Anyone came up with a technique or process for watch bands ? _reverseAR_

[2002valkyrie]

It seems that every time I process watch bands I end up irritating my wrist to the point of extreme fluid buildup. Has anyone came up with a process that has less labor involved?

 

[glondor]

Best I can offer is I use a pair if 90 degree bent needle-nose pliers, and I sharpen the tips just a bit. For a change up of motion, I use a pair of straight side cutters with the tips sharpened a bit as well, and switch off as the repetition becomes annoying.

http://www.amazon.com/TEKTON-3520-6-Inch-90-Degree-Pliers/dp/B000NPT5VM/ref=lp_553314_1_22?s=power-hand-tools&ie=UTF8&qid=1399582146&sr=1-22

http://www.amazon.com/Irwin-2078308-8-Inch-Diagonal-Cutting/dp/B000A0OW1S/ref=lp_553314_1_21?s=power-hand-tools&ie=UTF8&qid=1399582146&sr=1-21

 

[Anonymous]

Glondor I really wish that I could thank you or give a thumbs up that post. That was really helpful mate.

Thanks

Jon

 

[glondor]

You are welcome! Here is another little trick I use. It really takes a huge amount of strain off of the fingers. Some times I put a small splint in as well on the fingers that get used as the fulcrum. Just a couple of wraps of heavy paper towel and a few wraps of electrical tape. Much better than gloves. It allows me to do quite a lot in 8 or 10 hours over several days. These 2 tubs are part of the caps from 30 pounds of bands.

 

[2002valkyrie]

Man I appreciate your tips but I guess what I need is some free labor, ha ha. I have around 150 lbs. of gold filled that has to be processed and my hands are getting tired. I think that I am going to have to build a mini shredder. I have worn out 2 pair of tin snips and 2 pair of side cutters and it seems that I am getting more and more behind every day.

 

[richoc]

Hi,
First post here but been around some time.
I do my gold filled watch bands in a small stainless strainer basket in my sulfuric cell.
I used to break them up for hours, but not is simply not needed.
The small strainers curve fits the watch bands real nice.

Current is what makes it work and the basket just needs to touch each gold coated surface.
Mens watch bands are simple.
Ladys need to be moved around a bit to get it all off.
If your bands are the nice boxed kind with the in sides are gold ...you just pull on each end till all the springs break.
then put it in as a coil.

 

[nickvc]

Try dissolving the stainless in hot hydrochloric, after incineration, it's slow but beats manually stripping the damn things. Even if it just releases all the tops you can at least just hand separate them a lot easier.

 

[goldenchild]

Man I appreciate your tips but I guess what I need is some free labor, ha ha. I have around 150 lbs. of gold filled that has to be processed and my hands are getting tired. I think that I am going to have to build a mini shredder. I have worn out 2 pair of tin snips and 2 pair of side cutters and it seems that I am getting more and more behind every day.

I have a solution. Sell me some of it. Seriously. What do you want for them? GF bands are my favorite to process.

 

[4metals]

Watchbands that are mostly stainless steel would likely benefit from a technique that allows the gold to dissolve in the acid but not the stainless.

Taking advantage of the fact that stainless steel can be made more resistant to corrosion by a process of nitric acid passivation, the acid mixture can be made up to take advantage of the oxide film the nitric acid can form to protect the stainless and still dissolve the gold.

How is this possible?

A quick summary is to make up a mixture of nitric and hydrochloric acid with percentages quite different than normal aqua regia. This mixture will have the effect of passivating the nitric and at the same time dissolving the gold.

This is how it is done.

First off it is good to have a rough idea of how much metal you actually want to dissolve. Since you have been tearing up your hands dissecting these watches, you have an idea of what percentage of the bands are worth digesting and what percentage is the stainless. Using this valuable knowledge we can determine how much acid to use to digest what we want to digest and not attack the stainless.

Based on the fact that a liter of aqua regia will dissolve (more or less) 7.5 troy ounces of metal, Calculate how much aqua regia you need to dissolve just what you want to digest.

Now take 80% of that volume you just calculated and that is how much Hydrochloric acid you will need to add.

So lets say you have calculated that the batch you want to process will have a pound of metal you need to digest. A pound is 14.583 troy ounces. So 14.583/7.5= 1.944 (call it 1.95) 80% of that is 1.55 liters of hydrochloric.

We want to make up a solution that is 97% nitric acid water mixture (50/50) and 3% Hydrochloric. So that means we need 51.66 liters of the nitric water mix plus the hydrochloric. That is a lot of nitric but 1 pound of watch ends is from a good number of bands. (.03*X=1.55) total acid required (51.66*.97=50.11) liters of nitric water mix.

So add all of the nitric to a bucket first then stir in the hydrochloric acid. Now add the watchbands and the reaction will kick off and die when the metal dissolved consumes all of the hydrochloric. The stainless will have passivated and will not dissolve.

So a small guy may say that's a lot of nitric, and it is, but it performs the necessary reactions.

Before we move on to removing the gold from the acid we should discuss how this can work for a small guy.

Calculate the amount of acid for 1 ounce of watch ends (1/7.5=.13333 liters X .8 =0.106 liters HCl
.03*X=.106 =3.55 liters total acid 3.55*.97=3.44 liters of nitric water mix.

