# fume hood and scrubber



## DropYoTop (May 25, 2012)

I live in a residential neighborhood, and code enforcers are driving around alot (in white impalas with the village sticker on the side) i tired looking everywhere even Google but i find a few things but it not what i need. i was wondering if anyone knows a good plan that i can get a copy of for a good price, Hell ill pay a finders fee if i have to.


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## NobleMetalWorks (May 25, 2012)

You can do a search on the forum and find a ton of information on both. One of the best threads in my opinion to read, is this one.

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

If you read the entire thread, from start to finish, you will learn enough about fume scrubbers that you can either build it yourself or have someone else fabricate it. There are a lot of companies that will fabricate and even assemble what you want, so long as your information is solid. If you read the above thread you will find a few fabricators also. You will also see a few pictures of fume hoods that have been fabricated.

You can also look for fume hoods that asset recovery companies are selling. I ended up with a 4ft brand new (under 6 months old) acid fume hood, with cabinet and all the acid PVC ducting I could ever want from a manufacturing plant closer that an asset company purchased. I did a lot of wheeling and dealing to get it, but in the end I spent a total of $200 for two 6ft hoods that I then traded for the smaller hood to fit my purposes.

You can do a search on eBay for companies that are selling fume hoods, then change the list so that it finds the ones closest to you first. People who sell used fume hoods are a lot of times remarketing or liquidation companies that have other equipment you can use. I ended up getting a rolling mill, a suction pump, an analytical balance, tons of lab glass, and on and on. I am trading labor for equipment, he is giving me the equipment and I am processing his material for free. You hook up with someone like this, develop the business relationship past just purchasing a fume hood and/or scrubber, these people usually know not only about plant closures, but also I-Waste (industry waste). The gentleman that I am doing business with is going to partner with me to purchase large quantities of IC's, that didn't pass QA from Silicon Valley companies.

Also, he has my two fume hoods I traded for the one I currently have. One will sell for 2k and the other 3k USD. If you want me to send you pictures I can, but they are pricey for most people. I found them on craigslist, a property manager was clearing out a rented space, a bio-tech firm went bankrupt and left all their equipment behind, including the fume hoods. One was built in 2009 and the other 2010. She sold them as laboratory cabinets, I ended up buying 40ft of lab cabinets also, at $100 per 4ft.

You can also check Government Liquidation sites like these:

http://www.govdeals.com/

http://www.govliquidation.com/

You can often find a lot of other equipment through these sites, and bid on huge government scrap metal contracts if you are equipped for it.


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## NobleMetalWorks (May 25, 2012)

Here are some other forum posts that you might want to read. Each one deals with fume hoods or scrubbers. It's all excellent information.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=12120&hilit=fume+hood

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=84&t=13454&p=135003&hilit=fume+hood#p135003

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=56&t=12757&p=137680&hilit=fume+hood#p137680

A thread about NOx emmissions

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=47&t=14289&p=143437&hilit=fume+hood#p143437

A thread about one person's set up

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=13739&p=138003&hilit=fume+hood#p138003


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## NobleMetalWorks (May 25, 2012)

You would do well to also read about fume scrubbers, and fume hoods. You don't want a ductless fume hood for example, and you don't want any exposed metal on the inside.

The 4ft Acid Fume Hood I purchased, I modified for my purposes. It had a metal vent (stainless steel) that I removed and replaced with a polyethylene vent. Also it had copper tubing to supply air, vacuum and water, I replaced the vacuum line with plastic tubing to prevent corrosion and have it hooked up to my fume scrubber to pull vacuum. Later I am going to attache it to the vacuum pump I picked up.

You don't want anything metal on the inside, at all. You also might want one with an air flow meter so you can measure the face velocity. An epoxy bottom is common, and desired. You do not want to use hoods intended for Petrochlorate Acid, they are, from what I have seen, stainless steel on the inside.

Before you purchase anything, and if you have not done so already, I would read everything on the subjects that I could get my hands on. Sales people will try to sell you any number of systems that they claim will work. I had one sales person tell me that their ductless fume hood with carbon filter would remove NOx. Can you imagine the danger in that? Spewing NOx fumes into your work area because some joker told you their carbon filter would work.

Scott


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## NobleMetalWorks (May 25, 2012)

One last link, sorry...

