MIG or TIG?

[margriff]

I've chopped the bottom skins off the back doors of my saloon and bolted the new skins in place ready to be welded. I can't do it myself.

Do I get them MIG welded or TIG.???

I have been told TIG is a much neater job and will be a little more forgiving to the thin sheet metal of a car door and that MIG welding can cause buckling?

Can it be MIG or do I defo' need TIG? But a TIG wlder is proving hard to find. I'm in the Oldham area.

Any help?

[bmcecosse]

TIG is lovely to use - but rather expensive for the 'home mechanic'. With a bit of practice you will do a good enough job with MIG - to then grind it back and skim over with filler.. Actually - gas welding or even brazing may be the best option for you. Or just take it to a panel beater and let them use their own judgement......

[margriff]

Thanks BMC.

[IaininTenbury]

Yuo can get DC tig sets pretty cheaply these days (You only need a DC output for welding steel - its the AC/DC selders which will do aluminium as well which are very expensive). Yes Tig is very nice and probably best as you can weld with very little heat spread which equals very little distortion. The technique is more like gas welding as you feed in the filelr rod with one hand whilst controlling the torch with the other. Ok if you've cone gas welding or brazing before, if not MIG is much easier for a beginner to pickup and its pretty versatile - just a little more sanding (grinding) down of the welds after but with the right sheilding gas and settings on clean metal you can get very neat looking welds.
I wouldn't reccomend gas for repairing a door skin unless you are very expert, as gas welding puts a lot of heat into a panel and on somethign pretty flat like a door the distortion could be considerable. Brazing needs less heat but its still a gas flame onto a door skin so similar risk. Also not suitable for anything structural, ie: MOT checkable but ok for doors...

[chickenjohn]

Mig puddle (plug) welding is the way to join the new outer skins to the frame with minimum distortion (and hence minimal filler needed). I wouldn't use hotter methods such as Gas or Tig on an enclosed visible box section such as a lower door as it will be difficult to get inside the lower section of the door to dress out any distortion. But yes, my favourite form of welding is Oxy acetylene gas, but not practical on a lower door repair.

[margriff]

Took the doors to a mech' round the corner, literally, round the corner. It took him 2 hours and he did a crackin job. £60 for both doors. Finished it all off nice and neat and did the grinding on the weld 'snots', saved me a job. Being filled and smoothed today. Spray painted tomorrow. Sorted.
Thanks for all your thoughts on this subject.
p.s learnt how to braze this morning. Working on this car is opening me up to learning a lot which I hoped it would.

[bmcecosse]

Aye - but as before - brazing is not good enough for anything 'structural'....

[IaininTenbury]

I did once see a true master of the craft gas weld a butted repair section in the bottom of an Austin Seven door skin (flatter than a Minor). He welded a bit, then planished out the distortion, then welded a bit more etc. The result was a virtually invisible join when viewed from either side! Awesome, but very much not for beginners. He'd been welding and panel making for over 40 years. I wouldn't have dreamt of attempting it like that and would have probably gone for the easiest method and plug welded it with mig as chickenjohn suggested. (If there was access to the back of the panel, not that you get much on a Minor door I would have been reaching for the spot welder as the most distortion free method but its a happy occaision when you've got the rght lenght tips and access to both sides....).

[chickenjohn]

Ian, yes, I too would prefer oxy acet welding and planish with hammer and dolly but only if the entire skin is off the door frame to allow access.