Mix the acid and add enough bands to get close to the 1 ounce of ends you want to dissolve. When the reaction dies, filter the acid off and add more watchbands and slowly add more hydrochloric. The goal here is to use the nitric until it starts to attack the stainless, then the acid needs to be replaced with a new 97% / 3% solution and start over. In time you will determine how many watchbands you can process with a single batch of acid.

The gold is in the filtered solution with a lot of nitric. The nitric needs to be neutralized before the gold will drop out. Sulfamic acid is the way to do this. It is imperative that you keep track of exactly how much 70% nitric you used to start. For every milliliter of nitric you started with add (need I say cautiously) 1.5 grams of sulfamic acid.

Then drop the gold with your precipitant of choice.

So now you have to decide is the use of more nitric worth saving your hands! All refining techniques involve trade-offs, this one requires nitric which does not come easy to some smaller refiners.

 

[Anonymous]

Is it also a good idea to keep this particular reaction cooled?

 

[4metals]

I have never had to cool the digestion reaction but I never added heat either. The relatively low percentage of reactive metal and the limiting quantity of HCl keeps things in check. Once the reaction stops digesting the non stainless alloy, the HCl is used up and another increment of up to 3% HCl can be added. The goal is to keep the available free HCl at a low percentage and the nitric will work with it to digest the soluble metal while it maintains the passivity of the stainless.

You will get to a point where the acid begins to attack the stainless and then it is time for a fresh blend.

I set up a client to do this on a scrap type he is seeing regularly of stainless bracelets with small 14K gold inlays and diamonds set in the gold. He puts up into this acid blend 75 pounds of scrap and recovers about 15 ounces of fine gold and all of the diamonds just drop out. That is under 1.5% of the total weight as fine gold and it is a big savings not to have to dissolve all of the stainless steel to recover the gold and diamonds.

 

[Palladium]

I believe this is only the 2nd time i have head this topic discussed in this detail. The first time was a discussion between you, Chris, and Harold i believe. Whenever it was discussed before the logic of it slapped me in the face! With a little experimenting i began to use this technique on stainless and since then it is one of my favorite tools in my tool box. This would be a tip that people would do good to take notice of.

 

[4metals]

I have not used this process on stainless and gold filled before, although the same principles apply. Have you done this with watchbands Ralph?

If so please comment.

 

[Shark]

4metals

That is the difference in knowing chemistry and reading about it. It is one of those posts that makes the lights pop on when read. :idea:

As I work through my small experiments, my on hand materials are three watch bands that I haven't got to yet from a lack of knowledge. Down the road I will be back to study your post more before trying it and possibly have a few more watch bands to add to the test run.

Thank you for that lesson.

EDIT: to repetitive

 

[Anonymous]

I have never had to cool the digestion reaction but I never added heat either. The relatively low percentage of reactive metal and the limiting quantity of HCl keeps things in check. Once the reaction stops digesting the non stainless alloy, the HCl is used up and another increment of up to 3% HCl can be added. The goal is to keep the available free HCl at a low percentage and the nitric will work with it to digest the soluble metal while it maintains the passivity of the stainless.

Thanks 4metals so in essence, if you were using stainless steel products with a much larger percentage of gold present then would the possibility of heat being generated increase with the gold content? Assuming of course that I'm reading what you are saying correctly and not interpreting it the wrong way 8)

 

[nickvc]

Jon if you start with the nitric and slowly add the hydrochloric it slows the reaction and hence keeps it cool enough to avoid boil overs, the trick is not to rush / push the reaction.

 

[4metals]

Thanks 4metals so in essence, if you were using stainless steel products with a much larger percentage of gold present then would the possibility of heat being generated increase with the gold content? Assuming of course that I'm reading what you are saying correctly and not interpreting it the wrong way

This process is great for lots with a large quantity of stainless containing a relatively small percentage of metal for selective dissolution. The ratio of Nitric to Hydrochloric is so skewed from normal aqua regia that mixing it up for lots with a high percentage of dissolvable metals would require more acid than a normal aqua regia digestion and it is doing so with the acid you need to get rid of to precipitate the values.

This excels for stainless steel scrap with under 10% aqua regia soluble metals in it. It is truly a niche solution to a refining problem.

 

[FrugalRefiner]

It is truly a niche solution to a refining problem.

I'll bet you've got a few more of those up your sleeve. 8)

Thank you for sharing this one with the forum. Although I don't forsee ever doing large quantities of watch bands, it's great to know a technique like this. It helps to expand our thinking. :idea:

Dave

 

[Lou]

Ah, but then the issue is how do you get the gold out from all that nitric acid?

Sure, it can be extracted with solvent, with resin, or certain reducing agents but they all have their pitfalls.

 

[Palladium]

I have not used this process on stainless and gold filled before, although the same principles apply. Have you done this with watchbands Ralph?

If so please comment.

I don't use it so much on watch bands as i do gold filled stainless eye glasses. I hate watch bands period!, But it will work on them to it's just harder to clean up. On the flip side of that you can do the opposite to digest any stainless that might get mixed in with your gold filled. The formula for doing this is just pure experience would be the only way i know to describe it. I'm not really one of those lets measure it to the ml type of guys. I just start pouring and watching and i know when to stop or at least slow down! :mrgreen: Once you get better at it over shooting the nitric can be controlled pretty much within reason. I wonder if this would be a good place for a formate reduction? It works for silver, but i don't know if it would work for gold would it? You to gentlemen are the brains.


Here are some eye glasses i striped using that technique.