I have not spoken with this company, and since I have built one scrubber, and building a second I have no intentions on calling them to see what exactly their fume scrubber is or does. But it might be a lead. If anyone does talk with this company, can you post the response here for other people?

http://escoglobal.com/product.php?id=EFS

Scott


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## DropYoTop (May 27, 2012)

SBrown said:


> One last link, sorry...
> 
> I have not spoken with this company, and since I have built one scrubber, and building a second I have no intentions on calling them to see what exactly their fume scrubber is or does. But it might be a lead. If anyone does talk with this company, can you post the response here for other people?
> 
> ...


 no need to be sorry the more the better, i've haven't replied since i wanted to make an educated reply and i've really been looking at that scrubber design... and was wondering (since i got very little space) if it is a essential for e waste refining. and also was wondering since i work out in my garage (where the setup is going to be) if it safe to be there with the hood and scrubber installed.from what i've read you got quite alot of knowledge and experience in this stuff and ive read you've built one in four hours?and roughly what would be a price on materials on the one you've built if i may ask? sorry for asking you all this but im bring in a few things from lots of different post, and its been confusing.
Thanks
Dean.


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## DropYoTop (May 27, 2012)

DropYoTop said:


> SBrown said:
> 
> 
> > One last link, sorry...
> ...


sorry let me be a bit more clear on the safe part being in the garage with the fume hood. i was wondering if it would be bad if i was in the garage while the setup is in use and collecting fumes.


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## NobleMetalWorks (May 27, 2012)

I put together my first one in about 4 hours of actual labor, it's not hard to do if you have your plans all laid out.

I made my own eductor on the first one, it ended up costing me around $50 dollars. If you purchase them, they are more expensive, naturally. But they work more efficiently. I was playing with the idea of buying a small mill, and some PVC and trying to mill my own, but that's a project best left for another time currently I am just trying to get an assay lab up and going now.

There have been some posts I believe about building a lab in a garage. I am looking for the right building to rent currently, but I am still going to keep my garage lab. I was originally going to install a 6ft fume hood. Here are the two I purchased sitting in my garage, you can see how much room they take up.







I ended up buying three 6 ft fume hoods total, they just sort of fell in my lap. The two in that picture I paid $100 each for. matter of fact, the same place has 54 lab cabinets that they are selling for $100 each. I ended up picking up a lot of the cabinets myself, if anyone would like the contact information, it's in Union City Ca. I can hook you up with the person selling the cabinets

This is the fume hood I traded for:






That fume hood is only 4ft long. If you look in the picture, you will notice that it's next to a door. That is one of two garage doors, not counting the roll up door and door into the house. Normally you wouldn't want to put a fume hood right next to an exit, OSHA would have a field day with that. But since I have a door less than 20ft away I can use, it's within code. When I get a chance, when I'm back home, I'll take a picture of the fume hood, and scrubber together so you can get an idea of how much space they take up. It's right around 8ft in length and about 3 1/2 feet deep for the fume scrubber and fume hood.

I have a stainless steel table next to the fume hood, the scrubber sits under it. I bolted down a piece of polyethylene on top of the stainless steel and treated it so it wouldn't be slippery, that is where I have my reaction vessels set up. Because my reactions are contained within an enclosed system, I don't do my AR reactions under the hood. I use my hood for everything else though. It had an acid stainless steel vent with an 8 inch outlet that I changed to poly, I ordered the poly vent from US Plastics. I had to slim down the vent for my exhaust set up. The reason I put the fume scrubber next too the door was that the roll up garage door would have prevented my shroud from being all the way up. If I could, I wouldn't have it next to a door the way it is now.

So far as the cost involved in making my own fume scrubber, my first one was super cheap. I bought a poly chemical tank with a lid that screws on for my access, and enough room for the spray stack to be attached to. I paid $50 for the tank. The pump I bought new from US Plastics, it was right around $250, all said and done. The spray nozzle I already had, it was something I had purchased for a salt water tank that I adapted to use for this, but it's cost when I bought it was probably about $10 dollars. Since I made the eductor, I kept the price waaaay down. I think it ended up being 50 worth of materials, and I purchased them all from US Plastics, if you would like I can give you a list of the parts I used to make my eductor. The spray down stack was pipe I took out of the same place the fume hood came out of. The Re-Marketer I hooked up with allows me to go with him when he is bidding on a room, so I can remove equipment, pipe, or other things I can use. Otherwise 12' PVC pipe can be a bit expensive. I bought the bio balls I used for the spray down stack off eBay, I used new ones because any I have extra laying around have all kinds of growth on them from being in salt tank filters. Total cost of the bio balls might be $30. I also did another thing that wasn't in the original design, I put floating plastic balls in the tank. I read about the same type thing on US Plastics, but the balls were expensive so I found my own, the idea is that the balls cover the surface area of the water and by doing so force the water to retain the gasses longer than normally they might. It's used in industry, for the same reasons in open vat tanks. The total amount of materials I use to neutralize the minor nitric acid that can collect in this enclosed system was about $50.

