Phone. 
Never have something flamable like pillows etc in the working area. 
Never eat nor drink at the working area. 


Worst case scenario plan, ex eyewash, shower, foam fire extinguisher (if any fluid is on fire), a phone nearby with alarmcentrals phone number. 

That some stuff i came up with. I hope it helps 

Yours Sincerly Fabian


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## rickbb (Mar 11, 2014)

I just went through a major ice storm, knocked out the power for 3 days.

I had a batch of AP and a HCL soak of some boards under the fume hood at the time.

It was about 6 hours before I could get to the shop and set those containers outside some place safe.

Needless to say everything made of steel/iron in the shop had a light layer of rust on it. And everything else has that greasy grime feel to it from the deposit of the fumes.

Moral of the story, have a backup plan for when, (not IF), you lose power to your fume hood.


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## Digitaria (Mar 14, 2014)

Thanks for this - defo a few things here which I will employ. Newby signing off on this module.


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## Martijn (Nov 1, 2014)

racergold said:


> Regarding safety of other people, Im sure nobody would advocate refining in an apartment. And some houses these days seem very close together. My question is how much room would you need to do your refining without harming people next door? An acre? Five acres? I live in a house on five acres, (330 feetX660 feet). My house/garage/workshop is centrally located on the property. Is this enough room to safely refine small batches outside without the fumes/smoke getting to the neighbors? Would I have to shut down on windy days?



A bit late to react, but better late than never. The more wind, the more the produced gases get diluted in air and dispersed faster. So a soft breeze to no wind I would say is more dangerous. In these conditions the wind direction may also suddenly change, blowing towards you instead of away. And in low wind, gases can accumulate better to dangerous levels, slowly passing over a couple of propeties and maybe staying closer to the ground if heavier than air.

But if you have a runaway reaction (always consider the worst case scenario) could it produce a dense enough cloud to pose a danger to your neighbors or kids playing next door in the garden? You would have to know the estimated values produced, with wind dispersion models and compare to the maximum acceptable 'safe' level. It's quite a science, determining all the variables.
Considering the risks described on some of the MSDS's I would go for a more safe option to at least use some kind of condenser scrubber vessel and run the fumes trough an absorbing solution. 

be safe.

P.S. I'm thinking of categorizing risks and possible control measures for my setup for the different processes for silver refining and gold de-plating and refining, I will share it when it's completed or when I need additional input from y'all. 

I am going through the safety threads to pick your brains already. I really love this forum!!


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## Oak (Nov 2, 2014)

Well, thank you so much for this valuable safety information.
As a refining noob, information is power.
I am very glad I started my search for information in a forum such as this one.


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## FrugalRefiner (Nov 2, 2014)

Oak,

Welcome to the forum! 

You've made a great choice by starting in the Safety forum. From here, I'd like to suggest the Tips for Navigating and Posting on the Forum thread.

Dave


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## rickbb (Feb 9, 2016)

Small mishap the other day, kept small due to having a spill tub in place.

Had a 1L beaker of HCL on the hot plate warming it up to wash some precipitate and noticed a white ring of some kind of salt forming around the bottom of the beaker where it sits on the hot plate.

I don't remember any spillage or liquid running down the outside to hit the hot plate to create that kind of thing. So I turn the heat off, wait for it cool down, and then pickup the beaker to see what's going on.

Slosh, the beaker was cracked all the way around the bottom edge and when I picked it up the bottom stayed put so all I lifted up was the outside, now a hollow glass tube. 

All the hot HCL and the mud was now running down the hot plate and into my spill tub that I do all my stuff in. It's sized to fit the entire bottom of my fume hood just for that purpose.

Didn't get hot acid anywhere and saved all the mud. Was a mess to clean up, but no hazard or damage due to having that plastic tub to catch everything in.

Always think about spill management, it's not if, but when.


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## Smack (Feb 9, 2016)

I'll have to remember that one rick.

It's been about a week ago now, working in the lab for the day, everything was fine at first. Went to eat and got right back to it but made 3 simple minded bone head mistakes (procedurally speaking) and was so upset with myself I just packed it in and went home for the day. Didn't lose anything but could have and it made for more work getting everything back to where it should have been in the first place. Don't know why I lost focus....I don't remember any eye candy from when I went to eat.


