I just need to tack it.. Then ill TIG it..

 

yes... i think you use 100% argon and stainless wire. i know that you can just mig stainless if you have the right setup becasue a friend of mine miged a stainless exhaust up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Want2race &raquo;</TD></TR><TR><TD CLASS="quote">I just need to tack it.. Then ill TIG it.. </TD></TR></TABLE>

Thats how I built my manifold!

 

Typically you use a tri-gas mixture for mig'ing
stainless, if your just tacking, you could just use mild steel wire.

 

I've had bad luck tacking stainless with mig and then doing the full weld with tig. The mig tack is usually twice the size of a tig'd bead so it looks odd and also sometimes the mig'd tack contaminates the tig weld (not sure why?).

Just use witness marks and tack it on the bench.

 

I usually grind most of the tack off with a cutoff wheel and tig right over it.

 

just use a sharpie and mark it, then tig it...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rpm11 &raquo;</TD></TR><TR><TD CLASS="quote">I usually grind most of the tack off with a cutoff wheel and tig right over it.</TD></TR></TABLE>

these little (32mm) re-enforced cut off disks kick *** (i've also seen them at the dentists office..), i have access to an air grinder with great blades, but use these instead. You can grind the tacks right down, or right off with fine precision if you make a mistake. I've also barrowed some high quality grinding tools from the tool/die department at work



What exactly are you trying to do?

 

So Essentially you're saying I could use the cheap Decastar mig on sale at Princess Auto for $180 cdn and use mild steel to tack and then TIG it with my 180SD? That would be so much easier especially when working alone and under the car. Hard to operate the pedal when laying down on your back.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jays91DXhatch &raquo;</TD></TR><TR><TD CLASS="quote">So Essentially you're saying I could use the cheap Decastar mig on sale at Princess Auto for $180 cdn and use mild steel to tack and then TIG it with my 180SD? That would be so much easier especially when working alone and under the car. Hard to operate the pedal when laying down on your back.</TD></TR></TABLE>

hmm.. no.. those welders are for hicks lol

A cheap 120vac welder will send you to an anger management class in a hurry. I would never buy anything less than a 220vac MIG w/gas. My opinion is that it's already hard enough to do automotive stuff with a MIG, so you can't expect a sub par MIG to do the job.

I ran 240vac to my garage and barrowed a Lincoln mig w/gas off of a friend. I would never use mild wire on a stainless.. it welds fine but it defeats the purpose..

 

YEah, didn't think it would be that easy.

I sold my Lincoln 220V gas mig and bought the TIG..I should have kept the MIG too.

 

I need to do something like this :
http://russmarshall.com/d/1372...da531
but wanted stainless

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jays91DXhatch &raquo;</TD></TR><TR><TD CLASS="quote">YEah, didn't think it would be that easy.

I sold my Lincoln 220V gas mig and bought the TIG..I should have kept the MIG too.</TD></TR></TABLE>

If a TIG is all you have: A witness mark works great. I wouldnt go out a buy a MIG if I was you. I know where you're comming from though, you dont have 3 hands to tack with a TIG or would have to take things apart to tack(TIG) it with your marker reference. maybe taking out the engine and putting it on an engine stand will makes life easier?

If a MIG is all you have: (from an amatures point of view) A witness mark would only be good if you did something simple (or two peices at a time).. It would be very difficult to build a manifold, dp, IC pipes or exhaust on witness marks alone (unless you did a couple peices at a time and went back and forth to a shop that could tack(TIG) it for you) - you have to tack things progressivly, if you are a hair off than you're pretty screwed for your next 'peice of the puzzle'. Taking a pile of marekd up bends to a shop to TIG it would be near imposible to get the fitment bang on. I had to cut off tacks a few times to tweak some of the runners - I'm sure this is normal for header fabrication? I did however, use witness marks to progresivly tack(MIG) many peices together - but I wasn't going to run to a shop to tack(TIG) it for me.. tack(MIG) and grind worked out great for me..

Also, you can do very creative things with vice grips or hose/hoseclaps and *cough*<FONT SIZE="1">tape</FONT> to avoid having to take thigns to the bench to tack them. On a side note: A high quality wide masking tape works EXCELENT on aluminum IC pipes for fitting up the bends.. when you get it right you just cut good size holes to tack them together. Take the tape off and give it a good cleaning.. then you're ready to weld them for good. I built my IC pipes in my garage at home without a single tack!

I'm going all over the place with this reply.. I hope I'm not being confusing.. lol Also, I am not a fabrication expert, i am just to stobourn to pay someone to make something for me for my non-conventional setup.. these are my opinions and what has worked for me! Experts, please correct me if i'm wrong about anything.

 

I've had customers bring me exhaust systems to weld up all taped together with masking tape. That stuff really works wonders!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jays91DXhatch &raquo;</TD></TR><TR><TD CLASS="quote">So Essentially you're saying I could use the cheap Decastar mig on sale at Princess Auto for $180 cdn and use mild steel to tack and then TIG it with my 180SD? That would be so much easier especially when working alone and under the car. Hard to operate the pedal when laying down on your back.</TD></TR></TABLE>

I think that works fine I tacked a whole exhaust under a car with the lincolin 120v mig from can-tire, then tig it with a dynasty. I sold the mig-pak to help get the tig but as soon as I get some money I will get a cheap mig again.

+ it's nice to have if you need to tack stuff up outside your garage...in the middle of say winter lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">I've had customers bring me exhaust systems to weld up all taped together with masking tape. That stuff really works wonders!</TD></TR></TABLE>
We've done that before since none of us can TIG weld. We tape the entire compilation of bends together while mocking it up, and then use a razor blade to cut out sections of the tape so that the weldor can tack it by TIG welding on his bench, then he goes back to finish the welds around the circumferences.

It seems like it would be very hit or miss, but it's seemed to work well enough that we've never had to redo a section before.

 

If you tape them up good then they won't move, so it's only as good as your taping and lining up to begin with.

 

damn you guys.. I thought i came up with a home-fabrication breakthough only to find out that everyone is doing it..

 

thats why i love my smiley tig.

hf button start makes it soo easy to tack parts while mocking them on the motor.

 

Yea you can definately mig stainless...ive been doing it at school for weeks practicing for my welding test for Roush Racing!

I wouldnt recommend tig'ing ove a mig'd tack. It seems like it always contaminates it(especially if you didnt use stainless filler). Id recommend getting a torch with a fingertip control and tacking it all autogonously(sp is prolly way off on that one)...which is just welding without filler. If you do it that way itll definately hold and you wont have to worry about grinding down any tacks before you weld it up. Good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccfab &raquo;</TD></TR><TR><TD CLASS="quote">thats why i love my smiley tig.

hf button start makes it soo easy to tack parts while mocking them on the motor. </TD></TR></TABLE>

Starting the arc isn't the hard part. Does your hf button add filler for you while you're holding the torch and the part?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">If you tape them up good then they won't move, so it's only as good as your taping and lining up to begin with.</TD></TR></TABLE>

My brother sent me an intake manifolds all taped together how it needed to go...made it from NY-&gt;AZ in one piece, got it, welded it up and sent it back...you can see how close it is to the alternator that it must not have moved much lol.