# The Pawnbrokers Guide to Testing Metals



## Pawnbroker Bob (Oct 30, 2008)

Here you go guys. Everything you need to know about testing metals from this months edition of Todays Pawnbroker.

Enjoy!

Pawnbroker Bob


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## qst42know (Oct 30, 2008)

Great post. Thanks Bob


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## Pawnbroker Bob (Oct 30, 2008)

Your welcome qst42know.

I've been using these same methods for 25 years.

A couple of other tips..... 

A nice smooth dark river rock makes a great touchstone. Or any dark slab of microcrystaline quartz cut from a geode etc.. 

I keep a tupperware tub with a soultion of water and baking soda that I drop all the tested articles in to neutralize the acid then rinse in clean water. 

Considering the onset of HIV, ADS Hepatititus etc... I also have a small tub with 50/50 water and bleach. All the earrings studs etc get a soak in that for a bit before I start really testing them. Play it safe. 


PB


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## qst42know (Oct 30, 2008)

Do you think a stripped 486 cpu ceramic would work for a touch stone? 

Kinda full circle recycling :lol:


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## macfixer01 (Oct 31, 2008)

Thank you for the post!

macfixer01


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## butcher (Oct 31, 2008)

save that bleach solution sanitizer, to recover the gold its disolving


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## Pawnbroker Bob (Oct 31, 2008)

Qst...

Sure, I am going to try that myself. Good thinkin!

An old ceramic dish works in a pinch too. Just rough it up. 

Yup I do recover that bleach water. =)

PB


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## Lou (Oct 31, 2008)

Very smart about the disinfection procedures Bob. You continually impress me with your thoughtfulness.


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## Juan Manuel Arcos Frank (Nov 2, 2008)

Thank you,Bob...vey nice book


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## goldsilverpro (Dec 17, 2008)

Excellent article, Bob. Probably the most complete writing that I've seen on the subject.

The "red acid", for testing silver, that he speaks of, is a combination of nitric acid and potassium dichromate.

He says that there can be cadmium and/or cyanide on silver contact points and that these make it very hazardous to melt. Most do contain cadmium. None, however, contain cyanide, unless the seller was trying to refine them himself, which is unlikely. In any case, don't melt silver contact points.

His discussion of silver flake, plated out of photo fixer, is very poor and incomplete.

Concerning gold plate. There is a thin layer of nickel plate underneath most all gold plate. The gold is so thin that it only takes a few strokes with a pencil eraser to rub a spot of it off. This exposes the white nickel below, which is easily seen in contrast to the yellow gold around it. I have used this test 1000s of times. I got so good at it that I could get a pretty good estimate of the thickness of the gold plating. Of course, this won't work for gold filled.

I remember an excellent article in the "Gold Bulletin", many years ago, that used a white touchstone. I think that it got heavily into PGMs also. I've tried to locate it, but have had no success.


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## mlgdave (Apr 13, 2011)

Does anyone know the ratios of acid in the test solutions? Instead of paying 29.00 on ebay I would like to make my own? I imagine its just different formulations of nitric and Hcl?

mlgdave


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## Fournines (Apr 13, 2011)

Cheaper...

http://www.ajstoolsonline.com/mystore/test-stones-1.html


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## samuel-a (Apr 14, 2011)

mlgdave said:


> Does anyone know the ratios of acid in the test solutions? Instead of paying 29.00 on ebay I would like to make my own? I imagine its just different formulations of nitric and Hcl?
> 
> mlgdave



I can't find the post, it's by Harold or GSP (sorry can't remember who)

so I'll just write the ratios:
10K - 22.2ml nitric to 7.4ml distilled water
14K - 23.7ml nitric to 5.9ml distilled water to 10 drops of HCL
18K - 5.9ml nitric to 5.9ml distilled water to 22.2ml HCL

for 22K i just used 1 part nitric to 4 parts HCL

That is working great for me.


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## mlgdave (Apr 14, 2011)

Awesome! Thanks!

mlgdave


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## jimdoc (Jun 30, 2011)

Thanks for bumping this thread, The Pawnbrokers Guide to Testing Metals needs to be seen by all newbies.

No thanks on your spam.

Jim


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## samuel-a (Jul 1, 2011)

jimdoc said:


> Thanks for bumping this thread, The Pawnbrokers Guide to Testing Metals needs to be seen by all newbies.
> 
> No thanks on your spam.
> 
> Jim



Who? What? Why? and When?


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## jimdoc (Jul 1, 2011)

samuel-a said:


> jimdoc said:
> 
> 
> > Thanks for bumping this thread, The Pawnbrokers Guide to Testing Metals needs to be seen by all newbies.
> ...