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## IR0NHE4D (Apr 30, 2016)

Wow, guys!! Lots of great information and ideas! I'm extremely new to this hobby/activity, and safety is my primary concern. 

1) Has anyone tried creating a safety shield/working environment tailored to this activity? This sounds like a silly question, but my brain immediately went to a work area similar to the setup of a small-scale sand blaster. PPE is basically built into the chamber. Gloves, splash guard, etc. would be part of the setup. Probably wouldn't be too hard to include the fume hood and the spill containment bin. I was just thinking that one of those web cameras could be built into it as well, so you could look at whatever you needed (and as closely as needed) without the fear of losing sight, or more importantly, life. 

2) Having worked with some HAZMAT in previous jobs, I will definitely be labeling everything that I utilize as a storage container. I might even label each container I use in the process, i.e. sharpie on beakers and other containers. On this same line, I normally had the processes written out in a chart format. That way I could always see where I am in the process, and what chems were being utilized...just in case I brain farted. 

3) Is there a color chart? I don't like guess-work. When looking at chemical reactions, I like to have as much reference I can, so I know what is going on. Having easy references for before, during, and after a reaction, is a great reference. Might even be more important for a new guy like myself. If one doesn't exist, I'll keep y'all posted. 

4) Eye-wash/shower station idea. I'm thinking about setting up 2 5-gallon buckets filled with water as my emergency rinse station. I'm picturing an industrial eye-wash station where you pull the caps off and the water just comes jetting out. I'm not sure how it will work, but I'm thinking it would be great to put a shower head, or two, with a chain and valve. Same deal. Pull the chain and "water-on". 

5) Blower filtration. I guess this could have been part of the enclosure bullet, but would it be advisable to route the exhaust gases through some sort of bubbler to keep from just venting the gases? I was thinking that you could cap the reaction vessel and pipe the gas too a second container of neutral solution (water, or water + baking soda), to neutralize the gas. I would imagine that the same could be done with some sort of exhaust fan. Fans could be powered by DC, so a battery backup could be included.

I hope I didn't sound antagonistic in this post. It was just what popped through my brain. I loved the other suggestions and safety precautions I read already!!! Like I said, y'all are incredible for putting this type of forum together!

Any inputs are greatly appreciated. 

Be safe!


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## butcher (Apr 30, 2016)

IR0NHE4D,

Good thinking, keep it up. 
Great work by starting with the safety threads, I think you will do well in this field.

Yes there has been discussion of using an enclosed (gloved environment) similar to what you are referring to (no mention of camera that I remember), for some things it may work, although a fume hood is probably more useful (my opinion only).

Labeling and note taking are very important.
Keep a hazmat folder of your chemicals for reference, it can also be helpful and a good tool to have when the authorities knock your door down to see what you have been cooking up in your lab.

Color charts, some reactions we can have color charts as guides, pH and testing solutions, some reactions and precipitation, so using color as a guide in some ways is a helpful tool, then again we cannot always go by or trust colors, example take gold in solution a yellow color, well iron can also give a yellow color, take copper in solution a blue or green color, well iron can also give a green color.

Colors of solutions or other things can be very helpful in some ways, they are not always the best way to determine what a reaction contains, using colors alone you can easily be fooled, especially with so many different possible reactions, or conditions in some of the solutions we work with.
As you get further in your study you will gather a lot of information of colors and where they can be helpful...

You will find many references to colors, and charts on the forum, you will also find where many are fooled by colors...

Eye wash, is a good tool to have handy, ( a must have in my opinion), I use a water hose with a valve on the end. Were I can quickly get at it while blinded. I also keep a wash bottle handy for that dedicated purpose, and keep a bottle of eye wash saline handy... There are other things it is good idea to keep handy like a box baking soda for neutralizing acids (or other bases)... 

Capturing the gases, scrubbing them,or distilling them for reuse are also important for safety, and can be useful tools, not everything you generate is waste, it can also generate very useful byproducts...

Welcome to the forum


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## Topher_osAUrus (Apr 30, 2016)

Firstly, welcome to the forum ironhead. Butcher has given you great advice so far. And, by starting off in the safety section, you have undoubtedly earned a "kudos" from a great many of the long time members!

