exhaust manifold wall thickness

[Jonny81191]

If I was to weld up an exhaust manifold in mild steel, what wall thickness tubing would be best? I'd be supporting it at both ends, so I'm only really concerned about heat absorption and prolonging the lifespan of it.

[Dum-Dum]

from what ive seen it appears that people use standard thickness exhaust tubing.

[Rippthrough]

If you're not taking the weight off a turbo, etc, 1.6mm will be fine.
If you want it to last a bit longer I suppose you could use 2mm.

[Jonny81191]

I was thinking about 3mm, is there any reason not to use that?

[Poodle]

Should think itd start getting difficult to weld at that kind of thickness wouldnt it? Thicker it is the more energy itll carry to the turbo.

[Jonny81191]

Nah 3mm is easy enough to weld. But I'm more concerned about the lifespan tbh. Don't want it cracking

[Ruan]

3mm!

Christ, you looking to hang some serious weight off it!?!? 3.2mm is Scaffold pole you realise and I think we'd both agree Scaff is just a little over the top for an exhaust, also SERIOUSLY heavy in like 2.5"!!!

2-2.2mm max I'd say!

[Jonny81191]

See that's where I need help

I'm aware of how thick 3mm wall is, but I'm wanting this to last, hence my question. I'm also considering using thinner stuff further away from the head after the collector.

[darrenjlobb]

2mm tbh.

I wouldnt go any thinner if your welding it yourself, as can be tricky, any thicker and it gets heavy, but no harm for a home build....like if i was on a budget, and had scafold kicking about, then it would come out....just like it did when i welded ruans VNT adapter....lol.... agri spec ftw

[Rippthrough]

Nah 3mm is easy enough to weld. But I'm more concerned about the lifespan tbh. Don't want it cracking

The tube I've got for doing mine is 1.2mm

[cully]

3mm is good if your using a stick welder