I had a local gunsmith thread  my barrel an then attach my phantom FH "permanently" with epoxy. I would like to remove it to take off my FSB, with a blowtorch melt the epoxy enough for removal purposes. Witll that damage / warp the barrel? Thanks.

Jls7

Like I said in the other post it should.

I don't think Epoxy is BATF approved to be a permanent way to attach it. It needs to be
Soldered with a MAP Torch or Acetylene.

How to Permanently attach a Muzzle Break to a Post-Ban Rifle

(assuming the barrel is threaded)

By: Scott A. Jimenez of AR15-L

One of the BATF recommended ways to perm attach a muzzle device is by 1100+ degree F silver solder.

Over in FAL land, this practice is very common with the 'smiffs.'  Recommended stuff is a MAPP gas torch ($59 bucks for a spiffy trigger start unit from Home Depot) and Fusion Silver Solder (silver solder
and flux pre-mixed in a syringe):

www.silversupplies.com
Item #56
1 oz syringe $7.95
1145 deg melt, 1205 deg flow.

Clean and degrease threads and muzzle device, apply solder paste, index device if necessary, heat device until cherry red for 3-4 minutes, Voila!  Permanently attached.  

MAPP gas will slightly discolor the park so refinishing may be necessary if you're fussy.  my particular barrel is for a beater posty 16" LW so I just hit it with CLP to make it dark again and I'm good to go.

Notes:

1) Sometimes, the threads can be such a close fit that all the solder paste gets pushed back when you thread the attachment on.  The solder won't really have much place to go so you need to create an interrupted thread in the attachment.  a Dremel with a long, round grinding stone will be fastest/easiest.  Create a few thin troughs
perpendicular to the threading inside the attachment.  This will give the solder somewhere to flow and hold if the threads are tight.

2) A way to check if you need to do this is to apply a good bit of the paste to the barrel threads, thread the attachment on, then back it off.  Is all the paste backed up on the barrel shelf where it meets the threading?  If yes, see above (#1).

3) The more you apply the MAPP torch, the more discoloration you will get.  It's gonna discolor a bit anyway.  i

4) The heat should be concentrated on the base of the attachment that is covering the threads.  Some flame will spill over onto the barrel edge but if you keep that to a minimum by adjusting and aiming your flame, you should be able to minimize discoloring on the barrel's park job.  You can do a home park job on the end of the barrel and
attachment in a cup in the kitchen, but that's a whole 'nuther DIY project.  

5) The 1oz tube of paste should be good for ~10 attachments.  Use that to estimate how much paste you should be using.

Nice stuff for the DIY'er who doesn't have the requisite tools to pin and weld muzzle devices and do extensive refinishing.  there are also arguments that even heating to only ~1200F is kinder to your barrel
than drilling, pinning, then unevenly heating to welding temps (2x the above temp??).  Whichever.  

Submitted for your approval and chock full of AR content.  Get yourself a dremel (to remove the offending bayonet lug) and you can make post-ban compliant barrels all day with this method; or attach your favorite FH to that less-than;16" barrel.

Just a side note on this process:  It's always good to keep a brass welding rod of appropriate diameter
around so that you can knock out a bead of silver if it protrudes into the bore or inside the diameter of the brake's obturator.  A quick bronze brushing with a non-plastic rod before the silver has cooled will also do the trick.

Also, a wet patch can be used to wipe molten flux mess off the barrel or brake before it burns too much or before it cools and hardens into a mess. Not using too much flux/solder mix on the threads will avoid any need for the above, but best to be prepared, eh?

Note from Rex of AR15-L: It shouldn't be necessary to heat it to cherry-red, nor to heat it so long (from Machinery's Handbook):

    Temperature  Color
    Fahrenheit  
         752             Red heat, visible in the dark
         885             Red heat, visible in the twilight
         975             Red heat, visible in the daylight
       1077             Red heat, visible in the daylight
       1292             Dark red
       1472             Dull cherry-red
       1652             Cherry-red

I work for a company that makes boom trucks for power companies.We bond the boom steel and boom fiberglassglass together with epoxy and we have had to pull some apart.What you need is a torch with a rosebud tip on it.It will cause the epoxy to breakdown.The fumes are not pleasant at all so wear a respirator It should do the job.

Thanks yall.

Jls7

Quoted: I had a local gunsmith thread  my barrel an then attach my phantom FH "permanently" with epoxy. Jls7

You're lucky not to have been caught with that setup.  Epoxy is not an approved method of permanent attachment.

Lucky? hardly, there is no way to tell that it isnt silver welded on.

Quoted: Lucky? hardly, there is no way to tell that it isnt silver welded on.

Then on the reverse, there's no way to tell that it is silver soldered on.

Quoted: Quoted: Lucky? hardly, there is no way to tell that it isnt silver welded on. Then on the reverse, there's no way to tell that it is silver soldered on.

Exactly.  I'd bet the burden of proof would be yours and with admittance that it was epoxied by your gunsmith, it's likley you'd lose that battle.

Would it ever come to that - not likely, but I'd hate to be the test case.

Its worth pointing out that they aren't known for being gentle.