I will try to add a little bit (what i can)

1) fume hood is what you are looking for. There are excellent designs posted by a few great members -4metals, kurtak, phil, and others. Im sure adding a camera would be easy to do, should you be apt with building things.

2)yes, yes yes..label it all! Do as butcher suggested, print out every MSDS sheet for every chemical in your lab, put it in a bindwr that is easily accessible.

3)while there is no color chart, there is a great book that will give you a great abundance of information, rivaled only by this forums collective of info. Hoke - refining precious metals AND Hoke - testing precious metals. Both are held by everyone on this forum as the bible of refining. They are a great read (if you are a nerd like most of us, then itll be a real page Turner..if you aren't, then it may be a drag, but if you are in serious pursuit of this fiels, it is an absolute must read...it will help you get acquainted with the metals in solution, their color, procedures, etc... Its invaluable)

4)pretty solid idea.. I have an "oh no!"-station, that has a few gallon jugs of water.. A few boxes of baking soda... VERY dilute NaOH water, and VERY dilute HCl, as well as a little vinegar, bandaids, etc... Just stuff you hope to never need to use, but should have just in case..

5)Harold suggests having a filter in line on the fume hood to easily recover volatile losses that just went up in smoke or steam..he did refine commercially, but, his recovery from the filters bianually, was/is beyond impressive. Most fume hoods scrub the gasses before venting to atmosphere, and i believe they use sodium hydroxide for the most part, not sure how well baking soda would do if you are running processes in great volume.

Best of luck on this new found field of study for you.
Hope this may help

-topher, the-tickled-pink!


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## IR0NHE4D (May 1, 2016)

Many thanks to Topher and Butcher for the responses and the advice! 

After posting my comments, I did more research and eventually found the fume hood posts! Doh! I felt pretty stupid for re-asking the question. Great source of information, though. I did see a "hood", created from a storage tub. Had glove holes, and everything. Pretty cool idea. I may start with a variation of this. 

I have been reading in the Hoke book "Refining Precious Metal Wastes". Invaluable resource! My plan, is to walk through the book. I plan to do the testing activities and LEARN. The storage/hood should suffice for those "labs" listed for learning. I will have to look for the other book, "Testing Precious Metals". So far, I'm almost riveted. 

Great suggestion about the MSDS sheets. I had planned that for sure. Labeling is a must. You just cannot be too careful around these chems. There are some parts of life that you only get one shot, and I would hate to have a hobby do me in! Besides, I think my wife would be pissed if they only maimed me. haha!

I definitely agree that the color chart is not the end all reference. I just like to be familiar with the expected outcome, and any indications of success or failure are helpful.

I'm planning to start very slowly/small. Experiment and learn in a mostly controlled exercise. Then, I can scale up and enjoy myself. For the start, I will probably just be sure I'm outside, and provide some ventilation for more safety. I'll definitely be digging more into a scrubber setup before I get much more serious. I've seen a few examples that look pretty good, and moderately simple to build. 

I will likely just focus on Gold, Silver, Platinum, and Palladium. I'm guessing these are the big 4, but they are definitely easily found in similar equipment. 
I have found that there is a LOT of information in this forum, so I will continue digging.

Thanks again for all the help, comments, and the resources!!!

P.S.: After the Hoke book(s), I'll probably be getting the information from Lazersteve's site as well.


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## Topher_osAUrus (May 1, 2016)

Thats excellent to hear (read)!

For the scrubber, here are a few threads to get you going.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=9115&hilit=fume+scrubber

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=40&t=23159

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=40&t=19965&start=30

Once you have your AB-train / scrubber, there are a great many things you can do with it. Save your lungs, save the NOx gasses from nitric/AR reactions and make MORE nitric acid, and distill your homemade nitric, etc...

Miss Hoke's book -testing precious metals- is here on the forum
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=54&t=16555

If you cant get evac flasks for cheap (for the scrubber), some guys use pvc tubing.

If you can't get around to building one before your acquaintance experiments, using a watch glass will reflux the NOx gas pretty well. 

Diluting the acid also helps to keep the red cloud at bay, but, at the expense of time...you will get more mileage per ml, but it will take you longer to complete your dissolution.