It adds up fast, but you should be able to build your own fume scrubber, that works better than what you can buy on the market for 5 times as much. I was talking with an engineer for a company that also sells fume scrubbers, so I asked him about the type I was building, at the time. He only had to think a minute, then he told me that it was a smart way of doing it, and that it was probably, literally, the best design for my type of operation. He said brilliant more than a few times. 4Metals really outdid himself posting this design. Even with my home made eductor I am pulling 10cfm, actually a little more.

Oh yeah, I bought a plastic welder from Harbor Freight to put all the pieces together, and if you are interested, Harbor Freight has instructional video's on how to properly use a plastic welder, using the very model you purchase.

If you are smart, and you are willing to do a little hustling, you can do this for really cheap. I found a secondary supply of 12'' PVC for spray down stacks. I was driving by a city yard, I pulled over and walked into the yard. A bunch of guys were having lunch so I asked them if they had any scrap PVC underground water pipes, they had 12'' pipe, and just gave it to me. It's what I am using on my second scrubber I am putting together.

I am not replacing the first fume scrubber, I am making a totally new one for the assay lab I am putting together.

Have any questions, just ask, I probably said a lot more than you wanted to know. Post any questions here and I'll try to answer them if I can. You should know though that there are many people who have far more experience in all this than I do, that might know better. I answered because this is something fresh in my mind that I have been putting together for awhile now. It's easy to write about something you are currently doing.

And like always, if I said something that is wrong or incorrect, or misleading, please correct me.

Scott


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## NobleMetalWorks (May 27, 2012)

DropYoTop said:


> sorry let me be a bit more clear on the safe part being in the garage with the fume hood. i was wondering if it would be bad if i was in the garage while the setup is in use and collecting fumes.



If you build the eductor scrubber, it's an enclosed system. Meaning there is nowhere for the gas created by your AR reaction to go anywhere but into the fume scrubber. This makes it very safe, far more than if you were doing this under a hood. I use the fume hood for all other reactions, and small assay samples. I ran the vent from the scrubber, straight up through the drywall roof, then the house roof and made sure it was a good 18 inches from the surface of the roof. The exhaust goes through the fume scrubber. Haven't seen any discoloration around the vent I cut in the roof yet. I also test for any gasses escaping from the vent by using red dyed shop towels you can buy just about anywhere. You put the towel over the outlet of the vent If any acid fumes come into contact with the towel, it will turn purple/bluish like this.






Scott


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## NobleMetalWorks (May 27, 2012)

I also wanted to add this...

If you are working in your garage, it's smart to open doors wide enough to affect air flow. I have a huge shop fan I place at the door near my fume hood, to push air out of my garage, by adjusting the height of my roll up door I can create air movement, much like you do with a fume hood. I just adjust the door as if it were a baffle.

I also do not have any cars in the garage while I am working. This is for two reasons. First, if I do have any fumes escaping, I don't want them interacting with the metal of my cars. When I was doing this outside on a table, metal tools that were nowhere near the rusty fumes I could see, were starting to show corrosion. Imagine what it would do to your car. The other reason for pulling my car out of the driveway, is so that I can block the view of nosey neighbors. The reason I have the fan on the door near the hood is that I don't want to be pushing any air out towards my car on the driveway.

It depends on how well your system works if you should be doing this while in the garage, and only you can answer that.. I do, but I feel reasonably comfortable that I have built equipment that works, and the equipment I purchased functions as expected.

Side note, if you are going to use any metal close to where you are working, you can buy a can of plastic coating that you can dip your tools into. If you need information on that let me know and I'll post a picture of what it looks like.

