Brownells sell's a couple solders for this application. An preference over the 475 deg or 650 deg Hi Force solders they sell. Could also go to silver solders however they flow at about 1150 degrees.

This hi force solder really flows well...but I've had a problem, maybe the guys can help.

It seems that the solder wants to "crawl" from under ribs, sights, etc. I clean with bead blasting, boiling water, detergent, baking soda and the damn stuff still wants to discolor at the joint when rust bluing.


Any of you had the problem...how did you cure it?

From a long-ago industrial engineering class: coat areas you do not want solder to stick to with french chalk, i.e., welders soapstone, not the talc variety. I have been "told" that Whiteout typing correction fluid works but cannot verify.

My guess is the discoloration you experience is from microscopic amounts of lead, tin, and/or silver in the pores immediately adjacent to the joint inhibiting the rust process.

Thanks...beginning to suspect the flux may be part of the problem too. Once heard that old timers used lemon juice for flux to avoid a "bleedout" from between ribs, etc...the longer I screw around with guns, the less I seem to know

Duane,
It IS the flux. I now flux and pre-tin the parts seperately, then scrub well in hot flowing water to remove all traces of the flux. Then re-assemble, heat, and voila. You don't need flux the second time around as both parts already are tinned. I've found that the only way to stop the creep problem that you're having is to boil the part for about half an hour in a strong solution of distilled water and baking soda. The baking soda seems to neutralize the acid and the creeping stops.

I've been using rosin for flux after tinning the parts with Swif paste. The rosin is just crunched between my fingers and sprinkled after the joint is filled.

Gunmaker,
You bring up a very good point that I've been wondering about for a while. I know that rosin works well with low temperature, tin/lead, or tin/antimony solders. Do you have any personal experience with using rosin as a flux with Brownell's Hi-Force 44 solder which flows at a considerably higher (475F-500F) temperature?

The discoloration is flux creeping out of a void in the joint from temperature changes(boiling, cooling). A few cycles of boiling and cooling in a baking soda bath should get it out. A spray of carburator cleaner first should get most of the flux out.