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The Great War (1914-1918) Forum

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Any metallurgists out there?


dutchbarge

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I'm trying to find a method of removing silver wash from a brass base metal belt buckle that won't poison me or burn down the casa. I'm told a 2 to 3 minute immersion in 1 vol. concentrated nitric acid and 19 vols. conc. sulphuric acid (heated to 175 F) followed by an immediate swilling has been recommended, but I can't see bringing that toxic mix into the casa, let alone heating it up on the stove. My wife just wouldn't understand. Any other ideas? Cheers, Bill

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That sounds similar to the aqua regia which is required to dissolve gold. Gross overkill! Silver is a reactive metal and something much milder would suffice - the problem being to limit attack on the brass.

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QUOTE (Phil_B @ Nov 14 2008, 09:29 AM) <{POST_SNAPBACK}>
That sounds similar to the aqua regia which is required to dissolve gold. Gross overkill! Silver is a reactive metal and something much milder would suffice - the problem being to limit attack on the brass.

This is exactly what I thought, especially as much of the brass is already showing thru the silver wash. Perhaps media or water blasting might be the ticket. Thanks, Bill

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I'm trying to find a method of removing silver wash from a brass base metal belt buckle that won't poison me or burn down the casa.

DIY - you also risk poisoning the local populace. Where will the waste product go ? Take it to a manufacturing jeweller who will have all the proper kit and know how to do it.

Owen Hales

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Dont ever ever ever think of going near either concentrated sulphuric or even worse nitic acid. Live with the silver plate. Have you ever seen a sulphuric acid burn, I have!!

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Thanks all for the great advice. I've emailed over a US dozen firms and no one is interested. Can anyone recco a frim in the UK? Once it has been stripped I'd like to have it gold washed. Cheers, BIll

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DIY - you also risk poisoning the local populace. Where will the waste product go ?

Owen Hales

Hello Owen, Just down the road from Santa Fe we've got WIPP (Waste Isolation Pilot Project). Thought I'd dump it there along with the depleted uranium, plutonium and misc. scrape of the nuclear arms/power generating industry.

JUST KIDDING! No DIY on this project!! Thanks for your input. Cheers, Bill

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Dont ever ever ever think of going near either concentrated sulphuric or even worse nitic acid. Live with the silver plate. Have you ever seen a sulphuric acid burn, I have!!

I've seen phosphorous burns. You're right. No DIY on this one. Cheers, Bill

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Bill.

I once removed silver wash from a buckle using a dremel kit and a small buffing wheel and grinding paste (Automotive finishing grade) use slow speed and doing small areas at a time, then I finished the piece off with jewellers rouge and a large buffing wheel on a small bench grinder then took in down to parent metal which was brass, it was time consuming but it did work. I must add that most of the silver wash was worn off the piece before I started, and it was a pretty plain. But in all probability this would not work on a piece with a lot of fine detail.

Cheers Rob

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Hello Im a metalurgist and have worked with these chemicals PLEASE DONT DIY you have a strong possibility of burning yourself or poisening the local water course.

Just go to a good jewlers they will be able to do it and it will be cheaper then you buying the correct chemicals and safety gear with no mess to you.

Nim.

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If the item was silver plated I believe you can reverse the process by electroysis.

GB

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We used to handle conc sulphuric and nitric acids at school without any protection. The sulphuric appeared to have no effect on the fingers but the nitric left a brown colour and the top layer of skin peeled off. No long term effects. That was before H&S arrived. It wouldn`t have been pleasant if splashed into the eye. 10% nitric was habitually used in industry as an etching agent for steel, again without protection, and never caused any effects. Maybe we were lucky!

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QUOTE (Phil_B @ Nov 18 2008, 11:19 AM) <{POST_SNAPBACK}>
We used to handle conc sulphuric and nitric acids at school without any protection. The sulphuric appeared to have no effect on the fingers but the nitric left a brown colour and the top layer of skin peeled off. No long term effects. That was before H&S arrived. It wouldn`t have been pleasant if splashed into the eye. 10% nitric was habitually used in industry as an etching agent for steel, again without protection, and never caused any effects. Maybe we were lucky!

The stuff used in schools (which I can also remember) was pretty dilute (but still a hazard to the eyes) about the same strength as battery acid.

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The stuff used in schools (which I can also remember) was pretty dilute (but still a hazard to the eyes) about the same strength as battery acid.

