Body work welding? Tips n Tricks Please!

[ReQuieM]

Hi all.

In the process of welding up the windows on a panel van and I'm having a few difficulties. i was hoping some of you on here might be able to share some tips and tricks to make the job easier? Its a 1mm sheet to the body, I'm using a Tig with a 1mm collet, 1mm tungsten, about a 7 cup and 1.6mm filler rod (can't find any 1mm). Oh and I'm using a pedal for control.

Ok so to start with I've fkd up and raced ahead with out doing a perfect fit up (frustration etc) so I have a few gaps of up to 3mm I guess and a couple of lap joins instead of butt ups. Yup I know I have made the job twice as hard. Any tips on how to bridge the gaps with out excessive heat? Any tips on smoothing a lap join down (besides weld, grind, bog)?

Next issue is the warping. Whats the best way to avoid it? I have about 4-5 spots that I'm going to have to beat out from behind in attempt to smooth out. I've NOW decided to tack about every 2-3cm and then I'm welding tack to tack, missing the next space, then the following tack to tack etc. is this the best way? should I add extra heat to do a run quickly or run it cooler and take alot longer?

Also whats the best way to 'fix' the warping? heat gun and hammer?

I'm finding that the area is incredibly sticky cos of the low heat and I'm constantly having to heat my filler rod off the metal and the actual tungsten (I know it shouldn't touch but its an aukward angle to work at.). Any thoughts?

Heres my progress so far (one end), note there are a few longer runs there that I found tended to warp the area...
http://i58.photobucket.com/albums/g2...anny/SoFar.jpg

Also here is a hole that blew out behind the cup while I was welding so I didn't see it until I stopped that run. Do I need to patch this or could it be saved with filler?
http://i58.photobucket.com/albums/g2...Panny/Hole.jpg

Any help would be much appreciated.

Cheers!

[wilbo666]

Linked pics for you





Cheers
Wilbo

[ReQuieM]

Thanx Wilbo, But I actually choose to have links instead to save peeps bandwidth and to keep the post semi coherent. No biggy, but thanx for trying to help any hoo

[5000gt]

from my past experiences with sheet metal welding is that you can never take too much time.... the slower, the better in terms of prevention to warping.... Also, you can't avoid having to use a grinder...

Do you have space behind for a brass heatsink at all? It also helps with blow through.

Other than that, avoid continuous seams. It takes a butt load longer, but i do like to spot weld sheet. I get little to no warp at all, nothing a skim of bog wouldnt fix at least. I have no experience with Tig sheet welding.... i can still manage with the Mig.

["Z" UTE]

Hi there, the local panel beaters have literally given up welding large sheets of metal to cars.

They now use a 2 part adhesive. When mixed and applied you have half an hour to adjust final fit, and then use a couple of screws in pre drilled holes to keep it in position till the goo goes off. The residue is not the easiest to sand off, but it can be done. The only welding is to fill the screw holes. Visit your local panel supply shop for the gear.

If you can cut your sheets of metal and allow room for decent overlap, that does not look out of place on the inside of the PV, then this method will work fine for you.

If you need to persist with the welding, to minimise the distortion hold a large piece of aluminium alloy behind the weld spot, it acts as a heat sink.

By all means fill between the spot welds, but alternate from the farthest side of the panel to the farthest side of the panel. This will minimise the heat build up in any one area.

cheers Chuck.

[blacktop]

you may be able to fix the warping by metal filing.


the process I used when working in a sheet metal shop was just to tack every 15cm, this was with an Arc welder, I find it gives me more of a running start to fix what I'm doing wrong.

[TRAV-KE55]

I'd suggest using a mig instead of tig, the tig has to much heat involved where as the mig is a much quicker process and puts less heat into the panel, dont be afraid to hold a dolly behind the weld and hammer the weld on the other side either, this will help stretch and relax the weld pull somewhat/
Where you have a hole or gap to fill use a peice of brass behind not so much as a heat sink but you can weld over it without the weld adheiring to it, makes building weld up easy.
Trav

[JP]

for thinner filler wire, I use plain mig wire on the roll, just make sure it's not flux core

I use 0.8mm wire from memory for my thin-wall tube stuff. A perfectly ground tungsten will also help with a steady arc at the low amps you'll be using.

