Welding tube inserts

**bamacpl** · 04-09-2009, 04:21 AM

Anyone got any tricks to keep the threads from shrinking so much while welding tube inserts? Without using a tap......They are 1 1/4"-12 Jonny Joints & a tap that size is very expensive!!!!!

**henrym** · 04-09-2009, 04:23 AM

I'm no expert, but I expect one thing to do is weld as fast as you can with as much current as you can manage. and weld a little bit at a time after everything is tack-welded.

high travel speeds with higher heat would reduce total heat input to the part.

preheating the parts being welded would probably reduce distortion as well.

**rhett** · 04-09-2009, 04:25 AM

try oxy/acetylene sweating the weld. like silver soldering copper tubing joints.

gas welding will distribute the heat more evenly reducing distortion.

of course the applications strength requirements and base material will dictate the actual process that can be used.

as henrym stated, preheat will help allot. also having a plug threaded into the the insert while welding, then removed before the metal cools off (important)

good luck
Rhett

**rhett** · 04-09-2009, 04:35 AM

bamacpl, knowing a little more now I can give a better suggestion.
find an 1 1/4" x 12 threaded bolt, the heat treated "Johnny Joint" should not be used because it will loose its heat treatment properties.
thread the bolt into the adapter, align the adapter into the tubing for welding.
preheat the bolt, adapter and tubing evenly before welding.
weld
Remove bolt immediately after welding before materials cool down.
that should do it, the bolt is the trick to help minimize distortion.
Rhett

**woofer456** · 04-09-2009, 04:36 AM

Just inserting a bolt during the welding process will keep it from shrinking, but don’t remove the bolt until it has cooled, this worked for many years building boilers.
Bob