[Norwegian]

I've cut out pices of the firewall/dash and welding the same pice back in.
Problem: I cut away about 1.2mm ( 1/20" ). On smaller pices I've filled this with the MIG, but this pices are a lot larger.

Any idea, tested or not, on how to fill this space is welcome..


Pettersen

 

[Busted Knuckles]

If possible (doesn't look like its going to be easy), take a strip of copper sheet and tape it over the seam underneath and weld from the top. The copper will hold up the weld puddle up until it cools. Good luck.

 

[JAY221]

How about tacking in a strip along the seam location to back it? Later, Jay

 

[Norwegian]

Thank's for all the help.

I tested BK's suggestion with brass. It was not easy, but it
worked. A metal-strip in the seam tend to melt. Maybe this
is a result of my poor welding-skil..?
I tried a combiantion of this two suggestions. I placed a 1.2mm wire in the seam and welded at low currnent with a piece of brass underneath. The metal in the wire ( note sure what kind of steel ) did not completely mix up with the weld.
Is this safe??


Pettersen

 

[BillyBob1950]

I am a welder and own JMS Welding out of Mabank, TX and I can tell you that the idea of putting the "blacking plate" behind the wall is a very good idea. When filling in big holes etc. with a mig maching this is a fairly simple process...

*First set your backing plate
**GRIND GRIND GRIND. GET YOUR SURFACE VERY CLEAN FROM SCALE PAINT DIRT OIL ETC...this well make it easier for you to fill in the areas and this will help ensure that you will have a strong weld when you are finished.
*Make a tack in either end of your gap.
*Put a few tacks every inch or so apart but a good idea in doing this is to put a tack on the far right, then go to the far left, back to the far right and so on...this gives the metal a good chance to cool so you won't burn through it and lessen the chances for major warpage.
*Keep going very very slow till you got it filled
**GRIND GRIND GRIND**

If you have anymore questions private message me or e-mail me, I'de be happy to help with what ever I can.

 

[BillyBob1950]

By the way, with the two metals not mixing completely, your overall strength is diminished.

 

[one off]

there's another way that works exstreemly well. take a piece of sheet metal cut it in a 1" strip and to the length of the piece that your working on. drill 1/4" holes about 2" apart along each side of the strip plug weld the strip to your part and then to your car.it is a simple matter to fill the gap with a mig. oh you can't use brass to backup a weld and get good results copper works fine and graffite works even better.

 

[F-1Rodder]

Another trick to try is this. If you have a long narrow gap, you can take a length of gas wellding rod and lay it in the area you want to fill and then run your mig weld until you completely fill what you need to do. This also works well when you want to extend an edge. Lets say you have done a top chop and you are aligning the door seams, you can extend the door width with a layer or two of gas welding rod.