[ReQuieM]

Thanks for all the replies guys, keep the tips coming!

A couple of quick Qs tho, with heat sinking, how are you holding it to the sheet? I don't have any edges near by to clamp it to. Will a welding triangle hold brass? Sounds stupid but I'm not sure if its magnetic or not. Any preference on the thickness?

OH and while on the topic of welding triangles (magnets) is there a way of maintaining their power? Mine seam to have lost at least 50% of their power over the space of a few weeks work. Admittedly they do have quite a bit of metal splinters attached to them. Will removing all of the shavings 're-power' them? If so is there an easier way to remove them other then sitting down for an hour and picking them all off?

Thanks for the Wire tip JP, I've been told before but obviously forgot it as soon as I heard it! lol Is using the 1.6mm rods actually adding to the difficulty of the weld?

I only have access to a Tig atm so I'll have to persist with that for the moment and I'd rather weld up the window then use a hardcore adhesive, especially now that I've started already. But thanks for the suggestions!

It sounds like I'm finally on the right path, some what, I might just have to persist and take it slowly.

[JP]

using the thinner wire is HEAPS easier than the 1.6mm rod in my experience

[ReQuieM]

Awesome. Off to the welding shop on tuesday then!

[timbosaurus]

I actually find oxy the best to use for panel work.

Yes, it warps the panel, but that can be fixed with a hammer (slapper) and dolly after. The up side is that the weld is actually the same material as the sheet metal. With MIG the weld is a lot harder and more brittle and MUCH harder to metal-finish.

Having said that, if I'm just working on some old danga... there is no harm in MIGing to save many hours of finishing Just work in 10mm stiches, and keep a wet rag around it to stop the heat from spreading too far.

[ReQuieM]

Really? I got warned off the oxy when I was first thinking about it. Shouldn't Tig beads be the same as oxy tho? I used to use Tig rods for ali Oxy welding. The wet rag is a handy trick to, thanks!

Any chance you elaborate on you methods of removing warping? I have a few books on the subject but I've only ever 'hammer formed' smaller objects, the whole car is a little intimidating. By my reckoning 99% of the warping has shrunk the metal and pulled it out of shape, whats the best method to stretch it back out? Will I need to hold a sand bag on the other side as I hammer and slap it? OH and were can I get a good slapper? or did you make your own?

Cheers!

[takai]

OH and were can I get a good slapper? or did you make your own?

Cheers!

I hear you can get a good one in Frankston.

When i did the sunroof in the car i was advised to create a lap for the metal to sit in, its called Joddling the panel.
You use a tool like this:


In the end i simply tacked a few strips of 25x1mm bar to the underside, and then tacked the panel to them, and skimcoated with sikaflex on the underside and bog on the top.

[Alex]

Really? I got warned off the oxy when I was first thinking about it. Shouldn't Tig beads be the same as oxy tho? I used to use Tig rods for ali Oxy welding. The wet rag is a handy trick to, thanks!

Any chance you elaborate on you methods of removing warping? I have a few books on the subject but I've only ever 'hammer formed' smaller objects, the whole car is a little intimidating. By my reckoning 99% of the warping has shrunk the metal and pulled it out of shape, whats the best method to stretch it back out? Will I need to hold a sand bag on the other side as I hammer and slap it? OH and were can I get a good slapper? or did you make your own?

Cheers!

To stretch the metal use a flipper (have'nt heard of it being called a slapper) hold a metal "dolly" behind the area you want to stretch then flipper lightly, try not to over stretch otherwise you'll have to "heat shrink" with an oxy and then maybe stretch again if you shrink too much.......so take your time.

I made my own flipper at trade school and still have it now, 14" bastard file, heat up the middle area with an oxy then put 2x 45degree bends to form a handle then grind the handle area flat so that you're not filing your skin off when you use it.