PDA

View Full Version : Question on the pin and weld method



223to45
02-08-16, 13:39
I am familiar with what ATF list as ways to secure a muzzle device.

But a local gun smith says they been using this method, which is why I asking, is it legit?

Instead of a pin, then thread the MD and use a set screw, then instead of welding, they fill it using JB Weld.

Just wondering?

SC-Texas
02-08-16, 14:45
Wow

www.AtomicLabRat.com

Auto-X Fil
02-08-16, 15:23
Permanent methods of attachment include full-fusion gas or electric steel-seam welding, high-temperature (1100°F) silver soldering, or blind pinning with the pin head welded over

https://www.atf.gov/file/58196/download

So no, JB Weld is not OK.

SC-Texas
02-08-16, 15:24
Like I said. Wow

www.AtomicLabRat.com

Mr blasty
02-08-16, 15:46
Actually, what about silver soldering in a set screw? That would make it easier to remove than using a drill or cut off wheel.

Sent from my SM-G900T using Xparent BlueTapatalk 2

223to45
02-08-16, 16:50
https://www.atf.gov/file/58196/download

So no, JB Weld is not OK.
Yeah figured so, just want to make sure.

Sent from my SM-G900V using Tapatalk

Got UZI
02-09-16, 11:52
I just picked my jaw up off the ground. What is so hard about the concept of "pin and weld" that he does not understand? Permanently attached must only be for shits and giggles.

The silver soldier is an idea but again its not supposed to be easy to remove....that is the whole point of pin and weld.

Mr blasty
02-09-16, 12:02
I just picked my jaw up off the ground. What is so hard about the concept of "pin and weld" that he does not understand? Permanently attached must only be for shits and giggles.

The silver soldier is an idea but again its not supposed to be easy to remove....that is the whole point of pin and weld.

But the ATF allows silver soldering the threads of the muzzle device so why not a set screw. Much easier to remelt

Sent from my SM-G900T using Xparent BlueTapatalk 2

Joelski01
02-09-16, 12:12
It ain't supposed to be easy...

Mr blasty
02-09-16, 13:28
It ain't supposed to be easy...

Keep in mind that pinning and welding only takes me about 15 minutes. As for whether it's supposed to be easy or not, it's only supposed to be legal, easy doesn't even factor into the equation for if it's OK or not.

Sent from my SM-G900T using Xparent BlueTapatalk 2

BLACKMAX1
02-09-16, 13:34
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
02-09-16, 14:00
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?

Sent from my SM-G900T using Xparent BlueTapatalk 2

BLACKMAX1
02-09-16, 15:39
"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
02-09-16, 16:56
You can get JB weld in the paint department at Home Depot...so no its def not permanent.

Gunfixr
02-09-16, 18:45
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.

Sent from my SGP612 using Tapatalk

MistWolf
02-10-16, 03:28
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