Removing silver solder
 

Is there a way to remove silver solder without changing the underlying metal temperance?

I have a WWII Hungarian Luftwaffe issued Femaru 37M, that someone has silver soldered the firing pin hole. The customer would like to restore the gun, but I’m afraid if I heat up the slide to remove the solder, I will change the metals temperance and render it unsafe to shoot

Any Ideas?


also any Idea where to get some parts

thanks
Jim :crying:

If it really is silver brazing alloy, the steel it's stuck to would need to be heated to near dull red to get it to flow, at which point it can be mostly wire-brushed off or blown off with compressed air. You'll likely still have a thin coating that remains. Re-establishing the clearances by drilling out the alloy may be your best bet.

Chances are that the solder is the simple variety. it is useless as it is, Try heating it gently till you the melting temperature of ordinary pipe or electrical solder and see if you can blow the solder out of the hole

Here is a temperature chart as a guide:

http://www.kester.com/kester-content...rt-15Feb11.pdf


(WEAR PLENTY OF PROTECTIVE GEAR IF YOU ARE GOING TO BLOW MOLTEN SOLDER OUT OF THE HOLE WITH COMPRESSED AIR!)

Lugerdoc may be able to help you with parts... or Numrich...

Or take a rod punch and tap through the firing pin channel to see if you can simply punch it out.

I vote for drill it out, not that it matters; the metal has already been heated near red hot if it is really silver solder and stuck.

It will either be brittle or soft, I would not recommend firing it at all, and for sure not much, JMHO.
Probably better left in place.

What he said. If heating it up will damage the part unfortunately the damage has already been done since someone had to heat it up to get the solder or braze there in the first place.

Best bet is to mechanically remove whatever it is and send out the part to be hardness tested. I would not know what the original hardness should be. I owned a Femaru in the 1970s. Nice looking, appeared to be a well made arm.

Jerry

It may have not been heated at all. If the intent was just to make it inoperable some after WW2 just poured hot solder into the firing pin hole and let it cool. If the surfaces were not clean and oil free, the solder would just cool in place but would not transfer damaging heat to the slide. I examined a Star Model B 9mm that was disabled just that way by the veteran that brought it home. I would test the situation by heating a nail to really red hot and touching the solder. If it melts at all with a simple touch it is soft solder and this slide can be easily saved without damage IMHO. If it doesn't melt in this test then the only way to safely salvage the slide would be to remachine the FP hole. Just my $0.02. (Again... :) )

I sure hope you guys will post the follow-up on this project....could it be an interference fit and not a metallurgical issue?

If it's mine, I will consult pullmanarms.com. They are micro-welding & micro-machining professionals, knowing what's possible and what's impossible, re-tempering is needed or not, etc. Tell them your goal, they tell you it's possible or not in a few minutes. If too expensive, not worth it, then, don't do it. Assessment is free.

One thing for sure, you don't want to play the torch for basement water pipe soldering on guns :)