When you have your stock pot started. Try to keep a couple solutions separate from one another. Like AR thats had gold precipitated, and nitric that has been used to dissolve silver (which you then cemented on copper).. That way, when you want to recycle or reuse the nitric, you have chloride free nitric, which will keep silver chloride out of your reaction (Hoke tends to treat silver chloride like its a nuisance...but, back in 1940, it wasnt worth much compared to now...and...silver chloride IS a nuisance..)

(I jist learned this from Lou, but) keep any solutions that had nickel in it away from sulfamic acid (which is used to expediently remove nitric from ar) as sulfamic is a chelator.

There are other things that I wanted to add, but, they are slipping my mind right now, and this reply is already ridiculously long. So, I will leave it at that!

-topher, the talkative

Edit to add: goldsilverpro's book, while i haven't purchased it yet, I have yet to read anything but excellent reviews from members here. They all say its great.

C.W. Ammen's book "recovery and refining of precious metals"

There are a lot more books out there, a section in the forum here has suggestions from other members.

I myself have downloaded quite a few, if you want me to send you the pdf's I have I will gladly do so. 

Im still waiting for Harold to write a book...he CLAIMS that nobody would want to read it, and it would just be a rewrite of hoke... But, I know he has much to add... Like anecdotes.. 20 years a commercial refiner, I'm sure theres a great deal of stories he hasn't posted on the forum...
(he DOES however have a pdf called "Harold_V refining karat gold" that I found online, which apparently was for a customer of his[if i recall correctly...a friend told me about it]..)

Id like to read a book by Butcher as well- he is very technical in his posts, and I love it

4metals and Lou as well, they are amazing with chemistry.
As is LazerSteve
Kurtak probably has enough experiences in his refining experience to fill a couple books

(they don't have books, but, click on their name...search their.posts...read them all)

Some of the best bits of this forum, are when our resident professionals are talking to one another in a thread... Its great.
I have multiple folders on my phone/laptop dedicated to such..also have about 6 notebooks full, and always keep a notebook or two on me... Always... 

The wife hates it, but, pshh..what does she know
:mrgreen: 

-topher, the thrice-over-talkative


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## upcyclist (May 3, 2016)

A great start!



IR0NHE4D said:


> I definitely agree that the color chart is not the end all reference. I just like to be familiar with the expected outcome, and any indications of success or failure are helpful.


Try Lazersteve's General Reaction List!



IR0NHE4D said:


> I will likely just focus on Gold, Silver, Platinum, and Palladium. I'm guessing these are the big 4, but they are definitely easily found in similar equipment.


Since this IS a safety thread, I'll point out that platinum salts, and salts of other platinum group metals (PGMs), can be extremely toxic. There are refiners on this board that are perfectly comfortable with cyanide processing and still won't mess with PGM salts. Personally, I'm recovering PGMs and will send them on to someone else for refining.


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## Anonymous (May 3, 2016)

upcyclist said:


> Since this IS a safety thread, I'll point out that platinum salts, and salts of other platinum group metals (PGMs), can be extremely toxic. *There are refiners on this board that are perfectly comfortable with cyanide processing and still won't mess with PGM salts.* Personally, I'm recovering PGMs and will send them on to someone else for refining.



I'd be one of those- as is Nickvc, and you are quite correct there are plenty of others too. The quandary is that there is an unreasoned fear of cyanide processing, whilst many people seem perfectly happy to take the bigger (albeit longer term) risk with PGM salts. There's a logical argument that could be reasoned that exposure to some of these salts, even in low quantities is far more dangerous than cyanide processing. That's a debate I would welcome with input from those far more experienced than me to make the salient points.


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## Lou (May 3, 2016)

I'm glad to see there's more awareness of so called tetravelent or chloroplatinate allergy. This has been the trend in industry. I have worked diligently to minimize as much as possible those risks in my handling of them by physical and chemical methods. Tetravalent platinum is a necessary evil in its hydro metallurgical process (except, for instance, plating with cyanide) are a necessary evil when refining the metal.

