First attempt car body work

[Tobymizzi]

as someone who has welded things that should not have been welded with all the structural integrity of a doyley.
Power is your friend,
most welders will start at around 20-30 amps, if you are doing a nice long run on clean 0.8/1mm thats fine.
on old body work that can be as thin as 0.4mm where it has been drawn through the stamping process, you want to to get the melt pool to form as quickly as possible, will normally use around 60-80 amps with 0.8mm wire, and a copper backer if you can, a bit of old 22mm water piper flattened works OK.
When you get used to it, you can work along a panel quite quickly, you get a nice rhythm going, you do the next weld while there is still a tiny bit of heat left in the last weld. and when you weld, try and put the arc more onto the new material, around 60/40
as others have said, practise is your friend.

Yes I was watching a YouTube video and someone demonstrated it with more power and it makes sense!

Looking forward to trying it out.

 

[charlysays]

Which leads on to this pic below robbed from the dune buggy thread
View attachment 439749
Why do you get rust like this mainly on mig weld runs like this Suzuki chassis?
Personally I wouldn't include extra water / condensation traps for the sake of a little fitting even if some find the extra filler that over-plating requires beneficial.

I think it's something to do with the heat affected zone. The heat from welding causes metallurgic changes in the structure and composition of the steel which make it more prone to corrosion, effectively creating a galvanic mismatch with the surrounding metal which causes the weld to rust much sooner than the surrounding metal. That's my understanding of it anyway!

 

[Dieselman 63]

I welded arches on an Impreza or what ever they were called , they certainly were not 1.5 , closer to 0.8 Id say , very very thin and the rust was not helping.

you wont be running beads on one ,,, so dont beat yourself up over that.

Having also welded Subaru steel its horribly thin and so so easy to burn through.

 

[Dell]

All my working life I was a coach builder, I worked for a company that made replacement bodies for R/R & Bentley until later in life running a bodyshop for a coach company, I won’t go into the reason for the move apart from saying health reasons, anyway although most of what I did was gas welding aluminium sheet panels I also used steel again mostly gas weld and I was always told when learning many years ago to turn the very edge of the remaining edges of the cut out and the replacement panel very slightly towards the side being welded, there were two reasons for this the turned edges would cut down on distortion and because you are weld ing the two very small turned edges will give you a better weld , of course that Wes using gas but I can’t see any reason why it wouldn’t work with mig as well , worth a try I would have thought.
Just my two pennies worth.
Dell

 

[tom2207]

All my working life I was a coach builder, I worked for a company that made replacement bodies for R/R & Bentley until later in life running a bodyshop for a coach company, I won’t go into the reason for the move apart from saying health reasons, anyway although most of what I did was gas welding aluminium sheet panels I also used steel again mostly gas weld and I was always told when learning many years ago to turn the very edge of the remaining edges of the cut out and the replacement panel very slightly towards the side being welded, there were two reasons for this the turned edges would cut down on distortion and because you are weld ing the two very small turned edges will give you a better weld , of course that Wes using gas but I can’t see any reason why it wouldn’t work with mig as well , worth a try I would have thought.
Just my two pennies worth.
Dell

Now that is something I have to try ,,, I like the theory .

 

[Memmeddu]

My only bodywork experience right now is repairing some cracks on a Mercedes Vito, don't know what thickness it is...
But I've used Flux core and the results are pretty good, vertical downhill ran both tacks and beads no problem, and current wasn't enough to blow through or warp the metal .

 

[MollyNomad]

Hi everyone.

Recently bought a classic Subaru Impreza wagon with some rusty wheel arches.

Thought id have a go welding it myself as it's something I've wanted to learn for a while.
I had a bit of practise on a sheet of metal and then decided to go for the real thing.

I'm fairly happy with how it has turned out but wouldn't mind some better informed opinions!!!
Would love some advice on what I could do to make the beads more consistent.

View attachment 439595

Not sure if I’m allowed to share this video but gonna do it anyway..

When welding car bodywork you have to remember that most of the metal used in modern cars is quite thin. Because of that you cannot ‘run a bead’ in most cases(especially on flat areas as this will cause warping but also more that likely ‘blow holes’) As these are issues that commonly occur welding techniques need to be adjusted. This video shows the best way to weld car panels using a MIG machine. The presenter also builds chassis frames and does heavier projects so may be of interest to others on here for which there are other videos