silver solder gas

[tat]

Will mapp gas or propane melt silver solder?


Thanks

 

Oh heck yes,low temp silversolder works fine that way.

 

[Bountyhunter]

There are numerous grades of silver solder.

The low temp solders melt at about 400 degrees.

I use mid range solders that range from 900-1100 degrees for silver work, and they do ok with propane.

There are some higher end solders that do better with mapp or acetylene.

I use different solders in the silver work, putting the highest temp solder on first and as I add pieces, go to lower temp solders so I dont melt off the first pieces.

Bill

 

[tat]

Thanks,

I guess I also need to ask what % silver should I use. I will be using it to weld my breech plug into my tang. The back side of the breech plug will is an unthreaded 5/8 shank and I have drilled the tang 1/2" deep to slide it in and then solder it.

Thanks

 

[Vaino]

Either weld or braze it...Fred

 

[WRussell]

Gee, I would have thought silver solder (silver braze) would be OK. Easy-flow & such are pretty strong.

Maybe we should clarify (again) that there is "silver solder" that plumbers use for copper pipe, which is low temperature stuff and not all that strong, and there is "silver braze" which is high temperature stuff, much stronger. Silver braze used to be called silver solder with no problems until the laws changed and plumbers had to use silver bearing solder which has now become commonly known as silver solder, meaning we now have to refer to the high temperature stuff as silver braze.

The only problem you run into when silver brazing with propane is heat getting sucked away by big parts. A breech plug - tang assembly might be a little marginal, but if you have problems you can pile some asbestos siding or fireplace brick around it to hold the heat in. The temperature is high enough with propane, it just lacks in btus/calories. Mapp works better.

 

[tat]

Thanks,

The local welding supply will ask what % of silver solder. What % is the silver braze? or is there another name they may know it by? I would like to know incase I decide to use it.

Thanks

 

[Stophel]

Buying a ready-made breechplug would be SOOOO much simpler. :winking:

 

[WRussell]

Tell them what you're doing. In other words, I don't know and it doesn't matter a whole lot for what you're doing. You just want strong.

 

[CoyoteJoe]

I've used lots of the low temp silver solder, stuff premixed with flux and dispensed from a little syringe. Works great for stuff like front sights or underlugs on a round barrels, even ribs on a halfstock. You can put the solder right where you want and only where you want. Turns out to be not so expensive since there is not waste and little mess from excessive flow. But those applications offer a lot of surface for solder to adhere and relatively light loads to bear. To hold the tang on a breech plug, well I can only say, I've had bronze joints fail in that application. :grin:
Now if you have a really good mechanical fit of parts, such as a hook breech, and only need to hold the two together, even JB Weld will work.

 

[crockett]

If you are talking silver brazing then I think Mapp would be the minimum. I tried silver brazing with propane and the metal never got hot enough the melt the rod. On the silver brazing the metal penetrates the steel and makes a stronger bond than a weld. I believe the Nascar cars are silver brazed and NASA uses it (I think).

If you are talking about soft soldering with a non-lead solder (silver/tin mix)- that melts at about 430 degrees and a propane torch is fine, in fact overheating the parts and burning out the flux is the biggest problem.

I think soft soldering with the non-lead silver/tin has a bearing force of 5,000 ft lbs or something like that whereas the silver braze is 80,000 ft. lbs.

So, silver braze is called silver soldering

and

soldering with a non-lead silver/tin is soft soldering.

Go figure

 

[Zonie]

Not to be picky, but the strength is not measured in Ft. Lbs, it is measured in pounds per square inch.

Normally I wouldn't point this out, but it has a great deal to do with this post.

Because the value is in pounds per square inch the area of the joint is very important.
If the joint is a simple butt joint and is 3/8 wide by 3/32 thick, the area of the joint is .375 X .093, or .035 square inches. That multiplied by the 80,000 value equals 2790 pounds.
This 2790 value is the tensile strength, or, the force it takes to pull it apart with a load applied perpendicular to the joint (like pulling on it).

For sideways loads (shear) it is weaker by a factor of more than 2 which means a sideways load of 1395 (or less) will break it.

According to my information, the tensile strength of Silver is actually about 22,000 PSI. This value changes the results of the above calculations to a tensile force of 767.25 pounds will pull it apart and a side load of 383 pounds will break if off.

zonie

 

[WRussell]

Which points up another useful feature of silver soldering: if a load of several hundred pounds is put on your rifle barrel, would you rather have the tang break off of have the barrel bent? Designing in weak spots can be useful.

 

[Stophel]

I haven't yet figured out exactly why this is being done to begin with. First off, it seems like an awful lot of trouble, second, you need that tang to tighten the plug in the barrel. It needs to be SOLID. I figure any kind of solder you use, you may well end up twisting the tang right off. Brass braze MIGHT be strong enough to hold, but again, why bother? If you're just interested in making your own breechplug, I personally would much rather cut one out of a solid piece of steel (or forge it out, if I had that capability). To me, at least, it just seems as if you would be wasting a lot of time and effort on something that doesn't require it.

If you are still intent on doing it, I would perhaps suggest cross pinning the "tenon" portion of the threaded piece.