light welding

[MattP]

Can anyone shine some light on a newbie who wants to do some light welding.

What equipment I need and prices.

Any thoughts welcome.

Cheers

[Harry Bloomfield]

On 29/01/2004 MattP opined:-

If by light, you mean thinner metals, then MIG is what you should be aiming for.... Car bodies and similar. Cost £150 and up.

1.5mm and up can be welded with an arc welder, using rods. Cost £70 and up.

[Lurch]

A welder, some metal, safety gear and a good book! When you say light you mean like car bodywork type of light, i.e. thin as opposed to infrequent?

SJW A.C.S. Ltd.

[MattP]

Infrequent and light work, car work, metal hobbying etc.

[Lurch]

Then you want a MIG of 100-150A rating. Have a look for a kit, something that comes with wire, mask etc... Something like this as a starting point.

A.C.S. Ltd.

[OldScrawn]

And an auto helmet, under £100 if you shop around (e.g. toolstation.com). If it's mainly mild steel, consider a gasless: wire more expensive but mor convenient, no gas costs, also it will work out of doors

[The Natural Philosopher]

You my like to consider silver soldering and brazing. You can do that with a good propane torch.

[The Natural Philosopher]

I'd use silver solder and brazing for ehlatter, and indeed often for teh former too. Wliding is cheap in wuantity, because teh weld metal is more or less stell, but it has teh severe disadvantage that it also melts what you are trying to fix to.

Persoally I trained a little on Oxy acetylene, and can handle that. Stick welding is uselss and I haven't done enough Mig/Tig to get teh hang of it properly.

Hard Soldering is IMHO the way to go.

[Grunff]

But it's sooo much fun!

Seriously, I've done a fair bit of brazing, but for steel work I'd use MIG every time. Much more satisfying.

[Dave Plowman]

For car repairs, it's not strong enough and wouldn't pass an MOT.

[The Natural Philosopher]

Brazing is certainly good enough for most bodywork repairs and probably stronger than e.g a spot welded seam. There are corrosion issues its a chassis job. Lets face it tho, if you try and pull apart a SOFT soldered plumbing joint, the pipe will fail before the joint. OK its coper, but hard soldered or brazed steel is the same. The reason its not used industrially is because spot welding is cheaper, and arc welding is cheaper and leaves no bimetallic joints.

Brazing is not AS strong, but its sure strong enough.

>

[Dave Plowman]

Like I said, a brazed joint in a structural area replacing either a seam or spot arc weld *will* fail an MOT. Any repairs to structural areas

*must* be seam welded, unless the complete panel is replaced and the original was spot welded in which case *proper* spot welds - not plug welds - are acceptable.

It would be very sad to find the carefully brazed repairs to your pride and joy make the car unusable legally.

A makers' workshop manual will often give repair instructions for bodywork to replace the factory techniques.

[Barley Twist]

Anybody know the origin of this requirement? It has certainly pushed the cost of repairs very much higher.

And what's wrong with *properly* applied and set rivets? After all - they hold aircraft together ...

Barley Twist (Please put out the cats to reply direct)

[N. Thornton]

I expect it could pass the MOT if the inspector didnt realise what it was, but you certainly shouldnt braze a car together, its inadequate. Welding is far stronger, and easy enough. Gasless wire is very easy to use, arc welders are much cheaper to buy and run, but not so easy to use, and they leave a right mess behind. BTW 40A is plenty for car work - many welders used on cars dont go low enough, make sure you get one that goes down to 15A.

Regards, NT

[Tim S]

I can recommend Cebora MIGs for light work. Had a small (enought to weld

3-4mm metal) MIG about 8 years ago. Bloody good machine in it's bracket. Smooth and reliable wire feed.

Cheers

Tim

[The Natural Philosopher]

It may, but that doesn't mean its not strong enough for the job.

I have had my car failed for having two different makes of light bulbs in the rear lamps.

[The Natural Philosopher]

Depends on how its used. Its very common on radiator repairs for example. Its perfectly OK for bodywork and exhausts. I would personally say that a seam brazed box section is stronger than a factory spot welded one.

The only place I would be shy of using it is on thick chassis members where I do agree that welding is teh ay to go.

It is on chassis. Even I can weld a chaissis. Its not easy on thin bodywork, and a poorly welded joint is worse than a well brazed one.

[Dave Plowman]

Well, if you're replacing a piece of 'solid' steel sheet, the replacement has to be of the same strength - or stronger - than the original. And in some cases the original may be weakened further through corrosion, and you can't weld rust, although you might be able to braze over it.

If the original calculations allow riveted construction, then I'd guess you could repair it in the same way. But aircraft frames are often glued as well as riveted - not really a DIY repair technique.

[Dave Plowman]

They don't examine the bulbs - only the light output and quality. If one was not red, or noticeably dull, it would fail. The make is irrelevant.

[Andy Dingley]

Brazing is not acceptable for car repairs to MOT standards. Maybe it should be, but the simple fact is that the tester's manual forbids it (as of a few years ago).

If you've built a seam-welded rally car by gas welding every alternate inch, then flooding the remainder with braze , then this is more than a little annoying ! It's the strongest way to join a monocoque and takes an age to do well, so I was less than impressed to find an idiot tester getting all stroppy about it.

I don't know how you MOT an Aston Martin either, because I'd imagine their superleggera "birdcage" construction relies on a low-temperature braze for the tubes, rather than welding.

-- Die Gotterspammerung - Junkmail of the Gods