Also, if you have any sockets or light switches close to where you are working, you might want to protect them from fumes as well. I ended up removing everything from that wall and nailing sheet rock, and over that long pieces of polyethylene I picked up from the same re-marketer, he gave them to me. I have long strip outlets, which I got from the same source, on an isolated circuit and connected to an UPS. This way I can power balance heavy loads. I had an issue when I used my hot plates with other equipment that drew a heavy load, popping a circuit breaker. I have no problems now.

Scott


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## DropYoTop (May 27, 2012)

SBrown said:


> I put together my first one in about 4 hours of actual labor, it's not hard to do if you have your plans all laid out.
> 
> I made my own eductor on the first one, it ended up costing me around $20 dollars. If you purchase them, they are more expensive, naturally. But they work more efficiently. I was playing with the idea of buying a small mill, and some PVC and trying to mill my own, but that's a project best left for another time currently I am just trying to get an assay lab up and going now.
> 
> ...


oh thats an amazing deal you've gotten on the fume hood. and please do go into detail about the eductor. Ive been looking at pump at us plastics and what exactly would i need? i think i can get my hands on a 50 gal tank, and the sprayer is it like an "internal" pvc tupe inside the pvc tube or what is it exactly? and two more question. http://goldrefiningforum.com/phpBB3/download/file.php?id=7462 what kind of pipe is the (piping flow pattern) and that bottom peace outlined in black (pump to drive eductor and feed scrubber water)
Thanks 
Dean.


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## NobleMetalWorks (May 27, 2012)

Here is a good video on how to make an eductor, I think this particular guy was making one for an aquarium. I have used the same method with different parts for the last 20 years, making cheap eductors for my aquariums. If you have the correct sizes you can make one that works, maybe not as good as one you can purchase off the shelf, but they do work.

http://www.youtube.com/watch?feature=player_embedded&v=j47XbRzCcNo

I do a few other things I'll try to explain below, but this is the general idea. If you follow this video with a few minor changes you will be able to pull it off without a hitch.

First, you need one of these. Notice it's threaded, I used a threaded one because pressure does build at the eductor.

http://www.usplastic.com/catalog/item.aspx?itemid=45312&catid=738

One of these

http://www.usplastic.com/catalog/item.aspx?itemid=45540&catid=738

You are going to drill a hole large enough to accept the 1 1/2 inlet pipe, just like the pen casing in the video above.

Two of these, to go on the T and the bottom of the eductor you are building, so that it can accept pipe that is not threaded.

http://www.usplastic.com/catalog/item.aspx?itemid=45970&catid=738

And now for the few minor changes. I ended up plastic welding everything in mine, also the reason why I am not going to offer to take it apart and re-build it like the video. I did not use any glue, I just screwed the fittings together, then plastic welded all around the joints.

I built my own throat using soild PVC stock I already had, similar to this

http://www.usplastic.com/catalog/item.aspx?itemid=23750

Small enough to fit inside the PVC T. For the bottom of the eductor, I used three inches to make the throat. I used a step bit to taper the entrance and exit. I cut a very small piece for the receiving end of the eductor, I again used a step bit to mill the inside to a nice V, then fused it to the inside. This step isn't required, and the solid stock is expensive, the only reason I did this was because I had the PVC stock already.

Alternatively, you can give these guys a call.

http://www.millerplastics.com/eductors.html

Their largest one will produce a 10cfm pull at the T. I just purchased their 2'' eductor. If you want to make sure, you can call and speak with the engineer who designed their eductors. Ask for Melvin.

Scott


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## Palladium (May 27, 2012)

I to looked at renting some place to refine Scott. Then i decided to build my own room which came out cheaper and better for me considering i built it right behind my house.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=9722&hilit=forum+contest&start=120#p126854


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## NobleMetalWorks (May 27, 2012)

Palladium said:


> I to looked at renting some place to refine Scott. Then i decided to build my own room which came out cheaper and better for me considering i built it right behind my house.
> 
> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=9722&hilit=forum+contest&start=120#p126854



I had 20 acres in Northern California, off the beaten track at the end of a fire road in the middle of nowhere, bordered by a stream and river with a pond, I was planning on making it my bug-out residence just in case the world went down the toilet and I need to live somewhere I could sustain a life, off the grid. I had to sell it.

I will eventually find another piece of property, similar...