Here are some examples of control techniques/practices:
1. Dedicated handling areas (i.e. a labeled fume hood where any manipulations are conducted so that misting or aerosolization of the material inclusive of digestions, filtrations, hydrolysis etc.). Ideally these areas should have easily cleaned surfaces (PVC, PP, HDPE, FRP). 
2. Carbon filter capture of fume hood draft from
which value may be recovered
3. Borohydride rinse down procedures 
4. Enforced secondary containment and prompt spill response
5. Frequent changing of PPE like gloves, lab coat, and use of full face respirators, no mustaches, use of boot covers
6. Maintenance of Pt solutions as Pt (II)
7. No dry handling of platinum salts -- damp only, preferably in glove box
8. No melting of Pt sponge with excessive halide content (salts)


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## snoman701 (Apr 13, 2017)

I would add, strong acids should not come in contact with organic compounds without serious consideration for what may happen.

This can range from the use of "piranha" type solutions (strong acid & peroxide) all the way to the use of a charmin plug as a filter. 

Review how flash paper is made, or guncotton, to understand the dangers of nitrates with organics.

But everyone should review the following, for how important it is to keep organic liquids such as acetone or alcohol away from strong oxidizing solutions.

http://cenblog.org/the-safety-zone/2015/01/piranha-solution-explosions/

Finally, drug/alcohol was mentioned. I do not drink, but do occasionally use marijuana in a more medical capacity (I have crohn's and fibromyalgia). One thing that is very noticeable is the dulling of the senses, but not in ways that most people will always recognize. 

For me, it's the odor of NOx solutions. My high efficiency furnace kicks out some NOx, and in order to enter the garage, I have to walk by it's exhaust. I will routinely smell it heading out in to the garage, but never smell it walking back, after using. 

Having went to college and had friends that were HUGE potheads, they claimed (and often did) everything, whilst stoned. The most brilliant minds I have known, spend a majority of their time during their studies under the influence. University of Michigan, graduating electrical engineering with honors. It was no big thing for them, but it's clear to me that that simple diminished sense could have serious consequences in a refining capacity, even if you may think you have full control of the situation. Given that the odor thresh-hold and the prolonged exposure damage thresh-hold are pretty close together, this err in judgement could prove to be a very serious consequence.


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## chemtag (Jan 26, 2018)

I had an accident in the lab performing a fusion. I wanted to perform a fusion analysis of a sample from production. The goal was to practice and demonstrate the procedure to a co-worker while seeing how well that sample material fused under these conditions. I weighted out 3 g of sodium carbonate (Na2CO3), 3 g of potassium carbonate (K2CO3), 4 g of lithium metaborate (LiBO2) and 1 g of lithium tetraborate (Li2B4O7). I then mixed this "with 1.8 g of the sample in a small graphite crucible (we do not have a platinum crucible at work).

The graphite crucible was placed in a small muffle furnace already at ~450 C. A small porcelin lid was placed on top of the crucible, where it sat loosely during the heating process. The furnace was manually ramp'd up from 450 C to 900 C over about an hour.

While the oven was being heated, I filled a 1 L beaker with 100 g of 93% H2SO4 and 400 g of DI H2O. A medium sized stir bar was placed in the beaker and the solution stirred for about 20 minutes to allow the heat of the acid dilution to dissipate. I then moved the beaker onto a small stir plate placed on a sagger lid sitting immediately adjacent to the muffle furnace (and also next to the laboratory centrifuge). I placed a large watchglass over the beaker until it was ready for use.

After the furnace had heated to 900 C and held that temperature for ~15 minutes, I prepared to pour the molten sample into the dilute acid solution. After putting on additional PPE for the procedure, I took the watch glass covering the acid beaker off and turned the stir plate on to get the solution stirring vigorously. This formed a strong vortex in the solution.

I then turned off the muffle furnace, opened the door, and using extra long tongs, lifted off the porcelin lid (glowing slightly from heat) and placed it on the sagger lid. I then lifted the crucible out of the oven by grabbing one side with the tongs. I then quickly poured the molten material into the beaker. Within a second of the molten material entering the beaker, the entire beaker exploded with a loud bang. My extra PPE (namely the aluminized jacket and face shield that were on over my regular lab coat and goggles) protected me from the small amount of liquid that I came into contact with. Glass pieces fell onto the ground, and some was launched several feet into the room, but most stayed relatively on/near the lab bench. 

In the moments after the explosion I carefully placed the still red-hot graphite crucible onto a sagger lid on the other side of the room, where there was no risk of it coming into contact with water (which could cause a steam explosion itself).


