I would like to know if you can attach a muzzle break on a threaded post ban barrel and use an epoxy or JB Weld to permenent affix the the break on the muzzle.  Assuming the ATF says that this is a no-no then could I use a 45 watt solder iron to melt the silver solder at the head of the break?  Would someone please fill me in on this.
Thanks.

Post ban barrels are not threaded. [x]
No, you can not use chemicals to bond the brake to the muzzle.
No, the silver solder must be heated up to 1,100 degrees f.

You can read the BATF's letter on what they consider a permanantly attached muzzle brake.
[url]http://www-2.cs.cmu.edu/afs/cs/usr/wbardwel/public/nfalist/atf_letter40.txt[/url]

Bookmark this page, it has all of the Bardwell ATF letters:
[url]http://www-2.cs.cmu.edu/afs/cs/usr/wbardwel/public/nfalist/law.html[/url]

Finally you should bookmark this website.
Read the "how to" from the Maryland AR15 website:
[url]http://groups.msn.com/TheMarylandAR15ShootersSite/howtoattachamuzzlebrake.msnw[/url]

The Chief, Firearms Technology Branch of the ATF (Edward M. Owen, Jr.) says in a [url=http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/wbardwel/public/nfalist/atf_letter40.txt]letter[/url] that to [b]increase barrel length[/b] and/or [b]remove muzzle threads,[/b] you can attach a muzzle device (such as a muzzle brake, cap, or barrel extension) by:

1) high temperature silver solder having a melting point of at least 1,100 degrees
Fahrenheit.  

2) A seam weld extending at least one-half the circumference of the barrel, or

3) four equidistant tack welds around the circumference of the barrel

Mr. Owens goes on to say, [b]"Industrial adhesive products are not an acceptable method for permanently attaching a muzzle device."[/b]

In this letter, Owens does NOT say whether or not drilling a hole through the muzzle device into the barrel, pinning it, and tack-welding over the pin is acceptable.  It is common practice to do so (Kurt does this), and Mr. Owen might have approved such a method in another letter.  However, I couldn't find anything in writing for this.  Anyone?

I attached a couple of muzzle brakes using high temp silver paste similar to Silver Fusion by Brownells.

[img]http://bin.homestead.com/files/solder01.gif[/img]
I use a crush washer instead of a peel washer.

[img]http://bin.homestead.com/files/solder02.gif[/img]
Torch until it is dull red. Propane probably is not hot enough.  Use at least MAPP.