I am about to embark on my MGB restoration and got a brilliant DVD for Christmas that was four hours long detailing a restoration of a car like mine. One thing that they used was a spot welder.
I have a gas Mig and an arc welder and thought that the spot welder looked very handy and easier than drilling holes for plug/puddle welds. Is this the case or would I be wasting money on it? I also have seen spot welding 'attachments' for arc welders. Are these any good or a waste of money?
Thanks as always for any information, hints, tips etc : o )
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A proper spot welder is a handy and neat tool but can only be used flat seams for joining two panels together. I would say that as a DIY tool it would be a waste of money, unless you either have money to burn or a large amount of flat seams to join. You can achieve the same thing with a conventional mig welder, but it takes a lot longer and will never be quite as neat.
It is like everything though, having all of the proper/special tools to do a job (as seen in that video) is very desirable, but unrealistic in the real world. Exactly how much restoration does this MGB need?
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I used to have a 'proper' portable spot welder (quite a heavy brute actually). It had about a dozen different arm attachments to reach various awkward places. TBH I never got on that well with it. The metal has to be spotlessly clean and the required clamping force for a good weld is high, so it was quite physically tiring to use once you were holding it in the right place and squeezing the levers together.
I also once tried an attachement - kind of a 'tube' with a couple of electrodes at the end that press against the metal and a movable centre electrode that you draw away from the work to create an arc. Didn't think it was much good. Overall I reckon a plug weld is probably the best way to go on a one-off project - they are pretty much foolproof.
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Thanks for the replies!
The car will need new sills, jacking points plus a few body panels.
I think I'll go down the route of plug welds. As it is a hobby I dont need to rush it so if it takes a bit longer it wont be a problem
Cheers
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I've always got on well with plug welding, stitch welding or seam welding on old cars. If you're doing plug welds get yourself a hand held punch (hold it like a pliers) to make things quicker.
You'll probably find it easier with 0.6mm wire instead of 0.8mm which can be a bit bulky going through the holes.
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this is the attachment I bought and have had success using it.
tinyurl.com/37bvbu
The best tip I can offer (apart from lots of practise first) is to get a proper auto darkening welding helmet, so much easier than a hand held one (where space allows).
Edited by normd2 on 03/01/2008 at 10:37
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Thats very interesting. For that amount of money it must be worth a go.
I did have an auto darkening welding helmet but the electronic bit died. I need to get to machine mart and try and get a replacement module as I agree, a hand held shield makes the job twice as difficult and I have found a mig 'torch' much easier to handle with two hands.
Thanks for the info!
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I don't have an auto darkening helmet, just one that fits on my head that I can flick down by nodding a bit - much cheaper.
I always wear safety goggles inside the helmet in case the weld starts spitting back. You only get one chance with your eyes.....
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Rather than spend money on a machine like this and most likely only used once or twice, could'nt you hire it as and when you actually need it.??
Just like these big tile cutters when your wife wants a new bathroom scene, as I found it was cheaper to hire than buy. As hopefully that will keep her happy for few years.
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I'm Ok on this topic as I fitted bathrooms for 20 odd years so have the full compliment of tools!!!
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Hi stuartl
I have about 200 continuous welding hours experience of mig and arc welding but only a few hours of spot welding. In my experience once you get the mig set up (shouldn't take too long if all your materials are the same thickness) a plug only takes a few seconds to fill and a minute or so to grind down and smooth off. A spot welds take a fair while to prep in comparison. So as far as I see it unless you have hundreds to do it doesn't seem worth the expense. Unless of course you are like me and love all gadgets and toys and this is just an excuse to get a new toy. As for helmets I have an auto darkening helmet and I would never go without one now.
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Another problem with spot welders is the number of different arms that you'll need. Buying the machine itself is only the beginning.
A packet of those "reverse angle" spot-weld busting drills are very handy for cutting the 8mm holes through only one skin to do a really nice plug weld.
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Want to add my support to the 'plug weld' camp. It's years since I've done any welding, but I always found plug welding with a MIG (and also with oxy-acetylene) a perfectly acceptable welding method, especially for fitting panels. Sure, a proper spot welding machine would have been nice, but I couldn't have justified the cost.
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We have had a few things from Frost Auto, albeit a good few years ago now. A good, reliable company. I used to love reading their catalogue, but we seem to have dropped off the mailing list now.
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Mmm, all food for thought!
I wouldnt mind a go on a spot welder just to see what its like though I take on board the amount of prep needed for a spot weld over a plug weld.
Once I get going I will also be asking about things such as weld through primer, waxoyl etc as I know close to nothing about this.
Also as a general wedling question I have always wondered how you can use a welder, oxy torch, angle grinder etc on a car when it has a fuel tank in close proximity!
I intend to remove my MGB's fuel tank as I am rather worried I might end up in orbit while grinding/welding etc.
I guess I am right to be cautious but how do, say, mobile welders get on when they are welding cars up as a car requiring, say a new sill would never have its tank removed.
I have a Frost Auto book which looks great but I have an Axminster tools catalogue which is SO good! There are tools in there that make my mouth water : o )
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>>Also as a general wedling question I have always wondered how you can use a
>>welder, oxy torch, angle grinder etc on a car when it has a fuel tank in close
>>proximity!
Basically as long as it isn't leaking then it is safe to work near or next to it. Is it just as easy to set fire to other things on cars as much as the fuel tank. Things like the interior, sound deadening and the wiring are just as easy to set alight although the consequences may not be quite as dire.
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