So, what happened? Fortuitously there is a video of the accident so I can watch it to see if I did something stupid. Unfortunately, to my novice eyes I can't really see anything. Its possible I touched the edge of the glass beaker with the crucible or tongs, but it doesnt look like it. I suspect that I poured the hot material too fast and caused a small steam explosion. The video shows the explosion coming from in the liquid, and I did pour this sample faster than previously (just because I am getting better at it). Perhaps it is also possible I poured the molten material "down" the vortex and it all hit the stir bar/bottom of the beaker, instead of the liquid.

Its now clear that I should have been using a Teflon beaker which would not shatter under the intense heat of a fusion. However, if what I made was a steam explosion, than the teflon beaker wouldn't have prevented this accident (just made it better by not spraying broken glass everywhere). I am not sure if this type of molten-pour fusion is going to be safe enough to continue using. Instead I have read about fusing materials in a crucible at high temperature, letting the whole thing cool to room temp, and then digesting the solid pellet of fused material straight out of the crucible. Does this work just as well? Does it work if I dont have a platinum crucible (I have access to graphite and zirconium right now, and might get a Ni crucible soon too)?


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## Lou (Jan 26, 2018)

Your first mistake was graphite. Glassy carbon is the thing to use if you're going to use carbon, but these are done usually in Pt95Au5 crucibles, which are quite resistant to alkalis. I run mine at 1000 C. Mostly useful for aluminaceous material. I also do a few Na2O2 fusions a week (20-30) in Zr crucibles, though alot of people use nickel for reasons of economy. 

Second mistake was that you poured a melt like that (basically molten alkali oxides and glasses) into a dilute sulfuric acid solution in a glass beaker. You should have used a (poly)methylpentene beaker. Basically the shock wave from acid-base reaction at high temperature, steam formation, etc. is what destroyed the beaker. Thank goodness you had PPE on when conducting this.

If you have a sonicator, you can wait until the reaction is cool and then go from there. The issue is if you conduct fusion in graphite in air, the graphite will oxidize and particles will come off during sonication.


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## chemtag (Jan 26, 2018)

Lou said:


> Your first mistake was graphite. Glassy carbon is the thing to use if you're going to use carbon, but these are done usually in Pt95Au5 crucibles, which are quite resistant to alkalis. I run mine at 1000 C. Mostly useful for aluminaceous material. I also do a few Na2O2 fusions a week (20-30) in Zr crucibles, though alot of people use nickel for reasons of economy.
> 
> Second mistake was that you poured a melt like that (basically molten alkali oxides and glasses) into a dilute sulfuric acid solution in a glass beaker. You should have used a (poly)methylpentene beaker. Basically the shock wave from acid-base reaction at high temperature, steam formation, etc. is what destroyed the beaker. Thank goodness you had PPE on when conducting this.
> 
> If you have a sonicator, you can wait until the reaction is cool and then go from there. The issue is if you conduct fusion in graphite in air, the graphite will oxidize and particles will come off during sonication.



I am aware of the graphite crucible problem (i.e. its not great for this type of fusion), but without a Platinum (or Pt/Au) crucible, I have to work with what I have. And for now, its just a matter of practice and learning these pyrometallurgy techniques. If the little graphite bits contaminate my sample, that is fine. I usually just do a quick centrifuge before loading the digested fused sample into the ICP. Things may change in the future, but I can't force the powers-that-be to buy a 2-3k crucible for a niche analytical technique (for our operations). 

Do you think there is any concern about my pour rate? Or my molten-sample mass versus the mass of water+acid I was pouring into? Could I have poured the stream onto the side of the beaker and caused problems? Or is it your opinion that had I done everything exactly the same BUT been in a Teflon (or polymethylpentene) beaker, everything would have been totally fine?


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## Lou (Jan 26, 2018)

Seeing as a 1 liter teflon beaker is probably a third the price of the crucible (which I can happily turn for you, should you want one), you will want to use something cheap. Even HDPE is fine for this application. My advice would be to pour into a mold, which again are usually PtAu. In your case you can use graphite. Cover it over until it cools with another piece of graphite. Then demold and break it up in a mill or good mortar and pestle. You can add a small amount of LiCl to help it not stick so much.

