Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   DIY SS Bottom Mount Manifold (https://www.miataturbo.net/diy-turbo-discussion-14/diy-ss-bottom-mount-manifold-40820/)

Gotpsi? 11-04-2009 01:25 PM

Hey I just talk to the head guy at the welding shop, he says to use stainless wire and the tri gas, if you don't want to buy a bottle you could rent one for a couple dollars a month.

wayne_curr 11-04-2009 02:41 PM


Originally Posted by Gotpsi? (Post 477786)
Hey I just talk to the head guy at the welding shop, he says to use stainless wire and the tri gas, if you don't want to buy a bottle you could rent one for a couple dollars a month.

Awesome. So with the trimix do I still need to backpurge? Any specific stainless wire?

ARTech 11-04-2009 02:53 PM

Nice improvisation. SCH10 SS takes long enough to cut on the bandsaw, I can image there was a lot of :vash: cutting with a hacksaw.

What do you plan on doing for the 2+3 runners?

Champagne of beers eh?

vw_nut 11-04-2009 02:55 PM

Nice work!

How was it cutting stainless with the hack saw? I remember burning through a bunch of sawzall blades cutting stainless to build an exhaust.

Gotpsi? 11-04-2009 02:56 PM

No he said that you dont have to back purge with the mig and tri mix

wayne_curr 11-04-2009 02:57 PM


Originally Posted by ARTech (Post 477827)
Nice improvisation. SCH10 SS takes long enough to cut on the bandsaw, I can image there was a lot of :vash: cutting with a hacksaw.

What do you plan on doing for the 2+3 runners?

Champagne of beers eh?

Honestly, hacksawing was not as difficult as people make it out to be. A little bit of exercise, definitely, but not too hard. Keeping it straight is a bit of a challenge.

The number 2+3 runners will be done like Stein/18psi etc. Very simple, semi-straight into the collector. Not ideal, for sure, but I didn't order enough straight pipe or bends to make a full on 4 into 1 merge collector mani. Nor do I have the skill or tools etc.

ARTech 11-04-2009 02:58 PM

Ideally you always want to backpurge stainless. If the weld penetrates 100%, the inside will "sugar" (oxidize) unless backpurged.

wayne_curr 11-04-2009 03:01 PM


Originally Posted by ARTech (Post 477835)
Ideally you always want to backpurge stainless. If the weld penetrates 100%, the inside will "sugar" (oxidize) unless backpurged.

Thats what I thought. Isn't there a paste of some sort that can be used on the inside of the joints to achieve the same effect?

I'm going to go to airgas today and ask them what they think. I'm pretty sure i'm going to end up running trimix with backpurge of pure argon if I end up migging this mani. I'm really wishing I had just gone carbon for this manifold at this point.

Gotpsi? 11-04-2009 03:02 PM

Thats what I thought but he said it wont. I only Tig stainless so back purging is a must.

Gotpsi? 11-04-2009 03:04 PM

I'm going to go to airgas today and ask them what they think. I'm pretty sure i'm going to end up running trimix with backpurge of pure argon if I end up migging this mani. I'm really wishing I had just gone carbon for this manifold at this point.[/QUOTE]

well you can just weld it up with your standard mig wire and gas you have, it will work but it wont be stainless anymore, muffler shops do that all day long. you will just have a shinny mani with rusty welds :giggle:

wayne_curr 11-04-2009 03:06 PM


Originally Posted by Gotpsi? (Post 477844)
I'm going to go to airgas today and ask them what they think. I'm pretty sure i'm going to end up running trimix with backpurge of pure argon if I end up migging this mani. I'm really wishing I had just gone carbon for this manifold at this point.

well you can just weld it up with your standard mig wire and gas you have, it will work but it wont be stainless anymore, muffler shops do that all day long. you will just have a shinny mani with rusty welds :giggle:[/QUOTE]

Lol. I've got the stainless, I want a stainless weld bead =P

ARTech 11-04-2009 03:07 PM

Solar flux is what you're thinking of. It's great for exhausts,downpipes and headers, but I wouldn't use it on a turbo manifold, unless you think you can grind it all off in between welds. The stuff will flake off and damage your turbo.

vw_nut 11-04-2009 03:16 PM

Wish you were closer. I have a TIG, but no expierience with stainless & back purging yet. Just got the welder over the summer. Only done mild steel and aluminum so far.

