Gunsmithing silver solder tips

[MTFalconer]

I'm not very good at silver soldering. I can do it and end up with a good result but it takes a lot of work after the fact. I usually add way too much and polish off the excess. Can you guys give me some tips that might get me a little more competent?

 

[LRI]

Make sure all surfaces are completely sterile.

Leave a little scuff on the mating surfaces. Solder likes a "tooth".

Tin your parts prior to sweating. This is important because it'll promote the solder to flow under the parts and provide complete adhesion.

Use the right flux.

Brownells has a SS specific flux now. Haven't tried it yet, but its supposed to be pretty good.

I like my flame slightly acetylene rich so that I'm not inclined to scorch parts from too much O2. Heat management is also critical to avoid scorching a part or cold jointing them. Spend your time warming up the bigger piece first, then transition to the smaller/thinner one. Avoid corners as they are heat sinks. You want even heat and just enough to promote good capillary action. Too little and it's a cold joint. Too hot and you can scorch stuff.

Good luck. Hope this helps.

 

[MTFalconer]

Thanks for that. I had not been tinning the parts before joining. I was heating the joint, fluxing and adding solder. It has been working but the end result leaves something to be desired. I have a friend that is a master and I have watched him do it time and time again and cannot duplicate what he does. I am using a paste flux designed for silver solder and a solid silver wire. He produces a joint that needs no attention or finishing. It is perfect the first time most very time. He tells me to keep practicing...

 

[lngrng]

Silver Solder

As usual, Chad offers great advice in the interest of helping others....................lots to learn from you, Chad! Thanks once again.

 

[Turd in the Pool]

I haven't tried tinning when silver soldering but I suspect it works. It's a must when soft soldering. Seems like it would be an issue with silver solder. Guess it's all in technique.

Assuming you are talking bolt handles and the like, Brownell's sells a ribbon solder that works great. You can cut it to fit the footprint of the handle. Grind/dremel the mating parts clean (like Chad says) flux both parts clamp and heat. It's a breeze. Cleanup is nil ;-)

 

[19Scout77]

Buy a tig

 

[Turd in the Pool]

Buy a tig

Got one. But there are times ss is the only option. Like shotgun bbl lugs where the metals are dissimilar. ;-)

 

[Gene Poole]

I'm familiar with "tinning" as it applies to electronic soldering; basically melting solder on each piece separately (where electronic solder is mostly tin). Is this the same with gunsmithing? Do you "tin" with the same solder you will be using for the final job or does 'tin' actually refer to tin (the metal) solder?

 

[Turd in the Pool]

I'm familiar with "tinning" as it applies to electronic soldering; basically melting solder on each piece separately (where electronic solder is mostly tin). Is this the same with gunsmithing? Do you "tin" with the same solder you will be using for the final job or does 'tin' actually refer to tin (the metal) solder?

You've got it. A thin coat on each part will promote a solid joint. And yes, use the same solder. I've reattached many ft sight ramps with no rebluing required. Silver solder is another animal.

 

[cal50]

You need parts uber clean and a good flux , the rest is pretty basic and falls into place.

A neutral non oxidizing flame works for me. Flux the clean parts then apply heat. When heated some flux will boil out of the joint but just take your filler wire / rod and heat it , dunk in flux and swipe some on the part where it boiled out. You want a slight amount on the surface that you can see. Once you get the parts heated up and depending on the flux the flux will begin to flow out . Silver braze (depending on your selection) starts to flow over 1100F so once the flux starts to flow you are usually close. I like to dab the wire on the part to gauge the temp and once it starts flowing feed the wire and move the torch around the joint.

Low temp solders do not like excessive heat and tend to ball up and run off like water if too hot. If you are working on stainless steel and get it too hot it will turn black and is oxidized. If this happens let it cool and re-clean the parts becasue the solder / braze will not adhere to the surface. If you want to clean rock hard flux on a part boil it in water or quench it in water before it gets cool off. Heat the larger part with the torch and feather the smaller / thinner part to control temp and bring them up evenly.