Generally speaking, molten basic materials and water is a bad mixture and you are hearing this from someone who thought it was a good idea to pour molten KOH slag mixture into water once. Not a good idea. You have to remember that it's not just the thermal mass of the fusion, it's also the heat of the reaction that goes ballistic. I can put a beaker of pyrex in a 5 gallon bucket, put a little dish soap, and make about 300 g of gold shot without break the glass. Sure gold is a better conductor, but the real difference is there's no chemical reaction when it hits the water.

Even making Adam's catalyst (PtO) from KNO3 + (NH4)2PtCl6, it is very scary pouring that mixture into the trough!!


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## cuchugold (Jan 27, 2018)

I might need to get involved with Fluorine, and HF, which I have avoided all my life. I'd love to read detailed safety measures about that.


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## anachronism (Jan 28, 2018)

cuchugold said:


> I might need to get involved with Fluorine, and HF, which I have avoided all my life. I'd love to read detailed safety measures about that.



Sure that's easy. Don't even think about using HF. Park the idea and forget you even thought it.


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## cuchugold (Jan 30, 2018)

Anach: You seem to be the most recent resident master of what cannot be done. 

Here's a tip: HF readily vaporizes a quartz matrix. Yes, it is corrosive and nasty.


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## Yggdrasil (Jan 30, 2018)

Well!
HF is a substance most experienced refiners will not touch if they don't have to.
And the agreed upon pratice, is to walk away if there is no workaround.
Simply because of its toxicity and bad interaction with living or dead tissue.

When that is said, there are people using it still for a number of reasons.
I believe paleontologists and geologists, use it to dissolve the matrix in which objects they want/need is to be liberated from. Just fill in the blanks.

It is not my decision, but maybe we need to give HF a bit of the recent "CN" treatment.
If we assume people are going to use it anyway it may be more productive to give stern warnings and then inform what kind of safety coniderations to take.

Like this: Stay away, stay far away. If you still are going on, do this and this only.

Like I said, not my decision, just my 2 cents.
And I see no reason to use it my self.


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## cuchugold (Jan 30, 2018)

Proposed pilot process is to dissolve quartz, and re-cycle SiF4 vapors back into HF, as safely and cleanly as possible, avoiding free Fluorine, if at all possible. HF is nasty and dangerous. It is what it is. It breaks a 95%+ quartz matrix down to the atom level to free or combine with other metals present. If it can be regenerated easily, there may be an economical gain to be made.


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## Lou (Jan 30, 2018)

cuchugold said:


> Proposed pilot process is to dissolve quartz, and re-cycle SiF4 vapors back into HF, as safely and cleanly as possible, avoiding free Fluorine, if at all possible. HF is nasty and dangerous. It is what it is. It breaks a 95%+ quartz matrix down to the atom level to free or combine with other metals present. If it can be regenerated easily, there may be an economical gain to be made.




Obviously by now you know I work with HF. Lots of it, I guess.

I am not sure it will be cost effective. Also, it will not easily be recycled in the field. Any SIF4 (which is very nasty compound, I only make it to free samples of silicon), hydrolysis of this will make HF but any excess HF in gas stream will give H2SiF6 rather than HF itself.

Unless you found large nuggets of gold in quartz matrix, this is not going to be safe or tenable financially (not at $0.45/lb, which is 49% HF price in bulk).


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## cuchugold (Jan 30, 2018)

As usual, thanks Lou.

So simple hydrolysis will produce either HF or H2SiF6?. Both of these are corrosive to SiO2 and can be recirculated into the "leaching vessel" perhaps?. 

It does not have to be a big vessel or initial quantity of HF, if 95%+ of it can be recirculated. This can perhaps keep the hazard relatively small, with some emergency scrubbing trap?.

The deal is this: Some "garbage tailings" assay X, very small with standard fire assay. If same sample is leached with HF and then fire assayed, it gives nearly 15 grams gold per Ton. Reading Deano's posts and other things I found here and there, I have to reach the conclusion that it is superfine gold entrapped in the particles.


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## anachronism (Jan 30, 2018)

cuchugold said:


> Anach: You seem to be the most recent resident master of what cannot be done.
> 
> Here's a tip: HF readily vaporizes a quartz matrix. Yes, it is corrosive and nasty.



You've got to be kidding mate. 8) 

If you'd joined the forum when I did in 2012 you'd have struggled to discuss anything but Hoke's accepted methods without being frowned upon. I used to get in all kinds of trouble for suggesting different things as did many others. 

