Arc welding in the real world

[3Rs]

IM not one for boasting but it has been known that a welder can weld sweety mice. But then your talking about a very experienced welder indeed.

Yes George use the Mig (the Squart) It will make life whole lot easer, Keep your tack close to geather. In fact "TIGHT" this will reduice distortion to the patch and parent metal. If you still feel uncomfortable with what your welding, I would then be looking at your local Tech/college They will give you sound practice and practical advice.

 

[weldequip]

weldequip - my MIG welder is a Sealey Supermig 150. I was told the wire feed doesn't work but I haven't yet checked it out. I noticed that the fuse on the PCB has blown and I know that the motor works. I must set aside some time to try and get it working.

Could just be by replacing that fuse it's A1...think they are around 1-1.5amp
They sometimes blow from no apparent reason, with no fault in the machine.
weldequip

 

[GeorgeB]

scarecrow - believe it or not the first and only time I've ever seen a MIG welder in use was at last month's weld off. Aero's Portamig looked superb and so were the MIG welds which Malcolm produced to join two thin sheets. I then had a go and must agree, it seemed very straightforward. That's an expensive piece of kit though and so is the cost of Argon light gas, I believe.

migwig - thank you for the book recommendation. I'll try and get a copy via the library.

3RS - I'm sure you're right about tacks and the avoidance of too much heat. That's what I'm doing with the arc welder, effectively. If all the tack welds are close together, does that count as a continuous seam for MOT purposes, or is it still essential to overlay a continuous bead?

weldequip - I'm hoping it will work if I just replace the fuse but it almost sounds too good to be true. The seller must have given up on it for some reason. I checked that it produced a high energy 'spark' when the wire touched the work, so I assumed, and still hope that side of things is fine. But then some people on here have reported issues with insufficient power, so now I'm less sure. There's only one way to find out, I know.

 

[Wozzaaah]

George, it might have been the case that it packed up and the owner assumed it was a costly failure so decided not to bother even looking at it. If it is just the fuse then you're laughing, if not then it's fairly likely to be something else pretty simple for someone in the know to fix.
I'd think it was well worth spending a few quid on it, it will probably be quite a decent little machine once it's sorted.

 

[3Rs]

George it must be a fully welded,

When you have the job tacked down have your tacks numbered of say 1 to 10
weld No.1,5 & 10 then Numbers 2,4,8. followed by 3,6,9 this is just one method out of thousands of spreading the heat.

Just out of interested what sizes of rods are you using?

 

[GeorgeB]

George it must be a fully welded. When you have the job tacked down have your tacks numbered of say 1 to 10 weld No.1,5 & 10 then Numbers 2,4,8. followed by 3,6,9 this is just one method out of thousands of spreading the heat. Just out of interested what sizes of rods are you using?

3RS - Just to be sure, what's 'fully welded' exactly for MOT purposes? If I have dozens of tacks so the join is flooded with tacks, is that good enough? Or does it have to be a continuous bead, not that anyone will know once it's ground back and a bit of filler applied. Your 'numbering' system is what I was doing, more or less. I'm using Powercraft (Aldi) 6013 1.6mm rods, which others saw at last month's weld-off. I like them and hope another batch come up soon at Aldi stores. For any 2nd layer of arc weld bead I use 2mm rods from a welding supplier.

Woz – you’re spot on with my thinking on the MIG welder which I bought. I hope it’s something simple but, if not, almost anything can be repaired. I’m quite prepared to fit a new speed control circuit, like from Maplin, if I need to. I’m sure it will be a good machine once I’ve got it working again. I need to get on with it.

 

[Coo]

If you are having trouble holding the piece in place, then weld a piece of scrap onto the patch top help hold it in place....

 

[3Rs]

Just join the tecks together so that it creates a full weld.

 

[kleine]

hiya, i'm a newbie to this site, which excellent by the way, and i started out welding for the same reasons as GeorgeB. for what my limited experience is worth:

I Difficulties faced include:

- pre-shaping my repair panels to fit curved bits of bodywork, like the relatively complex panel shape behind the front wheels. This seems like a pressed panel. How can you recreate part of that?

a rough guide is: what you can make with the card from a cereal packet is how you'd make it with [automotive] sheet metal. arches can problematic as you often have two or three sections converging and you may have to cobble together a complete card version, in whichever way fits best, and then proceed to copying that in metal. you may have to fabricate the repair section out of two or more pieces of metal - often, i add the lip of the arch as a separate piece as this cuts out a lot of complexity in beating by hand.
i know that repair sections are available but, i mostly scavenge whatever metal i can get (generally, the off-cuts from local engineering firms).

- then, having got something roughly the right shape, getting it aligned and ready to weld is even more difficult.

as above, with the cereal packet card; sellotape can simulate the welds .
don't forget that whatever the card will do, the metal will do. if you end up with creases or bugles in the card, the metal will behave the same. the simplest way around that is to add or remove material as need to allow for the forming of the shape. you could also examine clothing as inspiration as the same idea of forming a shape/item from separate shapes is used.

- next, on this vertical panel behind the front wheel, access is very resticted inside the wheel arch.

yep, and the smell of your singeing flesh isn't nice either . i'm naughty and just use the glass out of the mask. makes it a one-handed operation i know, but most helmets and masks are too big for some car jobs, like inner arches.
don't know if you use it yet but, get a tin of seam-sealer; it's good stuff for those areas which you won't be able to access with a grinder for finishing and provides good protection and discretion (for when the mot tester gets his hammer out).
you'll also have to consider the insides of whichever area you're working on; the rear arches being more of a hassle as they can form part of the cavity-wall of the rear passenger area and this will need protecting as per the inner arch seams on the exterior (with seam-sealer probably - there's not much except a finger that can reach into the crevice properly).

