TIG or MIG for car chassis welding?

  1. Chazaxl New Member

    Posts: 6
    UK
    So, my wife's car failed the MOT due to some corrosion. I looked at it - dissapointed, doesnt look that bad.

    I used to do some ARC welding many moons ago when I did my apprenticeship as an Electrician in South Africa. Wondering if its worth getting something and trying to fix the chassis bits instead of paying someone else or scrapping the car?

    I suspect I need MIG for the chassis bits - using 22 guage (0.75mm) sheetmetal?
  2. keith19 Forum Supporter

    Hi Chazaxl, welcome to the forum:waving:

    Are you sure the chassis is 22g/0.75 mm? If that's the chassis thickness, what are the panels like? Seriously, we might expect the chassis to be around 1 - 1.2 mm, if it's not something a bit special.

    TIG is better on thin metal, but an endless and almost impossible job working under a car, even if you're skilled in its use. So it has to be MIG really for DIY car work, and you need to be fairly well practiced before working on a chassis.

    Working under a vehicle is a whole lot different to welding on a bench, and takes quite a lot of getting used to, even with a MIG. If you intend using a MIG, you will need hours of practice on the bench or floor to start with, then you have to start learning positional welding, which is what you'll be doing under the car. We've been there and done it, and you can too, but it does take time and quite lot of practice, and a decent welding machine.

    You have to weigh up costs, too. To get set up with a new decent hobby MIG and all accessories will cost around £300 - £400; a bit less if you stumble on a good s/h one, but that takes more time to find.

    If you can have the car off the road some time, so you have time to look around for a good welding machine, get it and the gas and all the accessories like helmet, gloves, protective jacket, clamps, etc, then spend some time doing regular practice, you will be able to do the job. But if you need to get the car through in a hurry, pay a professional to do it this time, and learn welding for next time.
  3. Chazaxl New Member

    Posts: 6
    UK
    Hi, found the 0.75mm from other sites as to recommended sizes - not actually measured.

    I think what you are saying is very wise - I am in a rush of sorts etc, think me trying to get it fixed is a bit optimistic and while Id like to buy more tools and justify the spend - just not worth it here I suspect.

    Thanks for the feedback.
  4. Chazaxl New Member

    Posts: 6
    UK
    In terms of the chassis, not the chassis itself (FWD cars are not like 'old' cars) but its the sheetmetal around one of the lifting points and also the 2 two area are where the front suspension bits fit onto the 'chassis' behind the front wheels.

    Difficult to tell - this photo is taken from the side of the wheel (you can see the CV joint and one of the motor pulleys.

    [​IMG]
  5. keith19 Forum Supporter

    See what you mean. It doesn't look good. A lot of pricing for these sort of jobs depends on how much has to be dismantled before you can actually cut out rusty metal to good parent metal, and then weld new metal in. Then whatever was dismantled has to go back.
    If you are a reasonable DIY mechanic, or have a mate who is, and have the necessary kit, you can sometimes strip out and/or lower the mechanical parts, then let a mobile welder cut out the old metal and weld new in. Then you can put back the mechanical assembly. This can save quite a bit of money. But make sure you can rely on your mobile welder first; get him to look at the job and give a quote for welding if you are going to strip it out and put it back.
  6. FranV8 Member

    Posts: 915
    Cambs, UK
    What's the car? Looks like some dismantling will be needed to get the access for welding.

    I'd say MIG, despite having just got into TIG, the metal needs to be really clean with TIG, whereas there's more latitude with MIG. If you can afford to have the car off the road for a few weeks then have a go, you'll need that time for practice and amassing the right tools and materials, else find someone who does it regularly. Be warned though, the majority of the time the obvious rust is just the tip of the iceberg. (sorry to be a bit negative there)
  7. Chazaxl New Member

    Posts: 6
    UK
    Its a 99 Alfa Romeo 156 2.5 V6. At this stage, looks like I might try and break the car but am cash strapped to replace it. Argh.
  8. Chazaxl New Member

    Posts: 6
    UK
    Some pics of the car here:-

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
  9. keith19 Forum Supporter

    Very nice motor. I like Alfas; it's a darned pity they rust...
  10. Chazaxl New Member

    Posts: 6
    UK
    Yep. Seems from a 156 forum that Im on, the chassis on this and the 2000 model was not galvanised and I am being advised that its possibly not worth repairing.
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