Silver solder part deux

[Karl_T]

This thread https://www.hobby-machinist.com/thr...loctite-retaining-compound.86523/#post-775430


got me thinking about a metal bonding issue I have.


I got some Brownells hi force 44 solder and also some hi force 44 ribbon to try bonding a charge handle cover to a PKT receiver body. i have had real trouble with tig welding melting the cover and if this is avoided getting a good weld bond to the receiver.


I'd like suggestion on trying this silver solder. the mass of the receiver is 50 times the mass of the thin little cover. So the issue i see is getting both parts evenly at solder temp. Also the part needs to be clamped while heating and this is another heat sink. A final issue is the solder can not be visible when done or it will not blue evenly.


I am wondering about putting the whole assembly in an oven with little pieces of ribbon solder sandwiched between parts. other suggestions?

 

[Nutfarmer]

If the silver solder does run ,it can be cleaned off to blue the reciver. Would it help to practice tig welding on something else? Most welding is just practice before it starts to turn out well. I would use a hard silver solder with a high percentage of silver. Not the soft ones that are common that may only have less than ten percent. Good ones may have 40 to 60 percent. On a small welding job that needs to be perfect it may make sense to have someone who welds all the time do it.

 

[brino]

another option might be Silicon-Bronze TIG brazing, some people make it look easy:
https://www.weldingtipsandtricks.com/silicon-bronze.html

Good control is still beyond my skills.....but I need new glasses!

-brino

 

[NC Rick]

another option might be Silicon-Bronze TIG brazing, some people make it look easy:
https://www.weldingtipsandtricks.com/silicon-bronze.html

Good control is still beyond my skills.....but I need new glasses!

-brino

I have tried and used that since seeing Jody do it on his channel. It works really well. Mine is far from artistic but functional and easy to do. In the above example, I think flux and maybe ribbon would be a good way to go. The oven idea is interesting since you can control the temperature and should be good if the wide area heating is OK. If the weldment is something like 4130, I'd want to research the normalizing temperatures and make sure I was left with the appropriate material characteristics afterward.

 

[mickri]

Have you thought of spot welding it in place? I did a quick search and saw a PKT receiver where the piece was spot welded. Or drill a couple of holes in the receiver body and weld it from the backside. Nothing would be visible on the outside if you did that.

 

[pontiac428]

Another vote for spot welds. That's how stamped receiver guns have traditionally been assembled.

 

[Karl_T]

I may have to re-design so it can be spot welded. the existing rails have rivets that go under the charge handle cover, so the rails must be attached first. They are in the way of doing a spot weld. Does not work to have a thick piece of 4140 (0.125"), then a 0.060" sheet (receiver), then another 0.060" (charge handle cover) and try to spot weld the last two.

For TIG, need no welding showing on the sides of the cover. So we drill holes in the cover and tried plug welding. Just cannot get a enough heat with 5/16 holes. Went to 3/8 and then it burns out the side at least once. I am using a pro - my son - he welded for a living for two years.

Anyway, if i can silver solder, it will save scrapping several parts and re-design. Also hi temp silver solder is out - would loose the temper on the 4140.

 

[Flyinfool]

If your part fit is correct and the ribbon is the correct size shape and thickness then the put it together in the oven will work fine. Don't forget to use flux. Although some guys have been hurt badly trying to use the oven in the kitchen, Beware of wife's wielding frying pans.

As with heating anything with a torch it comes down to learning how to concentrate the heat on the heavy part to get it real close to temp and usually the small part will just come along for the ride.

 

[Karl_T]

Thanks for the vote of confidence. i will give it a try.

many years ago, the wife left for shopping. So I put welding rod in to dry in her oven. It had some grease on a few pieces and smoked the house. i was in the dog house for a LONG time.

Guess what, i now have my own oven - just a $25 garage sale electric unit.

 

[pontiac428]

For clamping three layers of steel and applying spot welds, this comes to mind. Also can use a steel block as a heat sink on the back side where the thin metal is. You could even MIG weld it and file/machine/grind flat so no spot welds show.