Need tips fitting up stainless exhaust tubing

[V-10 Killer]

I need to pick everyones brains a little here. I'm going to be starting to fab up some stainless turbo and exhaust piping in the near future, and was wondering if I could get some pointers on working with thin wall stainless tubing.
I know fit-up is crucial for a good weld, but what's the best way to dial in the fit-up without overheating the metal? This will be 16ga (0.065") 304 stainless. I don't have a tube notcher jig, so I'll probably be doing most of it with coping template/cutouts. I heard someone on another forum mention putting your portaband blade on backwards as to not work harden the stainless while cutting. Any thoughts on this? I don't have a cold cut saw, just portaband, 4 1/2" angle grinder, and air grinder.

I know that backpurging would be highly beneficial for corrosion resistance.
I know heat control vs. travel speed is super crucial.
Being an exhaust and not a food service pipe, I should be able to weld using "lay wire" just fine to keep the speed up, right?

I've had fun learnin the basics with mild and aluminum but this is a whole 'nother ballgame.

 

[shiftdrift]

You can use the 4.5" grinder to rough it in, and a file to final fit it. You want fit to be as perfect as possible if you're tig welding it.

 

[shiftdrift]

P.s. I always individually dip all my tig welds for strength. Instead of "laying" and burning it in.

 

[bullnerd]

I'm not a welder.
I have done some stainless headers.
Not sure why you need to cope them?
For 304,if the fit is right,you dont need filler
I would not even think about doing this without a belt sander that is wider than the tube your using.You NEED nice square ends.
I use a fine pitch(forget the TPI)bi-metal blade on an old Delta 14 bandsaw. Never had a problem with cold working. You have to cut it though, dont rub it to death!
Make a jig for the saw,make it easier to cut "square" on the radius.
Read this thread and especially everything ZTfab says!
Watch the vid,very good tips on back purging,etc..
Practice on some scrap,its easier than most will say.
If you have gaps,you'll get in trouble real quick.
HTH.

http://www.offroadfabnet.com/forums/showthread.php?t=4157

 

[shiftdrift]

I stopped reading at I'm not a welder. Its obvious. I'd never fusion weld anything that will be holding weight. Especially a manifold setup that will be under high stress. Who knows, I Also warranty all my work from defects so what do I know. And yes, a grinder will work fine, once again, if you know what you are doing

 

[zkling]

Wow shiftdrift, chill out dude.

I stopped reading at I'm not a welder. Its obvious. I'd never fusion weld anything that will be holding weight.

It's pretty obvious by that statement that you don't know what you are talking about.

V10, I too have done a few turbos for folks. (Cuss mid 90's civics). Fit up is key. I usually use a horizontal bandsaw to cut material off. Then dial in exactly with either the belt sander, file or a small disk on the air grinder. Usually a combination of all three. Just take your time and go slow as you sneak up on a perfect fit. No real special tools needed just a bit of patience. Think every cut out beforehand. If something needs to be bent, bend first then cut at the proper place.

As for welding stainless, especially thin stainless. What tig machine are you running? I usually run 1/16" cer (orange tung) sharpened very fine with a gas lens. The gas lens really helps to get good gas coverage at all angles. If you get sugaring you are not getting enough gas coverage. I usually use 0.045 or 0.030 filler or even no filler. You can backpurge if you like, there are also a few fluxes on the market that prevent oxidization on the back side of the weld.

 

[bullnerd]

Mr.Drift..I hope you dont take what I posted as any kind of defensive response to your post. I just kinda type what pops into my head. More info, less conversation.

The "i'm not a welder" statement is to make it clear,I dont pretend to be a welder.

 

[shiftdrift]

Yeah...actually I do as I'm a certified tig welder. I have been a fabricator on automotive stuff for several years as well and never have I fusion welded. I'm perfectly chill just when people say a grinder won't work if you don't have the proper tools that's just being lazy. Nothing a grinder and a hand file can't match for notches.

 

[bullnerd]

Wow! I never said a grinder would not work.

 

[shiftdrift]

I mis read. I thought you said grinder. Not belt sander. Apologies.

 

[theknurl]

V-10 Killer;

are you talking 16ga 304 for the exhaust or intake side?

304 goes away in intermittent use at 1500* how hard are you going to run?

i use Schedule 80 for the exhaust side, it will support the weight of the turbo

16ga SS will work fine on the intake side

try to make the best cut you can......i use a 16" Apex to square it and then fusion weld it

i made prototype 2 stroke pipes for FMF for ~20 years.....

the record?

51 cones in 50 inches

 

[V-10 Killer]

Thanks for all the info thus far guys. It'll be nice to have this as a reference when I'm ready to start sizing up pieces.

For a little more info, I'm jusing the 16ga 304 for the charge pipes and downpipe, and it'll be ceramic coated inside out and wrapped. I'll only be running around 15psi of boost and I don't think I need 321 yet for where I'm at. The charge pipes to/from the air/water intercooler will be aluminum.
I'm not running solid motor mounts in this build so the turbo will be supported by it's own support spanning the front frame members, with flex couplings on the charge pipes. If it were a smaller turbo I might hang it off the pipes, but this one's pretty big
I know the charge pipes will be 2.25" with v-bands, the downpipe will be a 5" to 4" cone to 4" pipe. Not sure yet on the wastegate and blowoff valve yet.

