Car bodywork distortion woes

[pauldee]

I've been practising for a while now. I can do nice controlled runs, get good penetration etc, but my big problem is distortion. After welding a couple of pieces of metal together the result just a wavy distorted mess.

Firstly I tried butt welding by doing a few tacks, waiting for it to cool then doing short runs, waiting for it to cool etc. However, I tried to penetration all the way along - I'm guessing this is wrong? I just read on here you're supposed to do the runs on lower setting. So is it not essential to penetrate for the runs?

I tried lap welding, but again I was trying to get penetration - is this not essential for lap welds?

By far the most successful results I have had have been with plug welding, but this doesn't seem to be a common method for car panels etc. I believe this is because it can be a moisture trap but surely this could be sorted with some seam sealer?

On the subject of plug welds, does anyone find those hole punches on joddlers make a big enough hole? I find I need a much bigger hole.

 

[Spark plug]

You need good penetration on all welds for the best result, when welding car body pannels ware distortion is an probloem tack the material about every 2 inches then let it cool then put a tack between them and let it cool.

The trick is to get good penetration on all tacks but without heating the metal too mutch. It's more patients than anything.

The reason you seam weld on a lower setting is because once the metal is hot it dose not require as mutch heat to get penetration as you are moveing along the pannel.

 

[hussy]

welding car panels does take an age on anything that isnt bent or supported,
you can tack a reinforcement bar along where your welding ive found this keeps things straight and takes some of the heat so less distortion.
what bits are you welding? anything roof or quarter based are generally a nightmare!
slowly building tacks up, go from bottom left top right,top left, bottom right and keep a pattern going.

 

[RAINSHADOW]

Question about thickness of sheet material

Nowdays all the cars/trucks have thin sheet metal instead of the great material of the 50's/60's and even 70's. How do you weld this thin crappy
stuff and not warp it ????
thanks, Rookie from USA

 

[norsa]

However you weld body panels, you are going to get distortion. Accept it and learn how to use a hammer and dolly then filler (as a skim, not as a packer)
The JOGGLER hole is usually arround 6.5mm which should be ok for panelwork as long as you get the settings right. You need a much higher setting for plug and tack than for seam as you are starting on a cold weld.
Nick

 

[Sean]

I never do a run on a panel longer than about 10mm. Its just tack one end then tack the other end slowly joining all the tacks up - I was once told to not start the next weld till you can touch the last one with a bare hand

 

[slimjim]

I've been practising for a while now. I can do nice controlled runs, get good penetration etc, but my big problem is distortion. After welding a couple of pieces of metal together the result just a wavy distorted mess.

Firstly I tried butt welding by doing a few tacks, waiting for it to cool then doing short runs, waiting for it to cool etc. However, I tried to penetration all the way along - I'm guessing this is wrong? I just read on here you're supposed to do the runs on lower setting. So is it not essential to penetrate for the runs?

I tried lap welding, but again I was trying to get penetration - is this not essential for lap welds?

By far the most successful results I have had have been with plug welding, but this doesn't seem to be a common method for car panels etc. I believe this is because it can be a moisture trap but surely this could be sorted with some seam sealer?

On the subject of plug welds, does anyone find those hole punches on joddlers make a big enough hole? I find I need a much bigger hole.

yes i find that to with the joddler, so I use a punch, one the same as this!

http://www.ebay.co.uk/itm/METAL-HOL..._Metalworking_Supplies_ET&hash=item5d35e538c1

 

[200T]

I never do a run on a panel longer than about 10mm. Its just tack one end then tack the other end slowly joining all the tacks up - I was once told to not start the next weld till you can touch the last one with a bare hand

That's how I do it (and I do nothing but car panels). Give it time to cool.Lots of time. It takes much longer to get the job finished, but the time is saved by the lesser amount of preparation needed for painting I get paid by the hour, still it's totaly acceptable by my boss. And he knows why

If it is a 'quick'n'dirty' repair, like the last oiling for the final MOT, of course you can do overlapping panels. You can hide them well when you joggle the edges. Then flood the joint with thinned down primer, apply filler, sand down, paint - seam sealer or wax from the rear side - job done.

Actually, well prepared & conserved, that's a long lasting repair method. After all, 99% of all panel joints on a car are done this way and they usually last 10-15 years at least untill they start to seperate

Welding is generally a problem when you can't get to the rear side (patching a sill or something). You can use all the zinc coated tin in the world - the weld itself is still exposed and the zinc burned away. Welding is cool, but it also brings it's problems with it.

Cheers,
Jan