Question on the pin and weld method

[BLACKMAX1]

From what I've heard the silver solder method will ruin the barrel. My local gunsmith threaded mine with a with a set screw and welded over it.

[Mr blasty]

From what I've heard the silver solder method will ruin the barrel. My local gunsmith threaded mine with a with a set screw and welded over it.

Why would it ruin the barrel?

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[BLACKMAX1]

"There are two types of silver solder, low temp (around 600 deg) and hi-temp (around 1200 deg).
Since the Batfe requirement for silver solder is that it must exceed 1100 degrees, you are supposed to use the 1200 degree stuff.

The heat treat damage floor for chromoly steels is around 1100 degrees.
100 degrees above that and you are surely beginning to anneal the barrel steel.
At 1600 degrees, the steel will be fully annealed.

Add to the fact that most people won't know the difference between 1200 and 1400 when heating up a piece of steel and you have an even larger likelyhood of fully annealing the muzzle of the barrel while silver soldering a muzzle device on it.

Now, will the barrel be damaged to the point of negative results from being annealed?
That's a whole different topic of discussion..."

Quickest response I could find from an old thread on here. Pretty much what I heard from a gunsmith.

[b2dap1]

You can get JB weld in the paint department at Home Depot...so no its def not permanent.

[Gunfixr]

1200 degrees will definitely soften steel. Not to mention, if you are doing this at home, you're going to ruin whatever finish is on both parts.

The whole idea of "permanently installed" is that the average gun owner cannot easily remove it, or remove it without creating extensive damage.
Obviously, just welding it on means cutting it off.
Solder with a melting temp over 1100 degrees will not be melted with a home propane torch, and is quite difficult to get loose with a mapp gas torch running a vortex head on it.
Blind pinning and welding is normally done with at least a 1/8" pin. This means that if you just wring it off, you will be trying to drag the broken end of the pin through the threads, all the way off. It will be quite difficult, and beyond many owners, from a lack of ability to grip the barrel or muzzle device, or both well enough to apply this kind of torque. Welding it over makes the end difficult to find, and therefore harder to just drill out. Often, when welding such high carbon steels, hard spots are created, which cannot be drilled with a regular bit. You will need a Carbide bit, which is not sold at home depot.

For myself, I usually drill and tap for a 6-48 scope mounting screw, bottom tap the hole, tighten the screw in until the head wrings off, which is usually flush, and weld it it, then dress smooth, leaving a small imperfection showing, so that the customer can show evidence if asked. It will be on the bottom.

For the home Smith, pinning and welding presents the easiest method to get a legal job, with the smallest likelihood of ruining any parts of the gun, and the best overall job, appearance-wise.

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[MistWolf]

Silver soldering ruins the steel because the solder permeates the steel to form the bond. The heat opens up the pores of the steel and the solder gets sucked in permanently. If the soldered parts are separated and an attempt is made to solder it again, the joint will never be as strong because of the solder already permeating the steel. It cannot be repaired by welding for the same reason.

The BATF has defined what methods of permanently attaching a muzzle device to a barrel are acceptable. I don't think silver soldering a pin was one of them