Test Kit

[racergold]

I have been reading a lot of posts and am still a bit confused. I have a "Vigor" test set that has three bottles, about 15 ml each, a test stone, and a set of nine test needles. When I bought the set, about 12 years ago, the bottles were(and still are) empty. The instructions for the three bottles says; #1, mix ten grams potassium dichromate salts with 3/4 oz. nitric acid plus 1/4 oz. distilled water. For bottle #2; Mix one part hydrochloric acid to 50 parts nitric acid and 12 parts distilled water. For bottle #3; Aqua regia- Mix one part nitric acid to three parts hydrochloric acid.
The instructions say what the solution for bottle number three is, aqua regia. But it does not name the other two solutions for bottles number one and two. It does include instructions for making the tests.
I know there are listings of chemical suppliers for refining, but is there a place I can get very small amounts to make up these three test solutions? Please forgive my ignorance, I have been searching and reading until I get eye strain. The Forum is a facinating read, thanks to all.

 

[Geo]

bottle #1 will be Schwerter's solution, used to test silver.Metal.

Color in one minute.
Color of mark left.

Pure silver
Bright blood-red
Grayish white

.925 silver
Dark red
Dark brown

.800 silver
Chocolate
Dark brown

.500 silver
Green
Dark brown

German silver
Dark blue
Light gray Scarcely any

Nickel
Turquoise blue

Copper
Brown

Brass
Dark brown
Light brown

Lead
Nut brown
Leaden

Tin
Reddish brown
Dark

Zinc
Light chocolate
Steel gray

Aluminum
Yellow
No stain

Platinum
Vandyke brown
No stain

Iron
Various
Black

 

[goldsilverpro]

I have been reading a lot of posts and am still a bit confused. I have a "Vigor" test set that has three bottles, about 15 ml each, a test stone, and a set of nine test needles. When I bought the set, about 12 years ago, the bottles were(and still are) empty. The instructions for the three bottles says; #1, mix ten grams potassium dichromate salts with 3/4 oz. nitric acid plus 1/4 oz. distilled water. For bottle #2; Mix one part hydrochloric acid to 50 parts nitric acid and 12 parts distilled water. For bottle #3; Aqua regia- Mix one part nitric acid to three parts hydrochloric acid.
The instructions say what the solution for bottle number three is, aqua regia. But it does not name the other two solutions for bottles number one and two. It does include instructions for making the tests.
I know there are listings of chemical suppliers for refining, but is there a place I can get very small amounts to make up these three test solutions? Please forgive my ignorance, I have been searching and reading until I get eye strain. The Forum is a facinating read, thanks to all.

I once had a set of 4 glass drip bottles that had instructions similar to yours. Here's essentially what mine said. Use 67 - 70% nitric. The hydrochloric is 37%. If all you have is muriatic (32%), use 15% more and cut back on the water 15%.

Silver test acid (Schwerter's solution) - 10g potassium dichromate + 22ml nitric + 7.5ml distilled water

10K acid - 22ml nitric acid + 7.4ml distilled water

14K acid - exactly the same as your #2 bottle. To make the measuring simpler, use 24ml nitric acid + 6ml distilled water + 10 drops hydrochloric acid.

18K acid - 6ml nitric + 6ml distilled water + 18ml hydrochloric

You should mix these as accurately as you can. However, since this is a comparison method, they don't have to be perfect.


Rather than spending a bunch of money for acids, you could probably order a set of ready-made test acids from eBay cheaper.
http://www.ebay.com/sch/i.html?_ipg=&_from=&_nkw=gold+test+acids&_armrs=1&rt=nc&LH_BIN=1

This one also has a 22K and a Pt bottle and free shipping.
http://www.ebay.com/itm/6-Gold-Testing-Acid-Jewelry-Test-Kit-Scratch-Stone-10k-14k-18k-22k-Plat-Silver-/390358062014?pt=LH_DefaultDomain_0&hash=item5ae32753be

If you're in a city, just about any jewelry supply company will carry these test acids.

For testing, this is the best guide I've seen.
http://goldrefiningforum.com/phpBB3/download/file.php?id=1765

 

[FrugalRefiner]

publius had potassium dichromate available at this thread:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=58&t=13648.

I was very happy with mine!

Dave

 

[racergold]

Thank you, all. The information is very helpful, thanks for the quick response.

 

[publius]

publius had potassium dichromate available at this thread:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=58&t=13648.

I was very happy with mine!

Dave

Thanks Dave. It is still available!

 

[g_axelsson]

bottle #1 will be Schwerter's solution, used to test silver.Metal.

Color in one minute.
Color of mark left.
...
Copper
Very dark blue
Cleaned copper
...

Thanks for the list!

I found another list in http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=562&p=4766#p4766 where Lazersteve states :

...
Copper - Brown
...

Is the difference in color depending on how the solution is prepared (several recipes exists) or is one a typo?

Göran

 

[FrugalRefiner]

The lists I have say brown for copper. If I see blue, I'm thinking nickel.

Dave

 

[Geo]

Thanks guys. I copied the list from a post on another forum. At the time, I had no reason to doubt any of it but now I think who ever wrote it was observing the nickel barrier being dissolved. I will edit my post to show the correct information.

 

[g_axelsson]

Thanks for the correction, I was copying your list in my turn... 8)

Göran