I'm currently restoring a 1971 VW Beetle 1300. I can handle the mechanical work no problem at all, but I'm having trouble with the welding.
I have both an electric arc welder, and a Mig welder, but have not been getting great results with either. Mainly I keep blowing holes through the existing metal (its thin!) when trying to weld patches in. I've tried turning down the power and so on, but after much practising and cursing I'm still not getting very good results.
With the arc welder I'm using 1.6mm rods with the power turned down to about the lowest the machine will go to.
With the mig I think the fact that I'm working outside causes the gas to get blown away too easily, and gasless mig wire (I'm told) is no use on old, thin metal like the Beetle.
Anyway, if anyone has any tips or links to good welding sites I'd love to hear about them.
Or if anyone lives near Kirkintilloch (Glasgow) and would like to earn a few quid giving me a few lessons I's love to hear from you too!!!
You'll not really stand much chance with 1.6 rods MMA welding on car body stuff, it's just too thin. If you're using a cheap 'buzz-box' welder then you're really fighting an uphill battle - you're in with a better chance with an inverter welder. But really you have TIG, MIG or gas at your disposal and that's your lot.
I don't have enough experience with mig to comment meaningfully because I'm still on oxy-acet, but the gas you use is important I believe as is getting the metal totally clean of rust first.
There is at least one very good welding news group, last time I made an enquiry I had more good advice than you could shake a stick at. sci.eng.joining.welding I think was the one.
Forget the arc... even Noah couldn't MMA weld very thin steel.
possibly, but you can always turn the gas flow up a bit, or try to shield yourself from the wind, and the main ill effect is a dirty-looking, weak weld.
Check your technique by running a bead on a piece of bright, new steel of the same thickness that you're trying to weld on the car - say 20g, or 1mm. If that works OK, but you struggle with the car, it's probably because you haven't got it clean enough. It's the big shock to anyone converting to MIG from oxy-acetylene, where you can make a passable job welding through paint and rust. With MIG, it really does have to be bright and shiny to keep the weld going smoothly. Make sure you've got a really good earth connection - if necessary clean up somewhere with a grinder for your earth clamp.
Learn to recognise the sizzle of MIG welding working properly - if it's all spit and pop you're doing something wrong. Use an auto-darkening helmet and a good pair of leather gauntlets
Then practice again, and again. There's a world of difference between being able to MIG weld, say, a trailer chassis from new 3mm steel angle in a textbook welding position and patching an old car where you simply cannot achieve the "correct" torch angles or directions.
================================== As already advised, forget the arc welder.
You say that the metal is thin so I would suggest that you may be trying to make your repair patches too small. When you cut out rusted areas cut back to good solid metal which usually means cutting much more than first appearances suggest. The metal of a Beetle of the age you're working on should be thick enough to be easily welded with either Mig or gas.
In non critical areas (bonnet, wings etc.) you can use your Mig welder as a spot welder. Drill holes (about 3/8") around the edge of your patches, clamp in place and create a weld pool through the holes until you form a little 'mushroom' weld.
Thanks Kevin, That's great advice. I'll spend some more time practising!
The thing you said about the trailer welding is so true, I bought the Mig thinking I'd be good at it, because at college WAY back in 1987 I was great at welding - top of the class! But it was on seriously heavy metal - like 8mm thick.
Learn to weld first. Get your MIG, a wheelbarrow full of scrap steel (thickish stuff, not 20 gauge) and practice on heavy gauge until you've got the technique spot on. Turn the dials right up, especially the feed rate, and learn the _process_ first, only worry about toning it down for thin sheet afterwards.
Also learn how the process ought to work. I'd suggest Gibson's "Practical Welding" as 10-15 quid well spent, but these days you can probably get a reasonable defintion from wikipedia. You _must_ learn what "spray transfer", "constant voltage" and similar terms mean in the MIG context. It's not much to learn, but it's important. You'll never judge what's going wrong unless you know a tiny background to _how_ it;'s supposed to work.
Also, use decent shield gas (which _will_ cost you bottle rental) rather than CO2 from the pub.
If you can find / buy one, an automatic helmet is well worth it (70ish quid these days)
Also it's a Beetle (or a Moggy Minor), either of which is easier (ie thicker) sheet steel to weld than a Ford Escrote, or (&deity; forbid) an unweldable Ford Sierra.
sci.engr.joining.welding and searching this group's archives hould be helpful too.
IME youve got to go much further than that. What looks & feels good & sound is still too thin to survive welding. ISTR a few inches further all round was needed, but am not 100% on that.
Last time I welded one up I used gasless wire, and it went very well. Joy to use actually.
One of the biggest issues with welding thin sheet is that most welders dont go down low enough to do it, and the excess heat just blows a hole. The sales pitch seems to be about big numbers, you only learn you need smaller currents later.
Arc welders are widely used in poor coutries for car work, but anyone who's used one knows their downsides. The plus point is that if you can use arc, gasless wire is much easier.