No. It was available as dilute and as concentrated which came straight from the carboy as delivered and marked up as such. When you poured it into water to dilute it, the water got quite hot. Some of the chemical reactions wouldn`t have worked with a dilute acid.

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Phil Conc. sulphuric and nitic acid will remove skin from your fingers, and fingers from hands but at least you were taught to add acid to water. I once saw water added to nitric by a student !!! NICE super hot nitric shower.

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Cardinal rule - acid to water! Surprising, thinking back, that they allowed students (even at university) to do those things without eye protection. Most lab coats had holes in them from chemical splashes. I suppose, fortunately, we didn`t have the concentrated acids on our fingers for long before washing them off, as we realized it wasn`t a good idea to spread it around. We also used to breath in large amounts of H2S from the Kipps apparatus used in chemical analysis in those days, and carbylamine from one of those tests for primary amines. It`s amazing we made it through!

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Do as you aughter as acid to water was the thing I had drilled into at school,

Concentrated sulphuic acid from what I remember was like a syrup, very thick. Like glycerine with a slight yellow tint.

Came in Moles for strengh 0.5, 1.0, 1.5, 2.0 strongest we used as I think 3.0, I did my GCSE coursework on the reation time between different moles and magnesium.

Gaz

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So,Gaz.Your a blimmin mole torturer now,is it? :o

you cad.

Bill,why not save some effort & just gold plate over the silver?

If that isn't practical,whoever plates it for you will/should be able to get rid of the silver if it's necessary I would have thought.

Happy Klondiking,Dave.

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You should use weak nitric acid (3-5% or 0.5-1M) and warm it gently (say about 40C) and allow it to steep for a while; you'll probably see the silver flaking off rather than dissolving. At this concentration you should not damage the brass, although it would be a good idea to do a spot test. Note: here in the UK concentrated nitric acid is 72% by weight - 15.8M (and I don't suppose its any different in the States as its all made by the same process). If you can get it from your chemist (drugstore) then probably best to get them to dilute it for you.

Do not use sulphuric acid (battery acid) - it will create a deposit of silver sulphate which will just make a mess.

Do not use hydrochloric acid under any circumstances - it will definitely go with the brass.

To get rid of the spent nitric acid just add domestic baking soda until the mixture stops fizzing. You can then safely pour it to a domestic drain.

I used this method to clean up some valve inserts that had been silver plated - it works.

Andy.

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Do as you aughter as acid to water was the thing I had drilled into at school,

May her rest be long and placid

For she added water to the acid

Completely forgot that we had taught her

To add the acid to the water !

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Bill.

I once removed silver wash from a buckle using a dremel kit and a small buffing wheel and grinding paste (Automotive finishing grade) use slow speed and doing small areas at a time, then I finished the piece off with jewellers rouge and a large buffing wheel on a small bench grinder then took in down to parent metal which was brass, it was time consuming but it did work. I must add that most of the silver wash was worn off the piece before I started, and it was a pretty plain. But in all probability this would not work on a piece with a lot of fine detail.

Cheers Rob

Hello Rob,

The buckle is very detailed and just as you mention I don't think your otherwise great suggestion woulod work in this instance. I'll put it on file though and use your method somewhere down the road. Thanks! Cheers, Bill

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Bill,why not save some effort & just gold plate over the silver?

Dave.

Hello Dave,

The long answer: I've got a silver washed Prussian officer's feldbinde and need a gold washed one to complete a uniform ensemble. The buckle is a very rare one (Hessen). It took me 14 years to find it, even thought it was not the finish I needed. Originally, pre 1915 buckles started as bare brass base metal and were either silver or gold washed as needed by the regiments. By removing the silver wash and adding a gold wash I'll end up having a mil. spec. buckle. If I apply a gold wash over the silver it won't be exactly correct.

Short answer: I'm a driven, overly fussy git who never allows himself to do things the easy way even when no one is watching.

Cheers, Bill

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Thanks one and all. As usual there is no question that is beyond the collective wisdom and experience of the Forum. Discretion being the better part of valor I've found a commercial jewelry operation that will strip and gold wash the buckle for a modest price. So not damage to me, my family or the environment. When the project is done I'll post a photo of the results. Thanks again! Cheers, Bill

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Hello Dave,

Short answer: I'm a driven, overly fussy git who never allows himself to do things the easy way

Cheers, Bill

Just seen this,Bill.

The word now used is not 'git'.It's 'anorak' :lol:

Dave,another 'waterproof'.

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