little patch

[962porsche]

1969 camaro has a rust hole in a strange place they don't tend to rust .
i cut out the area to find a mouse nest inside the rocker

i took the piece i cut out and traced it out on a piece of sheet metal using a sharpie marker.

the kerf of the cut off wheel blade is just about the width of a sharpie marker so when you cut out your patch piece cut it on the outside of the sharpie marker line .

coat the back side of the patch piece with weld primer . when it comes to using weld thru primer you do not need a heavy coating of it a thin coat is all that is needed . to much and you will get a bad weld . let the weld primer dry for a few hours to let all the solvents evaporate . i personally like brushable weld primers more then spray types .

hole the patch piece in place i tend to use a magnet for this .

place a tack weld and let it cool ..if you feel any heat do not place your next weld until it's cooled back down . work your welds spreading them out around the patch piece .

once all your welds are done it's grinding time to smooth out your welds . this i do with a 24 grit flap grinding wheel . the reason i like to use a flap wheel for grinding welds is they do not build the heat a none flap wheel does .
when your finished you should need little to no plastic body filler .

[Tom '74 911]

Nice write-up 962porsche!

Here's some little pieces I made up to fill in some holes in the floor pan & rear seat back area from a previous owner's roll bar I think. The holes were a little too big to fill in w/a MIG, although I probably could've made that method work too. I'm not a pro/for profit shop, so I don't always chose the fastest method, but usually the one I'd either like to experiment with or that I'm most comfortable with.

Kind of tedious to cut out a bunch of pretty small circles, weld a short piece of TIG rod onto each one so I could hold them while MIGing them into place. I didn't take finished pics yet...

[962porsche]

those little holes are a PITA aren't they .
to make the little round hole patches like that using a press punch works pretty well .

[Puma]

On the same line, what's the largest hole that can be welded by backing with a piece of copper and filling in?

Thanks for showing us how to do larger patches. I've got quite few spots to do on my car.

[962porsche]

i tend not to use a backer for welding up holes bigger then 1/4" or so at that point the hole becomes to large and a patch piece would get used .

[Puma]

Originally Posted by 962porsche

i tend not to use a backer for welding up holes bigger then 1/4" or so at that point the hole becomes to large and a patch piece would get used .

Thanks for the info!

[3literpwr]

This might be a possible technique for my quarter edge instead of replacing the entire panel. Thanks!