Angel VW Club

Just thought I'd put this together as a little tech article as not only have I been doing MIG for a few years but I've been doing loads of projects on welding at college (not just MIG but arc and TIG too) so here's a few things I've picked up along the way;

MIG welding is very much like dating - looking good isn't as important as penetration!

Don't believe all this crap about how gasless welding wire is useless - it isn't. It just takes a bit more work. It's actually very good outside when it's windy and it's also better at getting a good weld if you're upside down a VW trying to weld in a new panel (especially crossmembers on a van!) Doing "spots" and gradually overlapping them works wonders here, plus it reduces the chances of getting welding spatter on you.

Here's an example of using gasless wire - this is me using a bottom of the range 90 amp Clarke MIG welding 3mm box section:

You'll notice it's not the neatest and there's a lot of splatter - nothing a grinder won't tidy up though. 3mm thick steel is pretty much the limits of a 90 amp MIG welder as I had the Clarke MIG on full power to do this.

Now, here's an example of using gas - here I'm using 100% Argon shielding gas (NO CARBON DIOXIDE!) welding 6mm steel plate:

This was at 130 amps using an industrial MIG welder (the few splatters are due to contamination of the metal - I didn't clean it prior to welding, naughty!) The Argon was at 10 psi (although that's would be reduced for thinner metal) I should point out that although this was a commercial welder, the only differences of this against say a home DIY 130 amp MIG are the duty cycles (this is designed to be used on a production line all day every day at 100% of it's power) and it holds huge reels of welding wire. However, the wire feed is just as temperamental as on a home unit! In fact this was worse than a home unit because if you've ever seen a reel of welding wire "let go" in a home unit and become a mess of spaghetti, you'll know how frustrating it is. Now imagine a reel of wire the size of the top reel below letting go:



In conclusion - don't use just carbon dioxide (huge pub cannisters of CO2 are a big no no!) a mix of Argon and CO2 with a bit of oxygen I'm told is easier for thinner stuff if you're just beginning although I don't have a problem using 100% Argon. I just can't believe how easy it is to produce good welds with Argon! I should also point out that the above T-join test piece was tested to destruction and it took about 6 goes with a long bar and notching the weld with a hacksaw the full length before it broke!

Also - a 130 amp MIG is pretty much all you'll ever need to weld your car up! If anything concentrate on buying a welder that can go the lowest (say 30 amps or there abouts). I would even say a if the 90 amp MIG in the range you're looking at has lower settings than the 130 amp MIG , go for the 90 amp (unless of course you're planning to weld up a lot of 3mm things.)

Well, that's it for now folks. Coming next when I have a spare 5 mins is a bit more on MIG (in particular positioning the gun) as well as other welding types like arc and TIG.

Arc welders

I thought this would be useful as no doubt you'll have seen a very cheap Arc welder in somewhere like Aldi or Netto for something like £40 and you'll be thinking "Hmm..... wonder if I could do that?"

If you've never done Arc welding before and have only done MIG, your first attempt will be absolute shite! The best way of learning Arc welding it to watch someone experienced with Arc welding and get them to really show you how it's done. I speak from experience here as I was used to MIG and spent about an hour trying to arc weld and simply couldn't. The Haynes welding manual is no use whatsoever as it's very difficult to describe. It's all to do with constantly moving the rod closer to the weld whilst moving the whole weld forward which is a pain in the arse to learn but once you've got it, you'll be amazed at how neat and strong the welds are!

Here's an example of 6mm steel T-joined with Arc welding:

In my opinion, I think this looks much nicer than the MIG weld above. Arc welding is very different to MIG in that good appearance is almost always a good indication to the quality of the weld. Another thing is you will have to chip off the "slag" to reveal the weld. The slag protects the metal as it cools but it's very satisfying to chip it off to reveal shiney beautiful welds. Plus it also means you can shout "Shut it, you slaaaag!" to your heart's content.

Trouble is, Arc welding isn't really suitable for most car repairs due to the amount of heat generated and that welds like the above are more suited to thicker metals.
So why have I told you all this and why should you bother with that cheap Aldi Arc welder?
Simple.... SPOT WELDING!!!
Normally when spot welding two pieces of metal together using MIG, you have to do a "plug weld" and drill a hole through the top layer of metal in order to weld the two together.
With an Arc welder, all you need is a 2.5mm rod stamped "6013", set the welder to about 60 amps and ZZZAAAP! 1 second later you have a perfect spot weld!
EDIT - use 30-45 amps on a budget machine - this was a very expensive "inverter" type machine using DC but I've since discovered budget machines are all AC and require less power.
Here's a spot weld on two 0.7mm pieces of steel (the thinnest I could find):

The black scorch mark line is where I started the Arc - with practice you won't need to do this. Notice this works on rusty metal too!

And the underside:


And this is me trying to pull the weld apart - I couldn't!


I'd recommend practicing a few times on some scrap steel to get the hang of this. Also, you've got the advantage over spot welders as you can reach areas that normal spot welder "clamps" won't be able to reach.
If you can find a spot welder this cheap, I'll shave my beard off and eat it!

EDIT - it's worth changing the cheapo clamp arc welding torch that comes with budget machines with a higher quality "twist type" torch - these are only about £6:

Tig welding. One word: EXPENSIVE!!!

There's two main types of TIG welder, the "scratch start" type which involves you having to scratch the surface and then lift the tip back off to start the arc, or the high frequency start which as the name suggests sends a high frequency between the tip and the work piece which allows the arc to jump enough to start welding. As you've probably guessed, the high frequency ones are the best, easiest to use and of course most expensive! You're talking around 2 grand for a decent HF set-up. Of course there's Ebay etc. Make sure you get a 240 volt system as a lot of them are designed to run on three phase 415 volts.

The TIG torch itself has a non-consumable tungsten electrode. When just starting out, you'll probably spend more time sharpening this electrode than welding as it needs to be sharp and it's very easy to put a ball of weld on the end (this makes the scratch start type even worse!)
Welds are usually achieved by either just melting the metals together or by use of a filler wire - this is usually dictated by how good the joining metals fit together in the first place. Shielding gasses are also used, usually 100% argon or a mixture of argon and helium.

The welding process itself involves getting very comfortable - seriously! If you're not in a comfortable position, you won't be able to produce good welds as it's a very fiddley job which involves lots of precise hand movement, not just with the torch but the filler wire.
I've been having serious problems getting comfortable and producing good welds because I'm not a small chap and the welding booths at college aren't the biggest.

Here's some of my recent practice welds - I'd been doing lap joints on 3mm thick steel:


You'll notice that welds 1, 3 and 4 are really crap. Weld 2 is really good however (apart from the dodgy start!). What did I do differently? Kneel on the floor and rest my wrist on the bench using a welding glove as padding! This does illustrate that TIG welding is completely impractical for most car welding as a lot of work involves welding in awlkward areas. However, something like a roll cage or exhaust or anything else that can be removed from the car and welded up is good.

Like I say though, it's EXPENSIVE! Even the filler wire isn't cheap, nor is the gas. Going to be a long time before I can afford my own TIG set-up.