Rear wing repair

[Stewart Sims]

Well for the last 6 months or so I've been busy practicing my arc welding as well as trying my best to get used to welding thin steel so I can tackle some areas of my MG Midget body work myself. Of course I know the score in terms of how unsuitable MMA is for bodywork, but on thicker sections it didn't seem so bad.

I've done various bits and bobs on and off the car over this time, but I thought I'd share some pictures of the latest piece which involved welding the thinnest metal so far. Here is my attempt building up very slowly a 'seam' of weld on a section above the sill at the front of the rear:

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Obviously it needs grinding back. I'll post more pictures when this is done after I tackle another patch which I might also post up here. But on the whole I was pretty pleased with this.

I welded in short bursts using DCEN, keeping the rod close to the metal as possible. I had to weave a bit, and fill in a few pin holes once done which I showed up with a torch the other side.

Let me know what you think, even if its really bad any constructive criticism welcomed!

 

[Wozzaaah]

Sorry Stewart, there is only one thing to say about that and you may not like it......
It's terrible and just goes to show why we try our absolute best to talk anyone out of using a stick welder for bodywork.
Stick welders serve several purposes but car body repair is not one of them.

 

[cumbriasteve]

I am afraid I have the same opinion as above, the chances of any real welded strength is minimal, all you have achieved is to 'stick it' together somewhat.

None of us like being negative with comments but if it encourages you to aim for even one of the cheap mig's and a bottle of CO2 it will be worthwhile negatives, you will also end up wondering why you even contemplated arc welding on a car in the first place.

 

[Stewart Sims]

That's fair enough chaps - Originally I was going to switch to MIG (or possibly even TIG) for this kind of work. I guess I got a bit overconfident thinking I could do an OK job with an arc welder given I was getting better at welding thicker steel with it.

Having said that to me it doesn't look that much different to a lot of 'hobby-welders' MIG welds I've seen, including on this car I have which have passed previous MOTs etc. (yeah I know 'MOT standard welding' is usually pretty poor anyway). So clearly these are some poor welds I am comparing this to, or I'm just not seeing the difference.

I know enough to know this is way off a neat seam, but are there any good examples out there of the kind of thing I could aim for when I do switch? I'd like to know what 6 months down the line with practice I could hope to achieve with a MIG / TIG setup knowing that it would still be far from perfect.

Also here is the link to to the 'album', for some reason the pictures are no longer showing up on the thread here for me (though given the comments maybe thats a good thing, eh!):
http://www.mig-welding.co.uk/forum/media/albums/mg-midget.909/

 

[cumbriasteve]

If you search the forum you will see some of the members work, it ranges from average to how the hell do they get that good?

I agree you do see a lot of rubbish home made welds on cars and yes they also pass the MOT with plenty of black goo thrown on them but do you really want to be the same as them?

Mig is the way to go and with practice you will get there, you obviously are keen enough, you would not be attempting to arc weld it if you weren't

 

[WorkshopChris]

What diameter rods are you using?
Looks like most of the weld is sitting on the top sheet.
Job to tell from photos it might be a shadow but it looks like there is a gap between the two pieces. You need to get the two pieced sitting in direct contact with each other. Whatever the process especially thin MMA the fit up is key.

I used to have a few 1.6mm rods that i always kept in the on site tool box they were only about 10" long might of even been stainless but they would wels sheet lovely. If i can find one i will run one on a bit of sheet to see must be at least 15 years since run any MMA rods on sheet.

 

[Wozzaaah]

Having said that to me it doesn't look that much different to a lot of 'hobby-welders' MIG welds I've seen, including on this car I have which have passed previous MOTs etc. (yeah I know 'MOT standard welding' is usually pretty poor anyway). So clearly these are some poor welds I am comparing this to, or I'm just not seeing the difference.

To be brutally honest if someone posted that on here and said they'd done it with a mig welder we'd still be telling them it was appalling.
I think there's an element of running before walking but you're on a hiding to nothing trying to do neat work like that with a stick welder.
Keep your eyes peeled for a used mig welder, someone recently posted that they'd soon be selling two Cebora 130 Turbos, one of those would do you fine.

 

[Wozzaaah]

Whatever the process especially thin MMA a mig welder is key.

I've fixed that for you Chris.

 

[Stewart Sims]

What diameter rods are you using?
Looks like most of the weld is sitting on the top sheet.
Job to tell from photos it might be a shadow but it looks like there is a gap between the two pieces. You need to get the two pieced sitting in direct contact with each other. Whatever the process especially thin MMA the fit up is key.

I used to have a few 1.6mm rods that i always kept in the on site tool box they were only about 10" long might of even been stainless but they would wels sheet lovely. If i can find one i will run one on a bit of sheet to see must be at least 15 years since run any MMA rods on sheet.

