The Stovebolt Site Forums The Shop Area Paint and Body Shop Welding in patch panels

I got my patch panels in for my '49 Chevy Truck cab. I am patching the cab corners and the outer crowl area. I am getting mixed opinions on how to weld them into place. My plan is to use those small interlock clamps that create a .040" gap in the seam to weld up. then grind the weld down smooth. This to me seems the best way to avoid minimum body filler.

One person tells me I cant do it like that you have to over lap the seams. This way sounds like when you grind down the weld you will grind it away plus will have to use more body filler to feather the seam out.

Then there's the butt weld. but again seems you will grind away you weld were it wont hold.

Iam using a Millermatic 135 Mig welder with co2 as my shielding gas. So which method should I use? Is there anther way?

Thanks !

I find overlap joints just tend to collect water /moisture. Have also seen modified vise grips that will creat a lip the same thickness as the patch panel to help make welding easier (but you still have a lip). All of my welds are full (not spot) using .032 in the mig (requires less heat) and argo mix (agron/co2) some gas supplers sell it as autoweld or such..

I just finished my cab corners on my truck. I flanged (used panel flanger from the Eastwood Company) the side of the cab and then welded it in from there. It required harldly any filler and looks really good

mall - i tend to think like albert.. the seams i've done with the gap seemed to reqire less filler & less grinding and look less noticeable than overlap, I also use 75/25 CO2/argon. never tried straight CO2. I think my book says to use straight argon on aluminum. Hope it goes well for ya!

After I had done mine as flanged, lap joints I read a post here that mentioned a problem I hadn't thought of: The thickness of the lap joints affects expansion & contraction rates so when the truck is parked in the sun the seam becomes evident.
My next one I'll do as butt joints and I see those interlock clamps as being real handy for doing it.

The mixed gas is far better but my supplier will only fill those tall bottles. I dont have a great setup shop wise to handle that type of bottle. The short co2 bottles are much better for me. Plus I own a restaurant and have the co2 already in the bottles for our soda machine. Since your useing a bunch of spot welds then grinding them down why have them look purdy to start with?

Mallard,

Didn't you build a rotiserrie for your cab? Sounds like you are having a lot of fun! Go with the .040 gap and let us know how it goes. Pictures?

Hi Gang

I just replaced my cab corners on my 1ton 53 chevy.
MY thought where welding the in to place, but when I talked to the local Chevy body shop I was told that they would glue them. Yes Glueing is the latest technology. Any non structual parts the glue into place. Since my welding is not the best I went the new way, Time will tell. You can see some pictures on my website,
The product I used comes from DURAMIX which is now owned by 3M.

Ken yes I did build one and it worked great. I got tons of picture I need to get developed and posted some place. Ill let ya know when I do. Thanks with the help!

I'm kinda ignorant about this stuff ... can anybody tell me if you could use (bronze) BRAZING to attach patch panels? Its for bonding steel to steel and I understood one old man to tell me that it would work fine for patching rusted out jeep floors. :confused:

Mallard,
go for the butt weld or the joint with a small gap, I prefer the butt joint, a gap of any size will cause more distortion, a nice tight fit is best but you dont want the two edges pressed together with any pressure as this will also cause distortion.I agree with the others on the overlap, it just invites moisture and rust.as for GMSea's questions on the braze.stay away from that stuff. for one thing paint doesnt stick to it to well and alway manages to create rust around the brazed area. and the fumes from brass are real nasty and will make you sick in a hurry.