S10 pipe welding for exhaust manifold need tips

[jabran200]

Hi guys/girsl

I want to make a custom turbo exhaust manifold for my car for a turbo which isn't common so nothing available on the shelf.

I've got some 1.25" dia 304l s10 pipe to practice with. I have mostly ever done aluminium with my tig like intercooler pipes, brackets etc.

I am struggling a little bit with the S/S but I think I am alsmot there just need some guidance

Using a 1.6mm red tungsten, I think I need to use 1.0mm but only had 1.6 red to hand.

I wirebrushed the bends and then did some welding, I realised I was using too many amps so put the tig to maximum of 60-70 amps but using a foot pedal to control the current. Previously I was using far too much heat.







I did touch down a couple of times, I really need to get a stool lol.
Any tips, advice and if you can point out issues/probems and how to try and resolve them would be great.

Thanks

 

[Rrunnach]

Concave welds, you need to reinforce/cap...............

 

[jabran200]

Was just a practive without filler as I only had 1.6mm filler rod which needed too much heat to melt into the pool so I decided to just practice getting a decent colour and weld. The edges were veed too.

 

[Paul.]

Pretty pointless trying to join shed 10 pipe without filler, what you have achieved is as good as it will get, use a 1.6 tungsten, and a 1.6 filler at about 60 to 70 amps, with the joint properly prepared with a vee, I would probably leave a 1mm gap and keyhole the root. even better purge the job as well, but not absolutely necessary. aim for a flat or slightly convex weld with the toes properly fused in and no undercut, you should be able to nail 3mm in one pass but a root and cap is ok.

 

[jabran200]

Initially I was finding that i needed to much heat for 1.6mm rod but i nevere tried after i turned the amps down will give it a go tomorrow. I'll try and do it in one pass and see how it goes. I was meant to do it with a 1mm gap but totally forget when i clamped it.

What do you mean by keyhole and toes? new to the technical terms.

Also what do you think about the colour i see some people has nice bluey gold colour is that using less amps than I am

Cheers.

 

[Paul.]

Toes are the edges of the weld bead where it joins the parent material, key hole in the root is a method of achieving penetration in butt joints, exaggerated in this photo but gives the idea,
a read through the tutorial may be useful,

 

[Jimmy-P88]

This is hopefully something I want to aim for with a little more practice myself, what are the specs on that pipe and where can I get it from?
Currently only able to find mild steel flanges for my application, would this cause a problem if I were to use ss pipe?

 

[jabran200]

Thanks Paul. I have been through the tutorial but it has been a long time so I will go through it again.

Jimmy, My neighbour who is metal fabricator orders it in for me I am using sch10s 1.25" pipe.

Also what is the target colour I have read a straw colour is best but then I see manifolds and exhaust with blue in them?

I was wondering the same about the mild steel flange, I have read conflicting stuff about M/S. I know it is done and you have to use 309 filler rod, M/S warps less so you don't have to machine it after welding.

 

[Georgie]

in my opinion the color looks great! Mine always get grey and most members say im using too much heat...

looks as tho all you need is filler and your better than most on here!

Keep us posted on the build and why don't you use a stainless flange?

 

[jabran200]

I plan to use stainless if cost is decent enough my neighbour is going to get me a price on one once I draw him the flanges in CAD.

I tried to weld using what I believe is stamped as 1.4 stainless which I purchases a coupls of years ago to practice in small starter pack and tried it but I found that I needed a lot more heat to get it to melt and turned the weld grey. Anyone experienced this, I'll post pictures up later.

I have the option to order 1.0mm in 308l or 0.8mm in 316l, My stuff will all be 304 though I think it should be o.k with the 316 filler rod or is it a bad move?

 

[hotrodder]

316L will be OK. You shouldn't need to machine stainless flanges after welding if it's done right and while mild steel is less prone to distortion you can still banana the flange if it's done wrong. Search the TIG forum for exhausts and you'll find several threads where it's been covered. Good one here... http://www.mig-welding.co.uk/forum/showthread.php?t=23592&highlight=arc+length Note that while 1mm filler/tungstens often get mentioned it's typically in relation to 1.5mm wall tube rather than sch 10 pipe which (tiny dia stuff aside) is thicker wall and so needs more amps (or gaps/weld preps) and more filler wire as said

Don't get too hung up on colours, especially at the expense of everything else. They're the result of the hot metal oxidising and as the oxide layer thickens it refracts light differently resulting in various colours. Yes, it can be important as it effects corrosion resistance which is why ANY colour is often removed with pickling paste and the like for applications where corrosion resistance is critical/hygenic work etc. The amount of total ******* written about weld colour on forums (especially certain US welding forums and many car forums) is amazing.
A car exhaust manifold... entire thing will be covered in surface oxides the first time the engine is run in anger