They seem to have been booted for the spam.
Spam usually disappears faster here than in Rosie O'Donnel's refrigerator, and that is a good thing because spam sucks.

Jim


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## Acid_Bath76 (Jul 1, 2011)

Pawn Bob, 

Thanks for the PDF!! It's just what I was looking for!! 

--AB


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## Dirtdiggaler (Sep 4, 2011)

Great read! Thank you for posting that.


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## Lobby (Jan 17, 2012)

samuel-a said:


> mlgdave said:
> 
> 
> > Does anyone know the ratios of acid in the test solutions? Instead of paying 29.00 on ebay I would like to make my own? I imagine its just different formulations of nitric and Hcl?
> ...




I'm new here, so lots of basic questions still. 

What are the conce trations of the nitric and HCl initial solutions? Or, does anyone know of a resource here with the info?

Thanks!


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## lazersteve (Jan 30, 2012)

It's 68-70% HNO3 (Nitric acid) and 36% HCl (hydrochloric acid).


Steve


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## Lobby (Feb 2, 2012)

lazersteve said:


> It's 68-70% HNO3 (Nitric acid) and 36% HCl (hydrochloric acid).
> 
> 
> Steve




Thanks, Steve.


By the way, the info in the original posts is kept up to date by the author on his website. He's made a few changes to the article.

http://www.belleaircoins.com/how-to-test-for-precious-metals-2/


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## jimdoc (Feb 2, 2012)

Lobby said:


> By the way, the info in the original posts is kept up to date by the author on his website. He's made a few changes to the article.
> 
> http://www.belleaircoins.com/how-to-test-for-precious-metals-2/




That link says site unavailable for me.

Jim


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## Lobby (Feb 2, 2012)

jimdoc said:


> Lobby said:
> 
> 
> > By the way, the info in the original posts is kept up to date by the author on his website. He's made a few changes to the article.
> ...




Wow. It sure does. Same thing off my bookmarked favorites. Let's give it a few hours to see if his site comes back up. Else I'll delete my post. Or something.


Edit: works now. Site must have been down.


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## goldsilverpro (Mar 8, 2012)

luvmydiamondrings said:


> I've been looking around on this forum for testing info. This looks like what I need, but am still unsure. Is this for testing refined metals or raw materials or is it also for testing jewelry that has been already made (I.e. metal wedding bands or costume jewelry).



Mainly for jewelry. If you want to hang around, remove the link in your signature.


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## Anonymous (Mar 11, 2012)

goldsilverpro said:


> If you want to hang around, remove the link in your signature.


I am recomending that the account be removed.This person has not been back since the 7th,and has that same website posted in their profile..
However I would like to point out that they have a very nice ring on sale.It was $1675,and the new sale price is $1729...... :roll:


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## goldsilverpro (Mar 11, 2012)

Gone with the wind!


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## charles_dencute (Jan 12, 2013)

love you all guys...i am an unemployed person who just recently got job for an ameteur chemist here in the philippines...its nice to invest here with gold recovery...if your interested i can help you all the way...sorry this all i can help in this site,,


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## Richard NL (Mar 20, 2014)

goldsilverpro said:


> I remember an excellent article in the "Gold Bulletin", many years ago, that used a white touchstone. I think that it got heavily into PGMs also. I've tried to locate it, but have had no success.



This article ?:
http://www.scribd.com/doc/29496340/Touching-Precious-Metals-Testing

Miss Hoke did also mentioned about a white touchstone for PGMs in her book "testing precious metals"
http://www.scribd.com/doc/14426836/Testing-Precious-Metals-CM-Hoke1 Page 42 on Scribd.

Best regards Richard.


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## goldsilverpro (Mar 20, 2014)

Here's the 1st link Richard gave, as a pdf. It uses a red stone and it may be the article I was thinking about. I may be mistaken about a white stone article.


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## solar_plasma (Dec 21, 2015)

This thread would be stuff for the library - it leaves almost no questions unanswered


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## FrugalRefiner (Dec 22, 2015)

Once again, your wish is my command. 8) 

Dave


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## meatheadmerlin (Feb 10, 2017)

I too was unable to get to this site
http://www.belleaircoins.com/how-to-test-for-precious-metals-2/

So, I checked archive.org's wayback machine.
The last saved copy of it is from January 18, 2013.
I figure it is worth posting that link here.
http://web.archive.org/web/20130118...ircoins.com/how-to-test-for-precious-metals-2

Edit: full text removed due to possible copyright issues


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