Pawnbroker Bob
Active member
Here you go guys. Everything you need to know about testing metals from this months edition of Todays Pawnbroker.
Enjoy!
Pawnbroker Bob
Enjoy!
Pawnbroker Bob
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The Pawnbrokers Guide to Testing Metals
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Pawnbroker Bob
Active member
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
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
qst42know
Well-known member
Do you think a stripped 486 cpu ceramic would work for a touch stone?
Kinda full circle recycling :lol:
Kinda full circle recycling :lol:
save that bleach solution sanitizer, to recover the gold its disolving 
Pawnbroker Bob
Active member
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
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
Very smart about the disinfection procedures Bob. You continually impress me with your thoughtfulness.
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.
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.
mlgdave
Well-known member
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
mlgdave
samuel-a
Well-known member
- Joined
- Oct 7, 2009
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- 2,190
I can't find the post, it's by Harold or GSP (sorry can't remember who)mlgdave said:
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.
Richard NL
Well-known member
This article ?:goldsilverpro said:
https://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"
Testing Precious Metals C.M Hoke | PDF | Fineness | Metals Page 42 on Scribd.
Best regards Richard.
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.
The moderators would like to thank all of the members who contributed to the original thread that this post was based on, as well as those who asked questions showing what was missing. Because of the extra length and interest in this thread we have created the above, consolidated version making for an easier read. We encourage all members to read, comment, and ask questions in the original thread, The Pawnbrokers Guide to Testing Metals.
The moderators have edited some posts in this thread that made reference to posts that were deleted. We strive to make these Library threads as concise as possible by deleting posts that do not add information to the original topic. All of the original posts are still preserved in the thread listed above.
The Library threads should not be considered to constitute a complete education. Instead, they're more like reading a single book on the subject of recovery and refining. There is so much more information on the forum, and it is impossible to include it all in these condensed threads. Members are strongly encouraged to read the rest of the forum to round out their education.
The moderators have edited some posts in this thread that made reference to posts that were deleted. We strive to make these Library threads as concise as possible by deleting posts that do not add information to the original topic. All of the original posts are still preserved in the thread listed above.
The Library threads should not be considered to constitute a complete education. Instead, they're more like reading a single book on the subject of recovery and refining. There is so much more information on the forum, and it is impossible to include it all in these condensed threads. Members are strongly encouraged to read the rest of the forum to round out their education.
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