As far as the welder, I'm using an Everlast 205 inverter tig. I've been practicing on other metals. I'm doing ok, but I intend to have more practice and a smaller torch before I start this project. I'd heard just a tiny bit about the anti-sugaring flux but haven't read up on it yet. I figure I can rent koditten's spare tank and regulator if I need to backpurge.

 

[V-10 Killer]

I guess I should also start researching to minimalize warpage too...

 

[shiftdrift]

I have an ever last 200dx. Great machine. I get great results with it.

 

[shiftdrift]

As far as warpage. Just move quickly and don't weld more than a couple inches at a time. Aluminum is tricky learning but once you get it down its cake. 16ga aluminum to a v band weld is also tricky. Focus the torch on the v band a little more.

 

[zkling]

That looks under filled, filler dabs too far apart, not consistent, and evidence of tungsten contamination. But then again you are "certified" so....

V10. I am not real familiar with that machine, but have seen people produce some good work with it. What size torch are you running now? I would really recommend a gas lens for proper coverage. I typically run a WP17 air cooled for small, low amp stuff like this.

As far as warpage is concerned. You really want to use as little heat as possible. One thing nice about stainless is that the colors will let you know real quick if you have problems with the weld. I usually tack in 4 places around the tube then weld segments as they are accessible before repositioning.

One other thing. I saw where you mentioned about renting a second tank. You can run 2 lines off of a single tank, one for welder and other for backpurge. The flux is nice when you can easily reach the back of the joint, which is usually the case with these type of builds.

 

[shiftdrift]

Its intercooler piping for a 750whp is300. And its definitely not underfilled, maybe the picture makes it looks that way but the welds have no dip to them at all. The point in the middle is a stop/start point.This is also a lap weld not a **** weld. Yes, sure am, x rayed and all.

 

[V-10 Killer]

Right now, the machine I bought came with their default torch. A "european" wp26 torch:

It's pretty big for me, and I'd like to get a smaller torch regardless.

I'd thought about dual feeding off a second tank too, but the cost of the regulator/dual flow meters and all got me thinking about just borrowing one for a month and sending it back full. It's still a possibility, but every $4-500 I spend on welding supplies is gonna be $4-500 less to put at the car I gotta make sure I'm gonna need it enough to justify it.

 

[zkling]

Ouch, yea the WP26 is pretty large. Does that have built in thumb amp control, looks like it. Do you have a foot pedal as well? If you want to stay air cooled I would look at a WP17 or smaller. You will give up amperage capability, to gain a smaller air cooled torch, but since you really don't need high amps for what you will be doing it should be a good tradeoff for you.

As for the dual output regulator. I believe a member on here is selling brand new victor flow meters for $100, which is a really good deal. Compared to new cost. It was posted in the garage sale forum. What size argon tank do you currently have?

 

[steel 35]

I will step out and say your portaband is in the top three ways of cutting but there are guides for the size tubing your cutting that really work well for 90s; tight chop saws fit in there but the George Fisher's are the top of the line but very spendy. The 12" Disk sanders work great for clean up if needed. I have included a few pictures of junk around my shop that may give you Ideas for the argon issue and a picture of the inside of a tube properly done. I usually MIG the exhausts for friends they can't afford the tigging

http://www.techsouthinc.com/pipeclamps/sawguides.html

 

[steel 35]

Putting your portaband blade on backwards?

NO use the fine tooth and run it a little slow, but keep pressure on it.

 

[V-10 Killer]

Yeah, as far as the torch goes, the welder only puts out 205ish amps. I'd seen that CK flex loc torch a few times and they have a water cooled torch that's rated for 230 amps. I'd just need to fab up a water cooler. Then I can use it aluminum welding too. I figure it'd be my welding version of my sleep number bed. Buy one and adjust it until it's right as opposed to buying multiples and hoping you find what you're looking for.
I'd thought about teeing off of my regulator with a second flow meter, I'm just not sure if I want to dedicate the $$ to it yet.
And as far as the portaband blade thing, I don't remember where I heard it, just forum jumping, but I'll make sure to do as everyone recommends.
And this showed up in my weldingtipsandtricks e-mail subscription a few days back, it has an interesting little trick towards the last third of the vid about correcting (somewhat) warpage on stainless steel.
http://welding-tv.us2.list-manage.c...6a01e5c167b0221e97&id=b15d54d8cd&e=839db3f71b

 

[bgarrett]

My son built a pipe frame dune buggy without a tubing notcher. He used a bi metal hole saw from Home Depot in a drill press

 

[bullnerd]

I asked this is my reply, why do you need to notch to make headers?

How many notches do you need to make turbo headers?1 or 2?

 

[theknurl]

V-10 Killer;
i use a WP-20 torch for almost everything......i have a bendable torch for putting dividers in intake ports

forget back flowing, get some San Diego Mud at your welding supply house. mix it up, paint it on, let it dry and have at it

when buying TIG torches ALWAYS get the long cables