- and I'm on the verge of seeing that a MIG welder probably is the best tool for such a job. I can get by with the arc welder, but I suspect a MIG welder would be quicker.

definitely a MIG . you'll be pleased at how much easier it is - and quicker. and any upside-down work will have less drop-outs falling on you; that's what's caused my grey hairs.....that's what i'm saying, anyway.
i use a Clarke hobby gas MIG for car work, nowadays. i still have my Sureweld 1400 'baby' arc which i use for small jobs at work (on lorries and fork-lifts).

anyhow, if, after fabricating and fitting a repair section, you have any doubts as to the integrity of your repair, just do what the MOT tester does: yank it, prise it, whack it. if it holds up, it's good.

 

[GeorgeB]

hiya, i'm a newbie to this site, which excellent by the way, and i started out welding for the same reasons as GeorgeB. for what my limited experience is worth:

Kleine - welcome to the forum and many thanks for such a helpful first post.

My body repairs are coming along fine. I hope they meet MOT requirements but, even if they do, the car will probably fail on something else!

The one thing I've confirmed is that, for me at least, it's essential to have practised in advance with close to identical equipment and metal thicknesses, etc, so you know what works and what doesn't. For that reason, I decided to stick with the arc welder, rather than try to bring my MIG welder into play at short notice. My basic approach has been the same as my account on the 0.8mm sheet metal thread, i.e. lots of tacks first, followed by a cap seam. I'm sure that some of the car bodywork is a good deal thinner than 0.8mm, too.

I'm still unclear - if all the tacks and short runs join up and cover the entire joint, is that OK for the MOT, eveh if ut looks a bit untidy? Or in the structural areas, do you really have to have something that looks like a single, continuous, neat-looking welded seam?

If the MOT has a free re-test, I'm tempted to put it through with some multiple tacks in places - just to see what happens.

 

[Archie]

Do we get to see some of your results repairing your car George? It would be interesting to see how you're getting on with the arc welder.

 

[GeorgeB]

Do we get to see some of your results repairing your car George? It would be interesting to see how you're getting on with the arc welder.

Thank you for your interest. I've taken some WIP photos but am concerned about posting them here, just in case the guy who ends up doing my MOT sees them by some chance. I'm getting on quite well with the arc welder, although the MOT tester may have a different opinion, of course.

 

[Hitch]

You could post them in the private section, only registered users can see them then.

 

[rtbcomp]

......... I'm getting on quite well with the arc welder, although the MOT tester may have a different opinion, of course.

I'd be inclined to go with the tester's opinion

 

[GeorgeB]

You could post them in the private section, only registered users can see them then.

The tester might be a registered user!

 

[GeorgeB]

don't know if you use it yet but, get a tin of seam-sealer; it's good stuff for those areas which you won't be able to access with a grinder for finishing and provides good protection and discretion (for when the mot tester gets his hammer out). you'll also have to consider the insides of whichever area you're working on; the rear arches being more of a hassle as they can form part of the cavity-wall of the rear passenger area and this will need protecting as per the inner arch seams on the exterior (with seam-sealer probably - there's not much except a finger that can reach into the crevice properly).

Perhaps I should get some seam sealer. Can this be used to finish the appearance of outward facing welded joints then?

Your point about 'insides' rings bells. I used a mirror to check what can be seen behind the chassis 'rail' which the lower part of the sill fixes to. I'm welding some sill patches to that. The view from behind was no so good. It's what the tester would see, looking up from the pit. Perhaps I need to jack the car right up and weld the reverse side of some joints, too. I've become quite good at not blowing holes with the arc welder. Reverse side penetration is now more of a threat than holes.

 

[Wozzaaah]

The tester might be a registered user!

Geeorge, in all honesty, what are the likelihoods of that and even if he was, would he know your user name, associate it with you and remember your car? No, of course he wouldn't!
If you have no gaps in your welds and it is properly attached then it is deemed to be continuously welded and will satisfy the tester.

Now don't be shy, get those pics up!!

 

[GeorgeB]

Geeorge, in all honesty, what are the likelihoods of that and even if he was, would he know your user name, associate it with you and remember your car? No, of course he wouldn't!
If you have no gaps in your welds and it is properly attached then it is deemed to be continuously welded and will satisfy the tester.Now don't be shy, get those pics up!!

Perhaps I'll post a partial image tomorrow, to indicate the present standard of these welds. They're not very pretty right now, but I trust they are strong. I'm tempted to leave it there for the MOT and tidy up the welds afterwards, i.e grind the multiple tacks and pigeon dropping type deposits flat and then try to lay a reasonably stylish bead right over the whole lot. This will look better but I doubt if the welds will be any stronger than at present. The simple reason for the pigeon droppings is that I'm trying to avoid blowing holes in very thin metal. So far, it's worked. The ex-welder pensioner I mentioned before said I should just do a few tacks and leave it at that. I said the MOT demanded a full seam. He seemed surprised and said noboby he knew would attempt a seam on what I'm welding. They'd just tack it and cover it up with filler, paint or whatever.

 

[Wozzaaah]

'Filler, paint, whatever' will fail, the tester needs to satisfy himself that the repair has been carried out correctly. For all he knows there's a bit of thinners tin stuck on with silicone under that glob of filler. (Yes, I have seen that done!!)
Pigeon poo might fail too if it's insufficiently fused but as long as the tester is satisfied that it's sufficiently fused to the parent matal and there are no gaps then he should pass it.

 

[Archie]

George you could save yourself a lot of hassle by letting us cast our collective eye over a couple of your welds. Those what know would be able to tell you whether the work is likely to pass the MOT or not.