I am still building out my garage, finishing it really. But with my new contact for buying Silicon Valley i-waste, there is no way I am going to be able to process the volume of material I now have access to, in my garage. I wish I could build out a nice lab in the backyard, but the size of my lot along with city codes on building out buildings prevent me from doing so. I have to move my operation into a bigger place. I need large equipment to process large volumes and I just don't have the room in my garage for it. You are lucky, ideally that's what I eventually want to do.

I bought a couple 20ft containers at a State Auction that had been used for a marijuana grow operation, they have been painted with some type of white polymer plastic material on the inside, and already wired and vented. I just need to replace the metal parts with PVC in the venting system. I am planning on building them out for an acid room, and assay room so that when I move to a property, or another place, I can have them picked up and moved without any issue. I actually got the idea from someone on this forum, it's not my idea but it's brilliant.

Anyway, I'm jealous... :mrgreen: 

Scott


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## Palladium (May 27, 2012)

Yeah, you need a lot more room.


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## NobleMetalWorks (May 27, 2012)

I just hope that once I have the room, I will being able to process material on a regular basis.

I'm sure you already know how fortunate you are, but I'm going to say it again, you lucky... :mrgreen:


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## Palladium (May 28, 2012)

Actually it works out pretty well for me. Smaller is better in my case. I do a lot of karat jewelry so the volume of my source material is low. When i do electronics they come to me already stripped and concentrated, like fingers, processors, or pins. You would be surprised how much gold can be run through such a little room. Wish i had one of those container though! :mrgreen:


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## NobleMetalWorks (May 28, 2012)

That's what I have been doing, concentrated material. You can make a good living cherry picking. And reading your posts, I am sure you are making a very good living.

I made a few contacts on Karat jewelry, and I may still take on a few people I have made contact with. But the sheer volume of I-Waste (industrial waste) that I now have access too seems too good to pass up. So I am gearing up and will be able to do both. I just hope I am moving in the right direction. I think I am, but like with most things only time will tell.

Scott


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## Palladium (May 28, 2012)

I do alright. I've hung around here so long that you can't help but to learn how it's done. I don't run full time believe it or not this is a hobby and i have a real job every now and then. But i do like to fire the old lab up from time to time. I can say that it has payed for it's self in many ways and just not monetary. It's fun and i use the proceeds to benefit others in ways i couldn't had i not found this hobby or this forum. I've talked to people the world over from so many fields and walks of life. I've seen the great and i've seen the scum. All in all it's been a hell of a ride and i get to meet some great and exciting people along the way. Life is an adventure that very few get to really experience because they tie themselves down with different things. Chains so to speak. I don't want my hobby to become my new chain. I learned that lesson from Harold. Money is not my motivating factor. It may come with the territory so to speak, and it nice to have, but it's not what make life go around. I enjoy it just the way it is.


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## cbarney522 (May 9, 2013)

I spent an afternoon building a primitive fume hood for my silver refining hobby. You can view the YouTube video at: http://youtu.be/JeoBvjyMw74.

I used a $5.00 leaf blower motor I picked up at Goodwill. I cut off the intake cover and screwed a small paint bucket onto it. On the exhaust end I glued a 90-deg PVC elbow which will connect to an upright PVC pipe to be mounted on my back porch. All fumes will be sucked up and blown into the air 10 feet up at 150 mph. Total cost to build was around $30.00. Time: 4 hours. Negative comments from wife: none.

This isn't a solution for indoor chemistry! It's just a solution to enhance my safety when I'm working outside. I don't want to accidentally breathe any nasty fumes.

I'd appreciate comments and critiques.


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## squarecoinman (May 9, 2013)

cbarney522 said:


> I spent an afternoon building a primitive fume hood for my silver refining hobby. You can view the YouTube video at: http://youtu.be/JeoBvjyMw74.
> 
> I used a $5.00 leaf blower motor I picked up at Goodwill. I cut off the intake cover and screwed a small paint bucket onto it. On the exhaust end I glued a 90-deg PVC elbow which will connect to an upright PVC pipe to be mounted on my back porch. All fumes will be sucked up and blown into the air 10 feet up at 150 mph. Total cost to build was around $30.00. Time: 4 hours. Negative comments from wife: none.
> 
> ...



I like your creativity , I would extend the outlet pipe, to keep it further away from you just in case.
I think that nitric will eat your motor, but it is a 5 dollar motor and depending on how much you will process it may last for a long time. 
Some people may laugh at your Idea, but it is a lot better then just working in the open air

scm


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