What tig welder would I need to re create this part

[SierraV6]

As per the other replies, what you’d like to attempt is a mammoth task! Even working with 2mm steel is a lot more difficult that shaping body panels at 1mm (or less). I, like seemingly everybody else on here, am up for a challenge but sometimes you need to be realistic about what you can achieve with the skills, equipment and time at your disposal.

If tubular arms aren’t allowed, I’d think about adapting something; how far out are the road car items? Even then, it’s obviously a safety critical part so you’ll need to be sure it’s done properly.

 

[Brad93]

You’re steel gonna have to be ChromeMoly and may need a heat treatment after welding.

 

[slim_boy_fat]

It’s from a bmw z4 gt3 motorsport car, I brought the chassis a few years ago now

Can you stick up pics of the car, please? Is it still liveried? Be very interested in seeing it.

 

[stuvy]

Ask a local engineering company how much to make it

or as mentioned get the parts made to spec and make the rest out of tube

 

[NathanO]

Ok my first attempt at forming one of the curved 2mm pieces,I need to tidy the edges but a lot of hammering and two blisters later

 

[Munkul]

Oh, that's nice! I have a feeling we were all underestimating your abilities.

Are you sure those parts are just mild steel, though? Like Brad says, it's likely to be chromoly if it's a bona fide GT3 part.

 

[Shox Dr]

Oh, that's nice! I have a feeling we were all underestimating your abilities.

Are you sure those parts are just mild steel, though? Like Brad says, it's likely to be chromoly if it's a bona fide GT3 part.

I wouldn’t like to form that by hand in 4130. Would be easier to make in 2 parts.

Nice work.

 

[NathanO]

Not to sure , I’ve been looking in to it and some off-road races use mild steel rear trailing arms, but maybe not as this is tig welded.

 

[seanc]

Something tells me you may not be as new to fabricating as your first post sounded

 

[minimutly]

Pretty much all autograss (offroad) fabricated rear wishbones are mild steel, mig welded. Maybe a little heavy, but they never break, and only bend if there is a coming together.
None are as tricky as yours though. But if you make a jig from your pattern I can't see a problem.

 

[SierraV6]

Ok my first attempt at forming one of the curved 2mm pieces,I need to tidy the edges but a lot of hammering and two blisters laterView attachment 226493View attachment 226494View attachment 226495View attachment 226496View attachment 226497View attachment 226498

That’s a good start, I suspect you have more experience than you first let on.... Did you tuck shrink the edges to form the curve? If so did you have to heat it?

A couple of further questions if you don’t mind:

1. What are you using as a form? Presumably something fairly durable!

2. As good as it looks, are you confident that it will all be dimensionally accurate? I imagine you’re working to tight tolerances.

Keep us updated with your progress.

 

[NathanO]

Yes , I had a shrinker/stretcher delivered yesterday just in time try it out , I was a bit sceptical to if it would work or not as working with a Shrinker designed for smaller gauge steel,no experience forming steel at all,I made a cardboard template of the original part and thenmade a forming block out of timber faced with 2x sheets of the 2mm steel,then with the same template added 20mm or so to the edges then clamped it to the block and dressed to metal over the form , I headed the steal mildly with a blow torch but not to hot as I didn’t what to get to much heat in to it .
Im confident it will work but it’s early days, at the end of the day I know now I can form the shape which I was not sure would work with out heavy duty industrial bead rollers and shrinker/stretcher.

Im going to make the internal curve pieces next , I’ll do a step by step on the next piece, which my be a few days off as the weathers crap and I’m stuck in the house decorating .

I spoke to a guy yesterday at proformace metals in Daventry and they supply the motorsport industry,I may get a sheet of s515 and try to see if I can make it out of that which will make the part even stronger, don’t fancy trying chrome moly as you have to pre heat before tig welding and heat treat after from what I can gather.

 

[NathanO]

 

[carbon]

Pretty much all autograss (offroad) fabricated rear wishbones are mild steel, mig welded. Maybe a little heavy, but they never break, and only bend if there is a coming together.
None are as tricky as yours though. But if you make a jig from your pattern I can't see a problem.

Made some rear swing arms for an autograss mini some years ago, went from this



to this



definitely not as complicated but withstood the punishment

 

[Shox Dr]

Yes , I had a shrinker/stretcher delivered yesterday just in time try it out , I was a bit sceptical to if it would work or not as working with a Shrinker designed for smaller gauge steel,no experience forming steel at all,I made a cardboard template of the original part and thenmade a forming block out of timber faced with 2x sheets of the 2mm steel,then with the same template added 20mm or so to the edges then clamped it to the block and dressed to metal over the form , I headed the steal mildly with a blow torch but not to hot as I didn’t what to get to much heat in to it .
Im confident it will work but it’s early days, at the end of the day I know now I can form the shape which I was not sure would work with out heavy duty industrial bead rollers and shrinker/stretcher.

Im going to make the internal curve pieces next , I’ll do a step by step on the next piece, which my be a few days off as the weathers crap and I’m stuck in the house decorating .

I spoke to a guy yesterday at proformace metals in Daventry and they supply the motorsport industry,I may get a sheet of s515 and try to see if I can make it out of that which will make the part even stronger, don’t fancy trying chrome moly as you have to pre heat before tig welding and heat treat after from what I can gather.

In general 4130 does not require heat treatment if its under 1/4", nor does it require preheat

 

[NathanO]

In general 4130 does not require heat treatment if its under 1/4", nor does it require preheat

Oh ok that’s for the info

 

[NathanO]

Thanks for the info

 

[NathanO]

Made some rear swing arms for an autograss mini some years ago, went from this

View attachment 226755

to this

View attachment 226757

definitely not as complicated but withstood the punishment

They look great mate

 

[SierraV6]

Yes , I had a shrinker/stretcher delivered yesterday just in time try it out , I was a bit sceptical to if it would work or not as working with a Shrinker designed for smaller gauge steel,no experience forming steel at all,I made a cardboard template of the original part and thenmade a forming block out of timber faced with 2x sheets of the 2mm steel,then with the same template added 20mm or so to the edges then clamped it to the block and dressed to metal over the form , I headed the steal mildly with a blow torch but not to hot as I didn’t what to get to much heat in to it .
Im confident it will work but it’s early days, at the end of the day I know now I can form the shape which I was not sure would work with out heavy duty industrial bead rollers and shrinker/stretcher.

Im going to make the internal curve pieces next , I’ll do a step by step on the next piece, which my be a few days off as the weathers crap and I’m stuck in the house decorating .

I spoke to a guy yesterday at proformace metals in Daventry and they supply the motorsport industry,I may get a sheet of s515 and try to see if I can make it out of that which will make the part even stronger, don’t fancy trying chrome moly as you have to pre heat before tig welding and heat treat after from what I can gather.

I feel your pain re the decorating!

I’ve thought about making some forms that way myself but never have, for thin body steel plain timber/plywood is fine but adding steel to the faces obviously produces something longer lasting.

Again, keep us updated it’s an interesting project.

 

[stevieturbo]

It's one think copying the parts visually.....IMO the first thing you need to make is a jig based around the original arm, locating all critical points to enable you to actually make an exact copy.