MIG upgrade, TIG or Oxy acetylene

[sladey]

I've got a birthday coming up. I'm enjoying the bodywork. My welding still appears to be pants. I made a frame last year for a playstation seat and I was overall very pleased with the welds on that - they varied from messy to pretty good really, and I could point my finger at why the messy ones weren't so good. That was all welding square bar tubing which is pretty thick

Recently while working on repairing a body panel I've been welding thinner stuff. The welds look pretty horrible and blobby. When the metal got thinner I blew a bit hole through (Oh joy). When I drop down the wire speed and go to low power the wire isn't feeding well - it's barely moving. If I ramp up the wire speed then it's pretty consistent. I've got a SIP 150 hobby welder. I've done all the modifications to it recommended by the welding forums - added a steel liner, and made my own enhancement so that the wire feed rollers can pinch the wire properly and therefore avoid slippage.

I'm well aware that a bad workman always blames his tools, and I'm going to approach the welding more methodically this week-end to try and suss out where I'm going wrong. However I am aware that there are limitations to the 'hobbyist' machines and that a better class of machine might make it all a bit easier. Whichever route I take, I'm going to try and improve my welding with the current kit first.

It may be that as it's been standing a while I've got to go through the welder again and tidy everything up to make the feed work better. I'd rather not be doing that on a regular basis - I want to be able to weld whenever I'm ready - not have to restore the welder first.

So as I say, I've got a birthday coming up. I've been looking at bodywork courses. They all seem to include TIG welding as part of the course. So my question is this - should I:-

1. Sell the MIG and buy a portamig - sticking with MIG
2. Sell the MIG and take the leap into TIG - and stick with that until I get it right
3. Keep the MIG and invest in oxy-acetylene setup as well and start to learn that as well

Any thoughts gratefully received.

Oh and if you know of reasonably priced bodywork classes in the Midlands or north please let me know. I've found a good one in Cornwall (http://www.mphmotorpanels.com/Wheeling.htm) but the only ones nearer are twice the price

Cheers

Mark

[Gary71]

You know my answer will be Portamig:) It just works. First time everytime, even if you haven't used it for 9 months.

Having said that I'd like a decent TIG to supplement it!

[Bruce M]

It's been a while since I did much of this stuff but......

A good quality machine makes a big diference but the extra cost for low hours of use has to be considered.

When using a light weight "hobby" machine, I found it was important to keep the torch hose as straight as possible. I also prefered to use the teflon liners rather than the steel coiled liner as it stores a lot better. The teflon liner is supposed to be used with Aluminium wire but I found it was great with steel wire too. It might wear out quicker but with low useage, I never found this to be a problem.

I also used the thinner grade of wire to reduce blow-outs.

Make sure the electrical switch in the torch is working perfectly (flooding it with contact cleaner and working it lots to clean the contacts).

[sladey]

Thanks for those comments Bruce

[haasad]

The problem I have found with infrequently used MIG is that the wire gets corroded despite the copper coat and causes no end of feed control issues but with a good quality machine, clean dry wire and proper gas they really work well . However a nice suitcase TIG with a pedal control would be lovely . I would steer clear of gas welding... too difficult and too much hassle overall with bottles regulators safe storage etc etc

[911hillclimber]

30 years ago I arc and gased everything. Learnt to do it as an apprentice.
20 years ago the gas bottles ran empty just as i finished the shell on my beat-up 911
5 years ago bought a thin steel welding MIG and at first struggled but found the secrets so all is well and solid.
Today I would go to tig. Looks all a bit like gas welding to me, but costs are v high.

If you go TIG tell us please what you went for on here.

[sladey]

Thanks - will do - I'm leaning towards TIG as it seems good for structural stuff as well as outer bodywork stuff. I appreciate it's a new skill to learn when I haven't really learned my MIG yet but it seems to be something worth sticking to. I note that on the bodywork classes they generally give lessons in TIG - not in MIG

I'm thinking of this one
http://www.weldequip.com/inverter-fusion-tig.htm

Though it's quite a lot to spend. Would welcome any recommendations.

