re-soldering a front sight

[smallpatch]

I need to move the front sight on a very thin smoothbore barrel.  That part I can handle.  The problem is, the barrel lug(opposite side of the barrel) is only about 1 1/2" behind the front sight. I'm concerned that in the process of relocating the front sight, that the underlug will move as well.

Clamping is difficult because the barrel is round at this point.

Any help??

[California Kid]

Maybe try to put the barrel in a vice, holding it with the lug section in the jaws, using the vice as a heat sink. You can get heat stop at a welding supply as well. The vice worked for me though on a recent fowler build. Had the same scenario.

[Dave Faletti]

If you only need to move the sight a little just heat the sight and not the barrel.  If you are relocating it use a small clamp of any sort on the underlug to act as a heat sink. 

[Dave B]

I have become fond of using soldering coppers for doing soldering jobs lately. I will run across them from time to time and when the price is right one will follow me home. I did some under rib work using a large copper slug attached to a steel shaft to keep the heat up on a thin barrel during the sweating process.  Using the copper that is turned to sub barrel dia. or even cut to have a half round shape would be even better. This provides the heat exactly where you need it and no where else.  I use my fire brick forge made from two fire bricks with a cut out section for the heating of the copper.

[JCKelly]

Brownells sells a product "Heat Stop" which one plasters over the area meant to stay cool. It absorbs heat so your soldered underlug won't fall off. Today I think they are out of stock.
That copper bar is probably the best idea.
Not sure but what a potato might work also. As a heat sink.

[Don Getz]

Jim beat me to this one........use a potato, amazingly it works..............Don

[Robby]

I set it on a wet napkin with the end of the barrel hanging over the edge of my bench. As long as there is steam coming off the napkin, it wont break the solder. Same idea as the potato I guess.
Robby

[alex e.]

I set it on a wet napkin with the end of the barrel hanging over the edge of my bench. As long as there is steam coming off the napkin, it wont break the solder. Same idea as the potato I guess.
Robby

I clamp my sight sight from the top. then put a damp cloth on the under side.it took me a while to figure out as most French guns have their sight laid out almost over the lug.It does not take too much to keep  the lug cooler.

Alex

[northmn]

Some wrap the part to remain secured, like the lug, with a radiator hose clamp before soldering.  Seems to work.

DP

[smallpatch]

OK, it worked, here's what I did.
I first used a piece of tie wire to secure the underlug.

Then clamped the barrel in the vise with aluminum vice block at the point of the underlug.  Then just un-soldered/re-soldered the front sight.  Worked great.  The aluminum vice block worked as a heat sink and everything stayed where it needed to be.

Thanks for your help guys.