SKMetalworks 11-05-2009 08:11 PM

I never used tri mix gas. waste of money. Ive actually never even heard of it untill 18psi's build. For aluminum i love using 75/25 helium! Burns hot and leaves great bead formation (especially with pulse) with a shiny weld to boot. Argon gas with argon back purge. Bring some beer and a little bit of cash we can do it this weekend. (Let me know so i can go snag an alternate tank for purge).

BTW i have been TIG'ing for 1 year @ 60 hours a week.

wayne_curr 11-05-2009 08:15 PM


Originally Posted by sbkcocker499 (Post 478679)
I never used tri mix gas. waste of money. Ive actually never even heard of it untill 18psi's build. For aluminum i love using 75/25 helium! Burns hot and leaves great bead formation (especially with pulse) with a shiny weld to boot. Argon gas with argon back purge. Bring some beer and a little bit of cash we can do it this weekend. (Let me know so i can go snag an alternate tank for purge).

BTW i have been TIG'ing for 1 year @ 60 hours a week.

It wont be done by this weekend. Maybe next weekend, we'll see how progress goes.

I'm not causing trouble by tacking it with regular carbon wire am I?

SKMetalworks 11-05-2009 08:25 PM

The only thing is that at the tack there will be a lower chromium content then the surrounding area. We will grind them out before welding over them.

Stein 11-05-2009 10:39 PM

Looking good man. I don't envy you cutting with a hacksaw. I spent a lot of time with my bandsaw, angle grinder and cutoff wheel in the die grinder. The cutoff wheel is your friend when hand coping joints. Much easier to handle with one hand and holding the part in the other.

elsdragon314 11-06-2009 01:16 AM

I've got to say, I am uber impressed that you are able to make those cuts with a hacksaw too, it isn't even one of the high tension frames (which helps a lot for future reference.) I'm surprised the supplies from weirtech were so cheap for SS flanges and SS schedule 10 tube. I'll probably have to order from them, though I am still on the fence of if I want to do it in SS or mild, just because I figure I will be learning as I go, and it is cheaper and easier to learn on mild (though i've got the welding part down... go figure.) Did they sell you the exhaust flange with the bolt holes already sliced for thermal expansion?

Stein 11-06-2009 09:07 AM


Originally Posted by elsdragon314 (Post 478818)
I've got to say, I am uber impressed that you are able to make those cuts with a hacksaw too, it isn't even one of the high tension frames (which helps a lot for future reference.) I'm surprised the supplies from weirtech were so cheap for SS flanges and SS schedule 10 tube. I'll probably have to order from them, though I am still on the fence of if I want to do it in SS or mild, just because I figure I will be learning as I go, and it is cheaper and easier to learn on mild (though i've got the welding part down... go figure.) Did they sell you the exhaust flange with the bolt holes already sliced for thermal expansion?

Two things, the relieved bolt holes is new to me. Might be something they just started or maybe just the stainless. My wiertech mild flange wasn't cut. I have had zero problems with that since I installed it.

Also, I used stainless weld els and wiertech mild steel flanges together. Use 309L filler rod to join the two with no problems. In a year now, I have seen no rust on my flanges to speak of and the stainless to mild joints have held up fine. It's been done by many people before me. Stainless flanges are 3X times the mild steel price.

wayne_curr 11-06-2009 11:54 AM

yes, my flanges are mild steel as well.

In retrospect, getting stainless parts at all was my biggest mistake. I'm pretty much decided on paying someone else to tig it for me which adds more to the bottom line of this project.


All times are GMT -4. The time now is 09:35 AM.


© 2024 MH Sub I, LLC dba Internet Brands