I won about a pound of this type of aviation computer pin gold plated scrap on eBay, it is in the mail right now. A rough estimate based on surface area tells me that there should be several grams of gold in this lot. I payed about 60 dollars with shipping. Did I get a good deal? Here is a link to the auction in question: http://cgi.ebay.com/ws/eBayISAPI.dl...witem=&sspagename=STRK:MEWNX:IT#ht_1617wt_936
I bought some scrap on eBay
- Thread starter lasereyes
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samuel-a said:
There is a picture of a few pins next to a ruler, so I guesstimated the surface area based on a 1/2inch long cylinder with a 1.5 mm thickness. I did a rough estimate of how many pins there are in the picture, then used the methods on this forum to estimate gold content. I think the plating's grade could be millspec.
samuel-a
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we'll be smarter once you finish them...
milspec.... don't fall in love with this term, this is mainly a fleebay promoting "power word" for scrap...
There are lot's of civilian applications that use thicker plating then some military applications...
once you receive the pins, digest a sample in nitric acid (50/50) and see if there's one complete foil left after digestion or is it brakes apart into gazillion pieces... this will help you ballpark the plating thickness...
milspec.... don't fall in love with this term, this is mainly a fleebay promoting "power word" for scrap...
There are lot's of civilian applications that use thicker plating then some military applications...
once you receive the pins, digest a sample in nitric acid (50/50) and see if there's one complete foil left after digestion or is it brakes apart into gazillion pieces... this will help you ballpark the plating thickness...
Barren Realms 007
In Remembrance
lasereyes said:
You might consider slowing down till you know what you are doing. And take the suggestions of the forum members. It will save you a lot of grief and headaches.
Barren Realms 007 said:
Well I think it will work out alright, but I don't think that I can justify the cost of nitric acid when nitrates are so much cheaper. Money can be tight some times, especially while going to school, so this seems like an ideal hobby that also has a potential to deliver a return on investment.
You can process a small sample of the scrap with 35% H2SO4 (battery acid) and NaNO3 (nitrate of soda, sodium nitrate) to get the base metals out leaving the foils behind.
The process is the same as Modified Poorman's AR, except you use sulfuric acid instead of muriatic. The solid sodium sulfate (by product) rinses out of the gold foils with hot water.
No need to buy technical grade nitric for the test.
Steve
The process is the same as Modified Poorman's AR, except you use sulfuric acid instead of muriatic. The solid sodium sulfate (by product) rinses out of the gold foils with hot water.
No need to buy technical grade nitric for the test.
Steve
lazersteve said:
Unfortunately I do not have any sulfuric acid around to do this sort of test. The hcl that I bought was from ace hardware store. Am I correct to assume that drain cleaner would be suitable due to its sulfuric acid content? I think I have seen it at lowes.
NAPA auto parts carries the 35% stuff for batteries, cost is around $15 for 5 gallons. It's very clean compared to the drain opener.
ACE carries the Rooto acid drain opener, but it is in the high 90% concentration so you can dilute it (1:3, acid:water) for the test.
Steve
ACE carries the Rooto acid drain opener, but it is in the high 90% concentration so you can dilute it (1:3, acid:water) for the test.
Steve
lazersteve said:
Sounds like a good deal, but a shame, since there used to be a napa store about 10 blocks from where I live, but it closed a while ago. I will look around for the drain opener and report back here with the test results soon.
qst42know
Well-known member
Lowes was expensive $32 for 2.5 liter box. Check other auto parts stores. OReillys (Murray's) also carries battery acid. They had it in stock 5gal box for $25, I didn't price the smaller container.
Here's the meat of a 'Dry poor man's nitric acid' reaction.
I can post the long version of this post with math and equations if anyone wants to see it.
The Reaction:
I can post the long version of this post with math and equations if anyone wants to see it.
The Reaction:
- Place 50 grams of copper based scrap in a 1.5 Liter beaker.
- Cover the scrap with 253mL of distilled water.
- Add in 253g of anhydrous NaHSO4 (sodium bi-sulfate) and cover with a watch glass.
- Heat the reaction to 100C.
- Allow enough time for the NaHSO4 to dissolve completely.
- Reduce heat until temperature is 90C.
- Slowly add 10g of NaNO3 (sodium nitrate) being careful of foam overs.
- Cover and allow to react until all red-brown fumes are gone and no more fizzing is seen.
- Repeat steps 7 through 9 until all of the copper scrap is dissolved, you should not add over 180 g of NaNO3.
- Reaction is complete when the gold foils float freely when stirred. A white powder may also be in the bottom of the beaker (Na2SO4).
- The solution will turn dark blue from dissolved copper sulfate crystals (CuSO4).
- Pour off the blue solution while still hot.
- Add in 700 mL of water and bring to boil.
- Heat until all of the white powder (Na2SO4 = sodium sulfate) dissolves and the gold foils are free of white powder.
- Pour off the liquid while hot, don't pour off any of the gold foils.
- Rinse with enough water to remove all traces of blue and white powder.
- Process the gold foils as typical.
lazersteve said:
Does it also work to just dissolve the gold in solution with a portion of the base metals in poor mans AR, or is removing all of the base metals necessary? Also, is it ok to use poor mans AR at room temperature or should it be heated?
This is not for gold, it is for base metals.
I always heat the reactions.
I can't guarantee results for those of you who choose not to follow the directions as given.
Steve
I always heat the reactions.
I can't guarantee results for those of you who choose not to follow the directions as given.
Steve
It will work for any base metal that dissolves in nitric acid.
The numbers given are for copper based scrap, adjust according to base metal type molar mass relative to copper and it's respective nitrate compound formula.
Steve
The numbers given are for copper based scrap, adjust according to base metal type molar mass relative to copper and it's respective nitrate compound formula.
Steve
