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
The Pawnbrokers Guide to Testing Metals
- Thread starter Pawnbroker Bob
- Start date
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qst42know
Well-known member
Great post. Thanks Bob
Pawnbroker Bob
Active member
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
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
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:
macfixer01
Well-known member
Thank you for the post!
macfixer01
macfixer01
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.
Juan Manuel Arcos Frank
Well-known member
Thank you,Bob...vey nice book
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
Fournines
Well-known member
Cheaper...
http://www.ajstoolsonline.com/mystore/test-stones-1.html
http://www.ajstoolsonline.com/mystore/test-stones-1.html
samuel-a
Well-known member
- Joined
- Oct 7, 2009
- Messages
- 2,190
mlgdave said:
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.
mlgdave
Well-known member
Awesome! Thanks!
mlgdave
mlgdave
jimdoc
Well-known member
Thanks for bumping this thread, The Pawnbrokers Guide to Testing Metals needs to be seen by all newbies.
No thanks on your spam.
Jim
No thanks on your spam.
Jim
jimdoc
Well-known member
samuel-a said:
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
Acid_Bath76
Well-known member
Pawn Bob,
Thanks for the PDF!! It's just what I was looking for!!
--AB
Thanks for the PDF!! It's just what I was looking for!!
--AB
Dirtdiggaler
Active member
- Joined
- Jan 23, 2011
- Messages
- 38
Great read! Thank you for posting that.
Lobby
Well-known member
samuel-a said:
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!