Hmm, I migged strut tops and sills on the Mk1 and one sill, foot well and quite a bit around the n/s rear cargo bay (floor, inner arch, chassis) on my 83 Sierra Estate and it all went ok?
Scrapped it at 23 yrs old with an MOT cos I had too many cars ;-(
Please don't forge posts to look as if you're quoting one of my posts, and suggesting that I recommended it. Coupled with your faked posting headers, this looks an awful lot as if you're spamming your own site.
As for the quality of the site's tutorials, then they're pretty worthless. They're notes from one amateur welder, only using DIY-grade kit, who has found one technique that works for them on one class of work and they've described what they can see.
The trouble with this is that it teaches nothing of _why_ some techniques work and some don't. There's no _understanding_ behind any of this. How can anything claiming to be a MIG tutorial fail to mention:
gas choice
transfer mode (this site seems to think there's a single continuum with a single optimum)
positional welding beyond "push" and "pull"
There's no shortage of good tutorial material out there. We don't need this one.
Two words, argon mix. I never weld without it. Also welding different thicknesses togther can be tricky - you need to weld more on the thicker new stuff and let it melt into the thinner stuff but really you should be getting rid of thin stuff and repaling it with all new. ...for a resto. For quick & nasty get you thru the MoT then it's a different matter.
Rear panels, esp. around the rear axle of a Sierra are a high-tensile steel (chosen so that Ford can make it thinner, lighter and cheaper). It's not weldable without care, and if you aren't careful, you weaken it. Naturally these thin panels are also the ones that tended to need the welding.
Use your hoof on a powerful Sierra, like a Cosworth or a V6, and you can get all sorts of problems where the rear axle wants to pull itself free from the bodyshell. Similarly for estates that are over-loaded by lumberjacks!
It's a bit like bike frames and the 753 / 853 tubing. 853 is stronger owing to a complicated factory heat-treat process, so the tubes were often made thinner. You can over-heat either and still get a joint, but of you do it to 853, you convert it back to mere 753 afterwards.
See some of his other posts. I think he actually wrote what looks like your post being quoted. No subterfuge, he's just incompetent at quoting properly.
You can MIG weld thin sheet with a huge current (if you're doing enough of it, quickly enough), you just need to be even more careful about the manual skills of controlling the weld pool. Big weld pools on thin sheet are tricky! A MIG welder is a constant voltage device, so the current just tracks the demands you make of it, it's not a control input.
What most DIY users don't realise is that the "current control" is actually the wire speed (or maybe that the wire speed is also the current control!). The amount of wire you feed has a huge effect on the current and thus the neat input. This is why when lerning, one of the first things you should do is to investigate the effects of turning wire feed right up and using spray transfer mode.
I think you have hit the nail on the head there. You can see some pictures of my beetle, and my welder at
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where there is also a picture of the power rating plate on my welder.
I took the advice above and practiced on a bucket load of scrap metal
- cut from the original wings from the same car, and got it clean of all rust and paint, down to nice clean shiny metal and just tried running beads of weld along it - again I just ended up blowing holes right through the metal - I was finding it impossible to get a bead.
I have read some books and web sites on mig welding technique, and on thicker metal I can get reasonable results, but on this body work metal I just cant.
If you left of the cheaper bit it could sound like racing spec stuff Andy ;-)
Mine only needed doing at the back (along with along the side (sill / floor pan) because of poor post-accident damage repairs. The rear glass had to be changed when some bright spark tried to cut it out (via the rubber) only to find it was direct bonded to the tailgate. The re bonded glass must have been leaking, rotting the tailgate out and filling the under floor up with water (on the ns). Ns sill / floor was solid but o/s was hit by a truck and badly repaired (again, leaking and that killed it).
Understood, this was only a SOHC 2L but sill pretty lively compared with the 1.4i Astra and 218SD Rover we have now!.
Well, I can't say it was *never* 'well loaded' .. . I tell you though, I really miss that old workhorse. L o n g flat loading area and the bay rear glass would enclose stuff that was sticking beyond the rear body line. A l o n g roof with real gutters and Thule roof bars that carried all sorts of (5m long) things. Towed all sorts of things with little effort and in 98,000 miles never let us down (I lie, a cam belt at 90K+ 500 yards from home, a seizing front caliper that got us home slowly and a broken clutch cable but I carried a spare).
A mate of mine runs his own photo copier Co and was telling me about what happens to all the older kit he pulls back off site after lease / rental etc.
All the really old clunky electro / mechanical stuff get's exported to Africa / India where they can easily repair it and keep it running.
When he offered the exporter a much later colour jobby he said 'no thanks' (as he knew it was un repairable).
Similar to a relative who has a Pug 106 going spare. It's chucking out black smoke and the repair could be expensive. If it's the lambda sensor (£100?) cat (£150?[1]), fuel injector pump (£150?) or computer (£150 exchange) ..?
How much energy / pollution would fixing it create compared with my very basic but 'dirty' 1300 Kent powered kit car which is easily / cheaply fixable?
All the best ..
T i m
[1] Would need changing as now anyway as it's 'polluted'?
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