Yes, not the best photos I know but that is a shadow. In fact there is pretty much no gap. The fit up was about as good as it could get on this as I spent a fair while getting the panels to line up given any gap would blow holes so easily. I used 1.6mm rods too. I wonder if I should have kept a slightly faster, steadier bead going, rather than weaving. I was thinking without weaving, because I had the amps so low I wouldn't get much penetration.

I probably know someone who wont mind if I call round to try / borrow a MIG and TIG machine and see how it goes. Not averse to making the investment in a reasonable quality machine if I get on with it. I know ultimately that will be the way to go.

 

[Kent]

It's just not right. A hard task for anyone with stick even those with years of Experiance need every trick in the book. It's a job for mig oxy fuel or tig ( your DC welder should support tig) that said you might buy a mig sh for about the same as the kit

 

[Wendelspanswick]

As others have said it looks poor. Only about 5% of the weld has formed a proper seam, if that weld was in a critical area it would fail an MOT as weld repairs need to be continuous unless spot welded originally.

 

[Stewart Sims]

As others have said it looks poor. Only about 5% of the weld has formed a proper seam, if that weld was in a critical area it would fail an MOT as weld repairs need to be continuous unless spot welded originally.

Are you talking about the small section on the right which has a continuous, flatter profile?

It's just not right. A hard task for anyone with stick even those with years of Experiance need every trick in the book. It's a job for mig oxy fuel or tig ( your DC welder should support tig) that said you might buy a mig sh for about the same as the kit

I actually have a TIG torch attachment somewhere, but was told 'scratch start' didn't lead to very good results either. Think it is worth getting some argon and giving it a go?

 

[Kent]

Are you talking about the small section on the right which has a continuous, flatter profile?



I actually have a TIG torch attachment somewhere, but was told 'scratch start' didn't lead to very good results either. Think it is worth getting some argon and giving it a go?

Or post were abouts you are someone might let you hook up to thier bottle for a try?

I can't say it's any harder than welding thin sheet positional with a stick plant

 

[Harry_Worth]

Hi Stewart, I've a Frogeye that I'm trying to restore (my first ever attempt at a restoration) and I struggle with my mig but 'heck'- I feel your pain - treat yourself to a Mig!!!!

 

[the snooper]

mig and stick (as is labeled) are night and day in difference especially when it comes to thin steel, I started welding cars with an arc welder when I was 16 and managed well and was able to get decent welds, but would I ever go back to it on thin steel ? no not a chance

 

[PTvor]

It's no accident that just about every garage and bodyshop has a MIG set for car bodywork. It's by far the easiest and best process for the job. Years ago, oxy-acetylene was the first choice and in the hands of an expert, it's brilliant, but it takes considerable skill and there are issues with acetylene.

Stick for car panels is in the realms of the possible but difficult and who needs the hassle, especially when you can so easily spoil panels which have taken time to make, or you've bought? Those welds look horrible and it looks from the photos as if you have warping. If it's a classic car restoration rather than coaxing a banger through its MOT by slapping patches over rust holes, you really want a nice looking job.

In your position I wouldn't mess with scratch start TIG either. Just get a halfway reasonable MIG set and argon/5%CO2 mix

 

[Stewart Sims]

I ground back the welds and it will come as no surprise there were holes and it was not very firmly attached. While doing a few other odd jobs on the car I filled in the gaps and it was easier to achieve proper seams across them given there was a lot of weld on the surface to absorb some of the heat. It's not great but is so much stronger.

I'm going to try TIG out and once I've got to grips with it enough to feel confident welding on the car give it a go on any similar panels.

The whole experience of feeling reasonably confident in a weld and then realising its rubbish makes me aware how careful you need to be. If in doubt I think grinding the weld right back to reveal the true quality of the 'seam' is a good idea.

 

[PTvor]

Other things you can do if you like a challenge, you have a lot of time on your hands and don't mind spending much of it repairing the damage done trying to do the job are; cut the lawn with nail scissors, remove wall paper with a screwdriver, scrub the patio with a nail brush.

This is much the same. It's using the wrong tool to do the job. Invest in the right tool, which is a MIG set, and just get it done.

 

[Stewart Sims]

Yeah, ultimately I will invest in a MIG set up for proper car work. I have eased my way into a lot of aspects of restoration with this car knowing it will probably forever be a work in progress. Wanted something to hone my skills on and don't mind making some mistakes.

Realised welding would be the most time consuming thing to learn and started out with arc just because it was cheap and simple. I'm still happy I've done enough to get a handle on the process and think it is a handy skill to have.

 

[the snooper]

Yeah, ultimately I will invest in a MIG set up for proper car work. I have eased my way into a lot of aspects of restoration with this car knowing it will probably forever be a work in progress. Wanted something to hone my skills on and don't mind making some mistakes.

Realised welding would be the most time consuming thing to learn and started out with arc just because it was cheap and simple. I'm still happy I've done enough to get a handle on the process and think it is a handy skill to have.

mig is much more simple to weld with, its very easy to get a stable continuous arc with lower power hence less holes and no slag to remove, what you see is all steel