The reasons you originally steered clear of using HF are all still there. They haven't changed at all. If you're thinking of using HF on ore, then do you know how the HF is going to interact with all the different compounds that could be present because if you don't then you should. 

One drop of HF on your skin note one drop and you're in trouble. Now I've done a fair bit of acid refining over the years and I can't remember a single day where for one reason or another I've not got a drop of acid either on my clothes, my arms, or elsewhere in some form or another. I'm careful, and I wear PPE but it happens. Certainly more so when you get confident with a process. Now that's a failing in me I accept that however you do not have that room for margin with HF.

For the record I love new ideas, I thrive on finding improvements to processes and ways to improve yields for less time invested. Please don't criticise me for trying to save your ass because that's literally what I was trying to do. No offence taken, I'm just setting the record straight. 8) 

Jon

Edit I re-read the last bit of your comment. It's not how corrosive HF is, that presents the problem. It's what it does inside your body when you get it on your skin even if you wipe it off.

Take a read of this and let me know how you feel about using it. https://web.utk.edu/~ehss/training/has.pdf


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## FrugalRefiner (Jan 30, 2018)

anachronism said:


> If you'd joined the forum when I did in 2012 you'd have struggled to discuss anything but Hoke's accepted methods without being frowned upon. I used to get in all kinds of trouble for suggesting different things as did many others.


Jon, cuchugold actually joined the forum on May 26th, 2010 as HAuCl4. He forgot his password and reregistered as cuchugold.

Dave


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## jimdoc (Jan 30, 2018)

FrugalRefiner said:


> anachronism said:
> 
> 
> > If you'd joined the forum when I did in 2012 you'd have struggled to discuss anything but Hoke's accepted methods without being frowned upon. I used to get in all kinds of trouble for suggesting different things as did many others.
> ...




Maybe when members do that, it should be required to be in their signature what their former identity was.


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## anachronism (Jan 30, 2018)

FrugalRefiner said:


> anachronism said:
> 
> 
> > If you'd joined the forum when I did in 2012 you'd have struggled to discuss anything but Hoke's accepted methods without being frowned upon. I used to get in all kinds of trouble for suggesting different things as did many others.
> ...



Ok cheers that's good to know Dave. In that case he'll remember exactly what I was referring to 8)


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## snoman701 (Jan 30, 2018)

I can tell you that out of all of the chemicals I have worked around, HF is up there as one of the scarier ones. 

The fact that the pain of exposure is delayed just makes it that much scarier. You get most acids on your hands and you know pretty quick they are there. 

What I hate is that after I've worked in gloves for a while, I get sweaty hands...and at that point I don't know if I've got a leaking glove or a broken glove. If it's a strong acid, you'll feel it...if it's HF, that pain could be delayed a while. And if you look at the average amount of "hand sweat" wetness, it is going to be enough HF to land you in the ICU at minimum. 

I accept that at some point I'll have to find a procedure for frosting stones, but I also will not do this until I have a purpose built containment unit....and it will NEVER be a large amount at a time.


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## cuchugold (Jan 31, 2018)

Yes. Thanks guys. It's too dangerous. Forget about it.


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## JoeyJoystick (May 30, 2019)

I am not a gold refiner, but have been working in the oil industry for 35 years of which 15 in South-East Asia. In this sense I am no stranger to chemicals and their dangers. Not an expert either, but I have NEVER had an accident at work nor did the people who work with me or for me. Safety is obviously always an issue and here, much like everywhere else in the industry, slogans are used to make it easier for people to remember safety. Far from specific, but still helpful slogans I remember:

- Better safe than sorry.
- Proper Preparations Prevent P-I-s-s Poor Performance. (Apologies beforehand, but I am hoping this is allowed due to the context…)
- Kiss; Keep It Simple Stupid. Very important! When you keep it simple it is more easy to see the safety traps.
- Good tools are half the job.

And not an expression but still valuable informative one liners:
- Everybody can stop work (or stop others from working) for any safety issue.
- Be very careful and aware of any pressurised gas or possible pressure build-ups.
- Store chemicals properly. 
- Keep incompatible chemicals separated from each other by a fair distance.

When I remember more I will add accordingly. If anyone else wants me to add something just send me a PM.

Joey


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