GF watchbands

[Harold_V]

How much household ammonia do I use to wash?

Thus far, after AR, I decant with water several times. Then I HCL
Rinse some more.
I would assume I drop in as much ammonia in one of these washes as I did with HCL (in my case, for the 2.6g button, I used maybe 2-3 ml).

The amount isn't critical. I used to cover the preciptated gold, then heat.

After the ammonia wash, I would expect to rinse repeatedly (under heating pad heat), stirring. By then, of course, the gold is starting to clump.
~~ Do I then crush the clumps to make sure it's rinsed or just stir?~~

I avoided contact with the gold, but I also kept the vessel covered with a watch glass, and boiled each operation. If you mess with the gold much, you start scratching the beaker, which renders it virtually useless for future precipitation. The brisk boiling will flush the cemented gold of dissolved solids adequately, especially if you have double refined. If you have, there's precious little to be removed, anyway. It should have all be left behind in the barren solution.

By the way, my ammonium hydroxide wash came in the middle of the two HCl wash/rinse cycles. Seemed to work for me, and I could often see the results of the ammonium wash.

Lastly, should my last two rinses be with distilled water?

Certainly does no harm---but I used only tap water for gold refining. I never found it to be a problem, and I achieved a level of quality that was more than acceptable. I do NOT claim to have achieved 4n's, however, but I exceeded 9995 routinely. You can tell if your gold is pure--it forms no oxide skin when melted, and cools bright. Appearance is NOT improved by pickling.

Cold, here, isn't an issue, but we sure as hell get our share of rain (cool and damp). That's the way it is in the pacific north wet. :lol:

Harold

 

[Nickpearl]

Not sure what happened here. I precipitated using SMB and although I'm getting some lighter brown on the bottom of the beaker, I have this floating red concentration around the top. Any ideas what this may be? I'm sure I cleaned, cleaned, cleaned.
Thanks,
Nick

 

[butcher]

I would try stirring it.

 

[Palladium]

Some colloidal gold suspensions can be red???

 

[Harold_V]

Stannous chloride is your friend. Test the solution. If you get no reaction with testing solution known to be good, discard the brown solution. I don't claim to know what it is, but if it doesn't test positive, does it matter?

That it has stratified, in my opinion, rules out any values. I do not recall ever seeing a solution of precious metals stratifying.

Harold

 

[Nickpearl]

Thanks, all.
I'll stir and check what did drop at the bottom.

Now another issue. I have made two batches of Stannous per Lazersteve's formula. I snipped 2 grams of tin I got at the hardware store and used 40 mg of HCL. I got the fizzing, the remaining tin on the bottom and the yellow liquid.
When I used a q-tip to put a couple drops of solution I knew to contain gold on a napkin, then another q-tip to touch with Stannous, I got nothing.
Would I need to buy tin powder to make this work?

 

[niteliteone]

Are you sure the hardware tin was "pure tin" :?:
Whenever I make stannous it is always a clear liquid. I use 30 ml HCL and 2 grams of 95/5 tin solder.
I would be very suspicious of the yellow collor of your solution.
Tom C.

 

[Harold_V]

Testing solution made from crystals may have a hint of yellow, so that, alone, isn't a sign of a bad solution. If the solution is opaque and pale yellow, it may not work properly.

A standard gold solution should be at hand, always. That's the way one tests stannous chloride. If you have no means to test your stannous, it's not a great deal better than having no stannous chloride.

Harold

 

[Palladium]

Excess oxidizer ( Nitric, H2O2, cl ) in your gold solution will cause the test not to work.

 

[Harold_V]

Is that 1/20th of the weight of the caps or the whole watch band?

Generally, caps only, and don't forget that's where the wear occurs, so they won't yield as they're represented.

Some bands, such as those for women's watches, are gold filled everywhere aside for the internal mechanism (springs).

Harold

 

[goldenchild]

I found a silver watchband and I thought of this post. As you can see it has a copper tone to give a rose gold appearance. You can also see the silver tarnishing through where there is wear. Just looking at it I believe this is NOT a 100% silver band. I'll post pics if it turns out to be an all silver band.

 

[Claudie]

What does the inscription read?

 

[goldenchild]

"KREISLER
GOLD CONT 025 TOP
???? BOTTOM"

Unfortunately the one word is worn on both sides :x

 

[Claudie]

Gold Content.025, is Kreisler's 1/20 12K gold-filled mark. I'm not sure about Silver.

 

[lazersteve]

Is that 1/20th of the weight of the caps or the whole watch band?

As Harold already stated the caps are what is actually gold filled. I'd like to add that the majority of the single sided bands (only tops GF are capped) I checked from a very large cross section of an 80 pound batch contained 25-27% gold filled caps by weight for both mens and womens varieties. Stated another way :

Total weight of bands 1000 grams:
Total weight of GF caps after removal: 250-270 grams
Estimated maximum gold yield for 250 grams of 1/20 12kt tops for brand new bands and 100% refining returns: 250g x 1/20 x 12/24 = 250 x 0.05 x 0.5 = 6.25g

Be aware that some bands that appear gold plated or filled are actually enamel or lacquer coated. These are commonly marked CHINA and not 1/20 12k GF. Look for the GF hallmark on either end of the band on the bottom side or end of the band near the watch. This lacquer layer can be scratched off and will flake in some cases when it is heavily worn or tested with acid.

Steve

 

[nickvc]

Steve I think in your calculation you meant to say maximum not minimum amount of gold likely to be recovered.
In my experience gold filled goods rarely come anywhere near what the marked content should be and I think that is mainly due to the fact that even the new never worn items have more work done on the facing gold surface than on the hidden base metals, once the stamping or forming operation is completed and the item is constructed the item will go for finishing / polishing and that will only be on the gold surface. I dismantled a few new never worn watch bands and assayed the gold filled tops and they were below what the stamp said by some margin and if worn and of some age the assay will be even less.
A personal view but if buying old worn gold filled I'd not want to pay more than 50% of the marked content and new still packaged items 70%.

 

[lazersteve]

You are correct, thanks for catching that.

Corrected.

Steve

 

[goldenchild]

So I took the watchband apart and it turns out it is on of the rare "100%" silver bands. The part that the caps lay on was very soft and shiney so I decided to test it. I knew right away from the scratch that it was silver because of how soft it was and the bright white scratch. So the take away from this... double and triple check all your scrap.

Bonus Pic!!!