# Are silver-plated stainless steel screws worth processing?



## netseeker (Aug 30, 2008)

Hello all,

I've been lurking here for a while. An excellent site. Lots of good info and some interesting personalities and opinions on this site  making for a vibrant forum. 

I've used the keyword search here with no luck. I have questions about silver-plated stainless steel screws. How hard is it to remove the sliver from the screws and is there a way to tell how much silver is on a screw. I have a lot of different sizes and I don't know if they are actually worth anything. I'll try to get some pics on here later.

Robert


----------



## Noxx (Aug 31, 2008)

I'm glad you used the search function !

But unfortunately for you, we never discussed about silver plated on silver (I can't recall).

If you have many pounds of that stuff, and you wish to recover the silver yourself, there may be a solution.

What I would do, would be to soak the screws in 20%-30% nitric acid. The acid will dissolve the silver and leave the stainless steel untouched.

After that, you can precipitate the silver into Silver Chloride with either table salt or muriatic acid (HCl). You can also precipitate the silver with Copper.


----------



## goldsilverpro (Aug 31, 2008)

If it is truly silver on stainless, and you have a lot of it, it is possibly worth while. The silver content on most material of this type runs from 1% to 2%, by weight. That is from $2 to $4 per pound. Is the stainless strongly magnetic? How much total weight do you have? Can you post a photo?


----------



## SapunovDmitry (Aug 31, 2008)

Noxx is right, but u should know that if temperature is high enough and the solution is exposed to a heavy sunlight it will start to boil and react with the nickel in the stainless leaving very very green solution(I had such a reaction taking silver from the material containing 33% nickel and 66% Fe. First it was light blue(when silver and copper underlayer were dissolved), but when it heated enough it started to boil and became dark green).


----------



## netseeker (Sep 1, 2008)

I have at least a hundred pounds of these screws in sizes from 4-40 up to 3/8" or even larger. I have them stored in multiple boxes so I need to gather them in one place and weigh them. 

The screws are made of non-magnetic stainless steel and are silver plated so they don't bind up in the screw holes due to heat and such. They are mostly socket head with a few other different types of hardware mixed in and are commonly used in the semiconductor manufacturing industry which is where I work.

From what I have been reading different metals affect each other differently - either to precipitate, alloy, etc. - but since high quality non-metallic stainless steel has not been mentioned as being used in any refining I wasn't sure what would happen if I used an acid. What Noxx said makes sense to me since stainless is pretty tough so dissolving the silver from the steel and then recovering the silver from the solution sounds like a winner. The stainless steel itself is worth money clean so I can actually have two metals to sell after processing.

I took a couple of pictures tonight but the light is bad and I'm unfamiliar with the camera so they're not very good. They are a few size examples but since you have nothing to relate to I know it's hard to judge their real sizes. I'll get some more pictures out later this week.

Robert


----------



## SapunovDmitry (Sep 2, 2008)

If you are sure that it will take off only silver then it is a great idea. Keep posting.


----------