[sladey]

OK now I'm turning into Dave from the fast show - now I'm leaning towards upgrading the MIG

I found this answer to someone else's similar question on a welding forum:-

"More to your specific question……..MIG or TIG, and given that you are primarily addressing the restoration of body sheet metal on what to me is a relatively late model vehicle, I agree with the others who say “go first with the MIG”.

On working with jobs like floor-sections which will be covered eventually with carpet, what does it matter if the metal is uneven? In this application, any of the three welding processes would do fine, and maybe the gas setup would be less expensive, though it requires two hands – one for the rod. Little things come into play, believe me. I have also done that kind of thing (floor sections, battery boxes, etc) with MIG and with great success. Here the TIG is sadly out of place completely (though it could be used); like gas it requires an extra hand holding the rod and the additional work space, which that operation requires. Worse still, the TIG also necessitates one having a foot (no, an assistant will not do) or a third hand being free to operate the remote pedal. Imagine all this commotion in progress, while on your back under the jack-stands! Forget it, for it just doesn’t work unless you have a three-arm freak on the payroll. TIG is wonderful for production work at the bench, while seated in a comfortable chair with the coffee cup always close at hand, and the gentle, soothing strains of , say, Brahms on the music system. It is also the preferred process for building up of new replacement panels. But TIG doesn’t lend itself to the ridicules positions we find ourselves in, during actual welding on a car or truck. Usually a MIG can get right in there - and all you need to work with - is a single hand!!!

The other, and not to be ignored issue is heat distortion. Here the MIG wins, hands down. The most useful all-around welding setup is oxy-acetylene. The nicest thing to use if you are working from a chair at your production bench is a TIG. But if you are going in for a lot of rust repair, probably with made-up panels to be welded in then start your learning curve with the MIG. Count on spending for a full-face helmet with instant-darkening lens – the greatest improvement to come along during my experience. "

[veryporky]

Re problems with corroded mig wire, Barry recommends removing it when not in use and storing in the house....

[Nige]

If you haven't really mastered MIG yet Mark I'd stick with it. It'll cover 99% of the jobs you want to undertake, you can still do the outer panels of bodywork with it.

If you want to upgrade go and visit the guys at http://www.welduk.com/ they're just down the road from you. A little bit 'run out of a shed' setup but the guys are very helpful and full of advice on what is best suited for you and your needs.

Amongst many other things, they also told me to keep the wire warm and dry as badly kept wire can cause a lot of feed problems.

[sladey]

Fair point on the wire Nige and VeryPorky

On WeldUK - I just bought my gas bottle from them

[Nige]

Fair point on the wire Nige and VeryPorky

On WeldUK - I just bought my gas bottle from them

That's where I got my midi gas bottle from too.

[Barry]

Not been on DDK for a while, but here're my thoughts for what they're worth.

I've got all three options, plus spot.

The gas never gets used on 911's other than for brazing and the occasional detail. Just too crude for most jobs.

The MIG is the real mainstay: you absolutely cannot do without a MIG welder. It can do any job on the car, including spot (plug) welding. Secret is to put as much money as you can into whatever welder you buy, although I always say it's much better to go for an elderly professional machine, than a shiny cheap new one. I'm using a Kemppi Minarc MIG 150amp, which is a tiny package (being inverter technology), was around £600 and I find very good. I've also got a very old BoraMig 180 which is very smooth at higher amps, and did me for nearly twenty years.

The strength of the MIG, other than it's versatility is that it can produce distorsion-free welds if done right. Align two parts, tack using the welder at near full power (5 out of 6, 7 out of ten or whatever). Tack one inch apart using knife blade to align if you can't get behind it. Let cool, and go back and re-tack in-between (so you now have tacks every 1/2 inch). Linish (sand) off near level. With the welder still up quite high, seam-weld between tacks, leaving plenty of space and time between them. Don't let heat build up. Once linished off, you can end up with a flat, near invisible weld.

