slomx5

I'm looking for opinions on this. I have a 99' Miata that I'm turbocharging. I bought a GT3271 that's going on it. I plan to build a manifold for it out of weld ells, or butt welds. It will be a tubular style manifold. 4 pipes coming up, curve down, and 1&4 will combine and 2&3 will combine right before they get to the divided T3 flange. I'm wondering if I could stick weld this manifold together and it be reliable. I don't want it cracking on me.

I have between 50-60 hours of stick welding under my belt. I can weld decent, but not perfect. I've built a few exhaust systems, a go cart from scratch, little welding on a shrimp boat, and other things. But never built a manifold before. All my research shows TIG is the best, or at least the most common. I'm wondering if stick welding (SMAW) is good enough? Are most manifolds TIG'd in the interest of aesthetics, or is because the joints will be stronger and less likely to crack from heat related stress? Is a good stick weld as good as a good TIG weld? Would the differences be negligible? What would be the best rod to use? Would pre heating the parts before welding help? Or heating them after welding to reduce stres?

Last thing I welded was a 3" header back exhaust system for my car. Used 3/16 7018's with my Lincoln 220. Put about 1200 miles on it and so far, it's holding fine.

Thanks
Patrick

slomx5

From what I'm reading from Lincoln's site and others I should get a smaller 7018 rods. Something like a 1/8 7018. Sound reasonable? Or is there another rod that's better for this application?

TIGboy

im gonna come out and say, you better be a damn good stick welder if you wanna stick a manifold together. most manifolds are Tig'ed because of yes strength, how clean it is and the versatility of a tig torch. I strongly recommend that you either Tig weld it or get someone to do it for you. what material are you planning on using?

TigWiz

If you were going to make a very simple manifold and made it out of steel weld els then I would say go to town. You would probly have to do quite a bit a cleanup work after the fact to make it look presentable, but I could hold up just as well as a tigged manifold.

In your case though, trying to make a long runner split runner design, I would not recommend stick welding. I don't believe it would last, then again I would like to be proven wrong. Good Luck!!

slomx5

I would be using Weld Ells, or butt welds. They are just mild steel pipe. I'm kinda thinking I can do this. I'm not worried about aesthetics as much as I am reliability. Oh yeah, my dad is a great stick welder (like 20,000 hours experience). So I could get him to weld it in his spare time and it would be about as good as a stick weld can be. Though I'd rather do it myself.

Any pointers on what to do/not to do? I've read a few welding books, so I kinda know how to look at the weld and see if I'm going too slow, too cold, or too much arc length, etc. I'm thinking something like get 3-4 tacks, then weld it out between two tacks, turn 180* and weld that out, etc, till it's welded out, being sure to lap the welds together. Then grab the oxy-propane tourch and heat cycle it to relieve any stess in it from welding.

Of course maybe this is a bad idea as I can barely find ANY info on people that have stick welded their manifolds.

Longitudinal

Stick requires a lot of experience to do well, but a properly done stick weld can be just as strong as a weld done with any other technology and *can* look very good. Occasionally, when the planets are aligned just so, I can lay down a pretty nice stick weld, even on cast.

The thing to be very careful with IME with stick is warpage. You'll put a lot of heat into the workpiece with stick, so take precautions to avoid getting it twisted up.

I say weld it yourself. Mild steel els are affordable, so even if you bollocks it up fiercely, you won't be out that much.

i drive a honda

man those welds are going to come out cold, or burn through man, 3/16, especially on a butt weld... :S

TIGboy

I have actually found that some places sell stainless weld elbows cheaper than MS.
I wish you the best of luck whichever you choose. my friend has a turbo miata with a gt28rs on it and he picks on 03 cobras, your setup should be extremely fast.

Longitudinal

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TIGboy &raquo;</TD></TR><TR><TD CLASS="quote">I have actually found that some places sell stainless weld elbows cheaper than MS.</TD></TR></TABLE>

Link, please. You can't say something like that and not provide a link. That's just mean.

i drive a honda

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slomx5 &raquo;</TD></TR><TR><TD CLASS="quote">From what I'm reading from Lincoln's site and others I should get a smaller 7018 rods. Something like a 1/8 7018. Sound reasonable? Or is there another rod that's better for this application? </TD></TR></TABLE>

low-hy will probably be too hot/ too deep for the thinner walled piping, id go for a sheet metal rod. TBH

post pics, even if it comes out crappy.

TIGboy

I live in Detroit we have steel factory's everywhere lol and I work at one...I use to get all my material local. if I can prove it some how, I will.

Top Ramen

My .02 --&gt; borrow a Mig.

i drive a honda

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Top Ramen &raquo;</TD></TR><TR><TD CLASS="quote">My .02 --&gt; borrow a Mig.</TD></TR></TABLE>

even cheaper/easier FCAW that son-bitch

punkinbeck

3/16 7018 on exhaust?? wow thats a little much, dont know how you did that but I give you credit.
Personally I think stick can be just as strong as tig if done right.. It will be very difficult. normally on larger pipe i'll run a 6010 root with a 7018 cover but I would never attempt a manifold with it.. You could always try it on some scrap and see how it turns out.. If i were you i'd get it all fit up with stick and then go somewhere that has a mig/tig and weld it, or get them to do it.. good luck!!!

Garage 808 Hatch

as for the manifold, what do you people think weld el's are actually used for in industrial applications? Plumbing and pipefitting. guess what method is used to weld these in most instances? Arc welding.ive seen some fitters that can lay bead with arc welders you would think are machine made, some of these guys are amazing. just my .02

jzz30

yea i've also seen a stick welder lay a bead like a tig

Agtronic

Good pipe welders can do wonders with stick, and it is still a very sound welding method. My concern with you stick welding a tubular manifold is not with weld strength, but how the hell are you going to get into the tight spots. It's already difficult with a TIG torch that you can stick the tungsten out on, or even run with no cup and an external argon source. I can't even imagine doing the last weld on a collector with a stick.

Just my $0.02 ...

i drive a honda

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Agtronic &raquo;</TD></TR><TR><TD CLASS="quote">Good pipe welders can do wonders with stick, and it is still a very sound welding method. My concern with you stick welding a tubular manifold is not with weld strength, but how the hell are you going to get into the tight spots. It's already difficult with a TIG torch that you can stick the tungsten out on, or even run with no cup and an external argon source. I can't even imagine doing the last weld on a collector with a stick.

Just my $0.02 ...</TD></TR></TABLE>

he can probably maybe do the major parts, bends, easer welds with stick then maybe just mig/fc the rest?