Aaarrrgh, well, I finally came across rust on my California High Desert SS. Seems that there is a small, quarter size hole on both sides directly behind the wheelwell (on the horizontal lip of the 1/4 panels). I now have a Lincoln 125 MIG which I plan to use to patch the panels. What kind of weld should I perform, and how much extra metal around the rust spot should I cut out to make sure it doesn't come back? I think I can get away with leaving the outer body skin intact. Should I also use the weld-through primer to keep corrosion down? Any advice would be great! Thanks in advance.

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Tony Nausieda
1970 SS 396-350hp
Frame-off Resto: Just Say No! 4 years and counting...

Unless you are describing something else, I believe they are suppose to be there. They should have rubber plugs in them. The factory used them as drain holes when the "dipped" the body. That's exactly what I discovered on my '70 when doing rust-out repair--only mine had the little rubber plugs still in them.

I'd love to hear more input if anyone can confirm this.

Hey Joe,

I know the plugs you're talking about, but these are definitely rust holes. I'll try to shoot a pic of the rusted areas to clarify what I'm trying to describe.
Basically I'm wondering how much metal to cut out, and how to weld the patches. Gonna buy a scrap fender tomorrow to learn on.

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Tony Nausieda
1970 SS 396-350hp
Frame-off Resto: Just Say No! 4 years and counting...

Tony, I have the roughly the same rust and a little bit down low on the front pass fender and also need the same instruction....Thanks for asking this question....Mark

Tony -

This type of rust starts from the inside and works its way out, so you're probably going to end up with a patch fairly larger than the visible hole. I did a similar repair on a front fender for my 68 (with the same welder - nice unit). I would suggest stripping all the paint from the rusted area, then cut around the rust with a minimum 1-inch border. When that piece has been removed, you can inspect the backside of the piece as well as the remaining metal to see how far the rust has spread on the inside. You will see pitting there - your objective is to cut until you're into unpitted metal, i.e. metal that has its original thickness. If you try to weld in a patch where the metal is thin due to rusting you will probably burn holes in the panel. And you will probably have rust return to that area.

When you have your rust cut out, you can then fabricate a patch and butt-weld it in.

I have a picture of the 68 patch on my website (link below). Check out the size of the patch necessary for a "quarter-size" hole!

And yes, use the 3M weld-thru primer. Good luck!

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Rainer Seitz
Vancouver, WA
Team Chevelle Gold #50
ACES #3784

'68 SS396
'70 LS3 400 Malibu
'70 Malibu convertible 350/300hp
and the latest - '70 Malibu 454!

See them all at the all-new Rainer's Hot Rod Shop! (http://rseitz.homestead.com/main.html)
rseitz@chevelles.com

Hey Rainer,
Good advice. I checked out your web page and had a question about the clamping of the fender patch. Did you get away with using just the two vise-grips at the lip of the fender? I practiced some butt welding tonight (just bought this welder a month ago, still learning) and I had a hard time keeping the patch from distorting due to heat. I'm asking because I'll probably only be able to use one vise grip since there isn't a lot of room in the 1/4 panel area. Was considering tack-welding, starting near the clamp and moving outward, and then filling the gaps after area has cooled.
BTW, can you give me an approximate starting point for current and wire speed settings?
This is much appreciated! Take it easy.

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Tony Nausieda
1970 SS 396-350hp
Frame-off Resto: Just Say No! 4 years and counting...

Hey Tony -

Sounds like you're headed down the right track. I clamped the patch in several other places as well as the two shown. Clamping not only keeps the patch in the right place, it also aligns the two pieces of metal so their surfaces are flush, i.e. one is not higher than the other. Eastwood sells some mini clamps that align the panels and create just the right gap between them. Another option to keep the panels aligned is to use a heavy magnet centered across the joint if you can't clamp. I'm sure the veterans have some other suggestions as well.

Remember that each time you tack the patch, you're creating a "permanent clamp," so you want to tack it around its entire perimeter (do the corners, then the centers of each side, then split those tacks 'til you have tacks every inch or so. Then you can connect the tacks with weld beads. Make sure you don't weld in one area consecutively (e.g., don't go around the perimeter in a circle, but alternate from one side to the other in a criss-cross pattern, like you'd tighten lug nuts, so each area has a chance to cool to minimize warping). Also, use a wet rag to cool the panel regularly, especially after running each of the beads.

Re: a starting point, I can't recall exactly, but with .025 wire and an Argon/CO2 mix I think a setting of around E 4.5 worked for me. Best bet is to take some scrap of the same gauge and fine tune your settings. Also, if you can cut your patch out of an old scrap body panel you'll be better off because you'll be matching the exact gauge as well as the type of steel that's on your car. Good luck!

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Rainer Seitz
Vancouver, WA
Team Chevelle Gold #50
ACES #3784

'68 SS396
'70 LS3 400 Malibu
'70 Malibu convertible 350/300hp
and the latest - '70 Malibu 454!

See them all at the all-new Rainer's Hot Rod Shop! (http://rseitz.homestead.com/main.html)
rseitz@chevelles.com

One thing more,using a non ferrous metal as copper bar will help with the stitch welding as the copper wont stick to the weld and also draws the heat away from the panel,warning: it gets hot rather quickly http://www.chevelles.com/forum/eek.gif
HR