welding tips?

[mwc]

hi all,
this post is kinda related to a post on the mg42 gen disc on "invisible" rewelds......i just wanted to hear some tips from others on how to set up for the best weld w/ minimum of cleanup.....
i know tig is best and most precise, but i think most diy'rs prolly have a mig setup....
with that in mind, i'll throw out the following for discussion:
-gas w/ mig is ideal (of course tig if you got it), and though flux core will work....the sheer fact that gas mig welds are far easier to cleanup, and the lack if smoke and splatter while doing welding makes the chore far easier....
-clean slag and degrease the base metal so there is no chance of contamination. bevel the ends of the pieces for good up/down penetration of the weld....
-a good tight fitting jig/weld backer underneath the weld joints.
-preheat the pieces to be welded w/ a propane torch for good fusion...

am i on the right track for good weld outcome? thanks all...

[Karbinator]

Sleeve copper behind your gap intersections, so your weld buildup/splatter cannot
overwhelm the interior as much, and create Hell for you to get out. I'd say not to
grind out the torch slag at first. See if you can knock it off with a wire wheel on a
bench set up so you can get some pressure...this way you can use every nook/cranny
of decent usable metal the reciever has to offer for your connection.

[mwc]

thanks karbinator,
i think ive got the heat range and wire feed rate down pat for good fusion, and the backer looks to me minimizing cleanup on the backside......

[Daskraut]

This is the reason you should not use oxy-acyetelene, esp when you are first generation walking upright in your family....like me. Pull-in was a real problem, maybe a piece of metel down the length would help keep the receiver straight. Wavy as the sumbitch is, it was great fun to do.

[TOM R]

I see you got the pics to work that looks good , with a tiny bit more fill and clean you would never tell it was cut

[Daskraut]

Tom, u-da-man!. I hear ya on the fill, but with the heat needed ,it warps and cracks....so "f" it, blueing hides all!!.You have no idea how bad I wanted to braze to fill!. :twisted: