Any tips for fixing a blowout on the edge of a panel when welding in a patch ?

I was welding a patch into my '38 Ford hood yesterday where someone had bent the hood by trying to shut it while the hood latch was still engaged.

The flange on the inside of the hood was all stretched and distorted, so I cut a small section of it out and bent up a new piece to put some strength back into it. It all went well until I got the edge and then the heat built up faster than I could deal with it and the edges burnt out leaving a big "bite mark" on the edge of the panel.

I was wondering what the best way is to build up the edges again. Can you use a copper backing piece with a TIG, or will the filler stick to it ?

 

Copper works really well on edges. The filler will not stick to it. I've done it with MIG in the past.

 

yes copper works good. but when i was tjg welding and i was doing real light work i would turn my miller hf 310 down at its lowest range and weld it it takes a long time to get hot but thats what you want watch your peddel control. dan

 

clamp a piece of br*** behind it. works great

 

Run off tag, add a small piece at the end of your weld, then cut it off once you're done.

 

Thanks for the tips. I'll put some copper behind it and try and fill the gaps that way.

Tysond - I had left some extra material on the patch, which I thought would help but it didn't seem to.

My TIG is fairly basic and doesn't have a remote amp control setup yet. I probably should have stopped well short of the edge and turned it down manually for the last bit, but I was getting impatient

 

Also a good way is to not weld all the way up to the edge as such, rather stay a few mm's away at the end of your bead, hold the torch there for a few seconds and let the pool work up to the edge, you have to stop it just as it reaches and not a second later. It's hard to explain. I've had some good results on think gauge.

 

back it up with a piece of aluminum and weld the end first (after the piec is all tacked in). if your using a tig the colder the better at the edge, turn the amps up after you have the edge welded in about 1/4 inch or so. use some good fill rod.

 

Yeah, I know what you mean - that is how I do it when gas welding and it works well.

 

Try holding the tungston past the work and let the arc travel backward then add a small amount of rod at the verry end.works well with thin stuff,verry low amp when doing this.The filler rod will travel toward the tungston.

 

Great tip, thanks. I tried this last night and it worked well. All fixed

 

Too late now but for next time I was taught to always work from the inside out to the edge when welding in panels.

If you have to work from the edge in, leave 1" unwelded on the end then come back and work back to the edge to keep from blowing out the edge.