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strategic braze removal with mercury dissolution/amalgamation

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joe kozak

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#1
Have an old #2 "army" S&W somebody brazed the latch and hinge shut. (because it stretched?) This is a wall-hanger, will remain a wall hanger, but would be nice to have it be openable.
Thoughts on the procedure of removing the braze rod filler by dissolving into mercury amalgamation?
Might be able to separate under heat with oxy torch, but would have to mechanically remove the braze filler anyways from parts. Anyone know what metal these 1860's revolvers might be made of... steel type, high/low carbon, full iron, nickle/iron, because mercury wont normally attack Iron, but might attack the alloying metals.
Research points to being able to get at least a 30% copper mix into mercury but I find no mentions of how long a solid surface piece might take to dissolve, insomuch dentistry amalgams use a powderized metal dust and goes quickly into solution.
 

joe kozak

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#4
looks like slightly concentrated (10-20%) ammonia water will dissolve the copper out without affecting the iron as long as it stays basic and not acidic. does not look like there are any other purpose-added steel alloying metals from that era to dissolve either. and per http://www.eng-tips.com/viewthread.cfm?qid=273391 "Carbon steels in anhydrous ammonia service can suffer from stress corrosion cracking if the water content is less than about 0.1%, with the presence of oxygen (also small ppm). "
 

markba633csi

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#5
I would stay away from the mercury approach and probably use heat and a metal bristle brush to remove the braze
Mark S.
 

dlane

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#6
Wounder if somthing like solder wick would work
 
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