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Siver solder/brazing Question

3K views 10 replies 7 participants last post by  rugman59 
#1 ·
What's the deal with silver solder and parking solution? I soldered up some parts and they were tight as could be. Then I parked them and they literally fell off!
I know the stuff is used to sweat double shotgun barrels together, so it's supposedly strong stuff. Never seen a parked double shotty, so I'll bet I already answered my own question.
Does the phosphoric acid eat the darn stuff?
 
#4 ·
I cut down a double barrel shotgun down to stage coach 18.5 inches. I then stripped the blue and parkerized it. It didn't come apart. Sounds to me like the flux was holding it together and the solder didn't bond correctly.
 
#5 ·
I can't say what specific type the solder was. Got it from Airgas. Gonna check if Brownell's has some. Gotta be the right type from them!
The flux was hydrochloric acid. Never heard that one, either?
 
#6 ·
Sort of odd what happened... I have parked many items silversoldered together without a problem.....
also I am not sure about doubles being silversoldered together many of the old ones were tinned and lead soldered together..... even the rear sights on the old Mausers were tinned and lead soldered on.....
 
#7 ·
I can't say what specific type the solder was. Got it from Airgas. Gonna check if Brownell's has some. Gotta be the right type from them!
The flux was hydrochloric acid. Never heard that one, either?
Sounds like you got a soft solder of some type. CNKILLERCLOWN probably nailed it when stating that the flux was what was holding everything together on your first try.

Get Silvalloy ribbon silver solder and Ultra Flux if you are ordering from Brownells. Silvalloy melts at about 1200 degrees F and Ultra Flux is a paste that stays in place in temps up to 1600 degrees F. Be sure to have some way of putting light pressure on the joint as you heat it, otherwise there will be voids. The nice thing about silver solder is that you don't have to "tin" both parts like you do with soft solder. Just flux both surfaces, sandwich the tape between the parts, jig up the parts so there is light pressure and they can't slip, then heat the largest part the most. If one part is thin like a shotgun barrel, be especially careful to heat that part only as much as absolutely necessary so you don't char the finish inside the bore.
 
#8 ·
I've used Silvaloy and paste flux several times and it worked very well. I think Silvaloy melts at 1145 degrees F and flows at 1205. Test it at that temperature and the solder will not release. Remelting it requires an even higher temperature. Something wasn't right if your solder released at parking tank temperatures. No way that was anywhere over 210 degrees.
 
#9 ·
What happened was that I soldered the thing up, then parked it. Stuffed it in the safe for almost two weeks before I had the chance to test fire it. The frikkin magwell fell off the first round. When I reached down to pick it and the magazine up, the gun slipped in my hand. My palm knocked the forward finger guard clean off!! I've done some crazy physical stunts, but come on!!!! LOL!! :rolleyes:
The metal grip was the only part that 'partially' stuck. I Watched the solder flow. Saw it sucked into the joints. Even 'pulled' it with the torch in a couple spots.
I don't get it.

I suppose I'll have to pop for the good stuff from Brownell's, dammit. Geez, that a hunnert bucks just to keep from warping yet another tube into an 'old man's johnson' again. Brazing is just too hot in that area.
I even bought a tiny 'Little Smith's" oxy/acetylene torch just for that.
Still too damn hot. It went bonkers when I brazed the magwell this time. I've fabbed a big-azz mandrel for just such an occasion and it worked. Reheated the beast to a nice semi-orange and STUFFED it over the mandrel fast. Sweet. Got a chunk of copper to tap it off there.
When I finally get the whole thing together, I think it would be best to shove it into the oven overnight to stress relieve it. One version that was SOOO close being done cracked halfway around the diameter in the middle of the cocking slot. GARBAGE. This is the seventh attempt. And I don't even have free metal recycling here! :D
 
#10 ·
Doesn't sound like any silver solder I've ever used. My intro to silver soldering came in a wire and cable shop. I was kinda astounded when I was told that wire got soldered together tip to tip only... no twisting, no overlap ... nothing. Just tip to tip. And by the Jesus, it never came apart. Never broke at the joint or failed in any way. If that wire broke, it was on virgin wire... not at a soldered joint. My stuff is running around on fighter jets and several nuclear subs. (We made kinda neat cables...)
 
#11 ·
I said screw it, and went ahead with the brazing. It did just what I expected. Limp d---! LOL!
Did the heating and forming thing on the mandrel a few times and got the warp almost totally worked out. Just a tiny ways to go now. I picked up some silver solder paste flux and tried it on an extra chunk of tube and a formerly good grip frame. The flux wetted out nicely!
The solder welled into a ball and rolled right off. no contact whatsoever with the metal. WTF. I think they mixed up some non-cored lead crap in the package. It's much too pliable in the hand to be silver alloy. I have lead/tin solder that's stiffer. BS.

Oh yeah. I found a super reasonable source for the brass wire I've been using. About three bucks at a hardware store. I think it was 10 or 15 feet. HA! :D

"Tip to tip"?? That's pretty amazing. I never would have guessed.
 
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