As for the TIG: it's brilliant for fabricating more complicated sections on the bench, as you can use it for fusion welding. This is simply melting the edges together with (amost) no filler rod. Align two parts: they must fit perfectly, so overlay one over the other, scribe along, then cross-scribe at right angles so you know exactly where they fitted together. Trim and file until they match perfectly. Hold together at one end, and about 1/4in in, use the arc to heat one side then the other (a second or so on each), bring the arc to the join and tack. Move down one inch, warm one side, then the other, and tack in the centre. Repeat all the way down. Use hammer and dolly to get edges tidy, and starting at one end, run the arc all one motion all the way down the weld. You'll see a tiny 'jiggling' pool of scum floating on the weld pool. This is what you are guiding, and shows the size of the weld. If you blow through, go back later with the filler rod (or MIG) and fill in. As you get better, have filler rod to hand to fill in as you go. Tap up the work once cooled.

The TIG is brilliant for fabricating and for welding on sections of outer panels (the kidney bowl area of the rear wing is a good example), where you can get to the other side with hammer / dolly. It is not practical for attaching sills, kidney bowls, wing closers etc to the body itself. It leaves a fairly soft weld, that takes well to being tapped up, unlike the MIG that leaves very hard welds that don't take well to excessive hammer / dollying. If you try to use the TIG where you can't get behind the weld, you'll just end up with a load distortion that you can't beat back out. On the other hand, if you can get behind it, you can acheive a near-invisible, well tapped up join that is a real joy, all with no grinding.

I would say that % wise, I use the MIG for 95%, and the TIG for 5%. I love my TIG(s), but the difference is that if the MIG's weren't here, I'd be in trouble almost straight away. If the TIGs weren't, it would be a shame, but wouldn't be a huge issue.

So, I'd first make sure I had a really (really, really) smooth MIG that just did weld, after weld, after weld, just as you expected (not one that suddenly does a wobble just as you've welded in the most inaccessable, hard to grind area).

After that, if I was doing just steel (or at least, not ally), I'd go for an old, but nice quality DC only TIG welder ). They are no money, as everyone wants AC/DC TIGs to do ally work. If I liked it, used it, and was able to feed wire as I welded (one of the key skills), then I'd finally go for a AC/DC (Can't remember what make mine is) just because it's a nice thing to have.

I can also really recommend the Spotmatic hand spot-welders. I have the more powerful 2mm+2mm (rather than the 1mm+1mm). These are very good indeed, and currently go for around £250 on E-bay (going up though). They are very powerful, as they're not having to create a huge magnetic field along the whole length of welding cables. Effectively, because the transformer is right at the weld site, they can pack a big punch very efficiently. Therefore they produce a spot-weld that easily passes strength tests. O.K. you can't do a huge run of welds one after the other, but that's rarely a problem in this field.

So, if I was DIY'ing, I'd get a lovely (poss second hand), pro-quality MIG (150-180 amp), a DC only TIG (around 150 amp, if that), and with any change, get a Spotmatic spot welder. You could do the whole lot for £1000, it would all hold it's value and should be a pleasure to use.

HTH, and sorry of I've gone on for a bit .... .

[Nige]

So, I'd first make sure I had a really (really, really) smooth MIG that just did weld, after weld, after weld just as you expected (not one that suddenly does a wobble just as you've welded in the most inaccessable, hard to grind area.

Amen to that and something I need to resolve as my shiny new welder doesn't achieve this Unfortunately or rather fortunately it's broken so needs replacing.

[Barry]

Oh yes, on the whole, if MIG welder has a detachable torch lead (Euro fitting), and a metal wire-feed mech, it's pro. If the lead is non-detachable, and the wire-feed is all-plastic, it's probably more DIY.

Having said that, my Kemppi breaks both these rules, but it is in a tiny, portable inverter package, so I guess that's why. The Bora-MIG is very much all metal, pro-torch and massive componants, but very old school. Still brillant though.

One tip, if you have a MIG that is being demo'd, make sure you try it at the settings you are going to use: most can cope quite well at the higher end as they smooth out. It's much less crictical on the wire feed and rectification. As the power is dropped though, it becomes much harder for welder to operate reliably and smoothly. Therefore try it turned right down low, and lots of stop-start welds. Again, most welders will settle down on a long weld, but you rarely do those on thin bodywork.