Butt welding help

[iwlbcnu]

Using a Lincoln Mig Pak, Argon/Co2, can't get a nice smooth weld, can only hit it and let off as soon as I get a ball or it burns thru, just have to keep hitting it as soon as the glow is gone, is this normal? Switched to .025 wire and seemed to help from .030, played with heat and speed. Wondering if the butt is the real problem.
Also, should I push or pull the weld? I can't get a push to work. Unless really thick metal, I have a hard time getting a smooth low profile weld. A grinder ends up being my friend.

 

[Revelation]

If you are welding thin stuff, like body panels, you will need to "stitch" weld.

 

[Dave in Houston]

Butt Welding

Revelation is right. If you're welding body sheet metal (18 - 20 gauge) you have to stitch weld it, which is basically doing a bunch of "tacks" until you finally get the joint filled. Even if you can get it to weld a smooth bead on thin metal it will get too hot and warp like crazy anyway. Welding body panels is a real pain and takes a LOT of practice to get it right.

 

[getfuzzy]

push to get a good penatration. pull for less penatration and to fill gaps. and yes you need to spot and move to another area of the part and on and on.

 

[bigbadktm]

i like to pull my bead, provides a nice clean weld, but we have all been where you are now. its no fun esp. if there is any rust on the metal

 

[iwlbcnu]

When I try to push I just get build up on my existing bead, guess I'm not moving quick enough. Looking back at my pics, think alot was not a uniform gap.

 

[Skiddy]

yes you will have to skip weld it and pulling will be a lot better, welding thin stuff like that is kind of hard. on the larger gaps you will just have to weave it back and forth, just keep at it until it is all sealed up

 

[Dave]

First, I would clean up the joint a little better. Welding through that paint isn't doing you any favors.

 

[tk1218]

Cleaning both surfaces is very important. I have a cheap HF Mig 90 with flux and I have had good success on Min power at wire speed of 4 out of 10. If you move fast you can lay down a good bead without burning thru.

 

[Skiddy]

First, I would clean up the joint a little better. Welding through that paint isn't doing you any favors.

but the paint helps spatter clean off better;D yes a clean surface is a must especially with mig

 

[JHD]

what are the copper/black plugs?

 

[hmh800]

They're Cleco's. Used for holding 2 panels together. THey have little fingers on the end that expand to grip the metal. There is a special pair of pliers used to compress them to insert into a 1/8" hole.

 

[iwlbcnu]

Actually I do have a bevel on the edges, no sense cleaning back anymore when you are just trying to fill the gap, right?

 

[allenfahey]

Most bodyshops use .23 for welding but .25 should work OK. As said before you need it clean, on the mating side as well as the new metal (ecoat grinded off). Spray a light coat of weldthru primer on each mating surface. If the new metal is laying on the old metal you want holes in the new peice and fill the hole. You probably will have to grind the weld some what flush. That's normal. I see what your doing on the seams but you still want to grind away the paint some more.
You don't want to weld the whole seam up. Tack weld every 3" or so. When your done prime and sand the seam on both sides top and bottom. Then put some seam sealer on prior to paint.

The shop I work at has a sweet spot welder that welds like the factory does called a "Pro Spot". It welds right thru paint and e-coatand no grinding needed but is 30K.

 

[allenfahey]

One more thing..... the mating surfaces needs to be flush to the underlying metal. The Clekos might not be good enough. Obviously visegrips used for welding won't work for the floor. Small self tapping screws are what alot of bodymen use then they weld the holes up or use seam sealer.

 

[borg]

Practice, practice, practice

And from the looks of that door post you're going to get a lot of it!

Steve

 

[iwlbcnu]

The e coat Allen mentioned may have been part of it, I didn't think I had to clean new metal. Or just practice as todays patch worked pretty nice.
I also amusing alignment clamps from Eastwood to make the butts mate, and did pull down the plugs with screws.
Luckily only the bottom of the post is bad, hope to splice it. We'll see. This is practice for later projects.

 

[Broncitis]

I generally run .030 or .035 but use .023 for body panels. One thing I have found is that the drive roller pressure is much more critical on the .023.

Too high and it will birdnest and cause several minutes downtime to restring the wire.

Too little and the rolls will slip and is will cause an erratic feed that will sputter, spit, and cause the ball to burn back up the wire away from the puddle.

As I believe was pointed out, if plug welding (I usually use a pnumatic body punch then plug weld to the panel behind during panel replacements, flush butt welds pretty much just on panel patch repairs), it is critical to have the panels tight against each other at the point of weld. I found a couple styles of nice specialty clamping pliers for this. One has copper fingers on one side and a solid copper disc on the other. These can also be used to fill a hole in a panel as well as clamoing around a plug weld. The other had steel fingers on both sides and there are long enough and spaced so you can clamp a few spots at a time.

I have some little butt weld clamps that I think I got from Eastwood that have thumb screws that hold them. I only tried them once or twice and thought they were somewhat of a PITA at the time. I usually use vise grips with swivel pads and/or weld magnets.

 

[Mark]

I wouldn't weld the seams at all.
for floor pans, plug welds and seam sealer work well.