Body welding: warping to be expected?

[Carpe Discus]

I'm going to pay someone to weld a patch above my rear raingutter. I'd do it myself, but although I'd love to learn I don't weld and would prefer to learn on something different (and I don't really want to store a welding rig).

The guy I asked about it is not a "body guy", but rather a "welding guy". That is, his bread and butter is generic welding, not bodywork.

He warned me to expect some warping of the sheet metal (and as a result some filler will be needed). I know this is possible, but is it inevitable? If I go to a (presumably more expensive) body shop, is it going to be warped, too? I know there are techniques to minimize warping of sheet metal when welding, but I don't know if it's worth paying a lot more for someone who welds less frequently, but mostly sheet metal in the hopes of getting a better result.

 

[PHAEDRUS]

I have never seen someone put in a patch panel with any welding process without having to use some filler.
Dave

 

[tobydog]

Short answer

Short answer yes

 

[cruiser88]

Find someone else. Any warpage up top is unacceptable

 

[okie]

a good welder that does body work will leave no warpage to the eye. those guys are expensive though.

i found a highschool kid with alot of experience and he took his sweet time and it turned our great. little warpage.

again there are guys that can do this with no warpage or close to none but they are expensive..

yea find someone else. you shouldn't be using bondo to hide it.

 

[Weedhopper]

My reading says that you have to go slow so the metal does not get too hot. A hit on the left side, a hit on the right. Then the middle. Slow and easy.

 

[MiniMan85]

To properly weld body panels, you have to do 1/2" sections at a time, allowing it to cool for 1/2 minute or so before going back to that area. Generally a 1/2" section will be welded, then you skip ahead 2-3", weld another 1/2" strip and continue doing so until you get to the end of the area to be welded. Start again at the end of the first weld and repeat.

 

[p7teb7]

To properly weld body panels, you have to do 1/2" sections at a time, allowing it to cool for 1/2 minute or so before going back to that area. Generally a 1/2" section will be welded, then you skip ahead 2-3", weld another 1/2" strip and continue doing so until you get to the end of the area to be welded. Start again at the end of the first weld and repeat.

i just recently got done w/ school for auto body (what a joke, but that's another story) and that is the way that they instructed us to weld panels, rails, etc. The fact of the matter is that you have to have someone with allot of time in welding auto body panels specifically to avoid warpage and reduce the amount of filler work. some warpage can be expected regardless, and as a result, some filler work. the amount of filler is what depends on the welder.

 

[Hugh Heifer]

Find someone else. Any warpage up top is unacceptable

X TuT. I recently talked to a car guy who was trying to get something sandblasted and asked the guy about warpage and blow thru. Guy said probably not but maybe. He went with it and got both. I have a guy who has been blasting for years and only blows through the most rusty of panels. I liken that to a body welder.

You should find somebody else.

 

[Nomis]

If the panel gets too hot, it expands and "sets" in its expanded state which equates to a warped panel as the expanded metal has to go somewhere and bows out. The metal can be shrunk back into place with heat - usually from a torch and some metal work. A good welder/body man should be able to minimize warpage and then shrink metal when needed to get it as close to straight as possible. Would some filler still be needed prior to paint? Maybe, but this doesn't mean that the metal work is "bad". In the end you want a solid flat panel, a good body man should be able to get you that. My advice is look at some samples of their work and base your decision off of that IMHO.

 

[Texx]

Warpage won't be a major factor in a rear sill replacement due to the small surface area of the piece being welded in. It's a much bigger problem on rear quarters, large pieces like that.

 

[brownbear]

the metal above the gutter is quite thick. All cruiser metal is.

I'm a novice and can weld with out warpage.

Some filler will be needed.

spotweld it on, working side to side spreading the heat out. Using a damp cloth and cooling the metal also helped me. using a hammer and releasing the metal after welding helps too.


Another option is to not weld. The glue on epoxies work just as well. basically you glue a flush patch on. It lasts much longer than a weld. Welding on the roof is going to rust again. Glue might not.


When you glue with the structural epoxy you cut out the area, then glue in a lip piece all around. Then cut a piece to fit inside and voila.

There are some instructionals on this if you need.

 

[kulangot]

Ron Covell can weld with out warpage and do patches with out bondo.

For the rest of us, we use "Covell in a can", otherwise known as body filler AKA Bondo.

The trick is to use as little filler as possible.

I have pulled off a few patches with out any filler but it is VERY time consuming. I usually have to use some here and there. Nothing wrong with

Best to mark out 1 inch increments, tack weld on the marks then fill in the gaps with one little tack weld at a time.

See attached pic.

-Stumbaugh

 

[photogod]

I did this top with a Mig welder and .025 wire, gas shield. I welded the edges with a spot every 6 inches and then went back over with a continious bead. I did all the sides and then did the arches on each end. I am a s***ty welder but I got it done with zero warpage by going slow and spacing out the welds. 20 ga. sheet stock on 16 ga. supports.

If I can do it a blind monkey can do it!

 

[kulangot]

Cool Trailer.

I agree, it's really not that hard and you made a good point - .023 or .025 wire is key! The thinner wire acts like a resistor and puts less current (heat) through so that there is less warping.

Pretty much, if you caulk your bathtub and make it look decent, you can Mig.

-Stumbaugh

 

[chicago]

Cood thread...
Im just beginning to pracitce, gearing up for a rear quarter chop, and some rust abatement...
I had some sheet metal lying around to use a scrap and Im starting with that...
A few questions to get it to come out decent...

1) Is it best to TACK a bead, run a bead, or run 1" beads to limit the heat? There are a couple of different opinions above.

2) Is using gas going to produce the cleanest panel?
Right now, I am not running gas, but will get it if its going to make all the difference.

3) does anyone know the gauge sheet metal that LC's have?

What Ive done so far has been tack weld a bead to make the seam, but I had not tried 1" incriments. Even with tacking and cooling with a damp cloth, the metal "angled" at the seam (\/)...Not quite that extreme, but you get the idea! Also, I was welding two FLAT pieces butted together!

I took a couple of pics if you all are interested, I can post em up!

Thanks,

Im really wanting to learn how to do this effectively!

Chicago

 

[chicago]

BTW, Im going to be dura-lining the work afterwards, but I do want to do as clean of a job as I can!

Thanks,

Chicago

 

[Walton]

When you are welding the metal actually gets thicker...we call it shrinking in the sheet metal trade...with practice you can stretch the metal back out with a hammer and dolly to take out the warpage...especially with a butt joint. Another technique is spot shrinking to take out high and low spots.