Hello everyone! im new here but need help!

[Adam1991]

hi everyone, im an DIY welder so im not a welder by trade or anything lol but im always on a mission to try new projects!
well heres the story.... i bought a car that handles like a go-kart on the track but on the straights its like a snail...... so i installed a turbo to it

i dont wanna take it somewhere to get it done.... id rather learn it soooo i Fabricated a turbo exhaust manifold using 3mm thick stainless steel 304 piping and a mig welder with i think stainless steel wire.
I have cut the flange off the standard manifold which is made from mild steel. however after a while the welds between the flange and piping start to leak im getting tired of it! everymorning it sounds like a tractor

ive never TIG welded before but im okay at MIG welding.
can someone please point me in the right direction?

 

[winchman]

Are the flanges Stainless?
Did you use the correct wire?
Mig welding is a lot easier and cheaper than Tig, this takes a lot more time and practice to do

 

[Bede]

You need 309 wire for welding 304 to mild.

 

[jimmyspeed]

Have you pressure tested it? I made a similar manifold out of mild a while ago and although it looked airtight it was riddled with holes. I made a backing plate for the cylinder end and bolted it tight with a bike inner tube and then used the valve section on the turbo inlet . Pump it up and then spray with soapy water it will bubble up


Since I built mine I have got good at tig and if you can't seal it or decide to make another I'd tack it up how you want it pay a shop to finish it off

 

[Adam1991]

anyone know where I can get 309 mig wire?

 

[Bede]

https://weldspeed.com/midland/contact_details.asp

 

[Richard.]

You need the dissimilar wire which is over alloying so that when dilution with the stainless/mild takes place in therory the weld becomes a low alloyed stainless.
309 is the usual go to flavour and available every where. 312 is also a dissimilar filler. Better for high strength application. For your job a 309 is ideal.

 

[Wendelspanswick]

Looking closely at your photo (it's not a brilliant photo) it looks like you have zero or very little penetration. Ideally the weld should form a slightly concave to slightly convex fillet. Your weld looks more like it was extruded from a mastic gun to be blunt!
I would concentrate on practicing easy pipe to flange welds till you have a perfect fillet and then re attempt your manifold.

How thick is the flange and what mig did you use?

 

[Richard.]

I always admire people for going down the route of trying to make things work themselves. I don't however think your problems with blowing from the welds is just down to the incorrect filler. As rightly said in the post above the welding looks pretty useless all round. Far too cold and inconsistent. No pen at all. I also see gaps where there is no weld. So it's bound to blow if it's not completely air tight. The pipe work and flanges look good but the welding needs sorting out. 3mm is thick for an exhaust manifold your flanges are probably 6-8 I'd guess so your gonna need 80-100 amps for the pipe work and to weld those flanges to the 3mm properly your lookin 150-180amps.

 

[dannyp]

at a quick look as others have said, MORE POWER is needed

very easy with a small mig to sit a weld ontop of thick plate. i allways find it usefull to bolt the manifold to an old/ knackerd cyl head to stop the flanges bending to much