3'' Stainless exhaust build ......tips or tricks help needed

[6600DURAMAX]

Looking / Working on first exhaust build for the K5 - going with 3'' stainless with an X pipe and Borla ATAK mufflers

FYI - for those with LS swaps and want full length headers - Speed Engineering headers will fit with minor trimming ...

Questions that I have -
1. any suggestions for mounts ? the exhaust seems to be around the same plane as the frame so hard to "hang" the exhaust

2. currently only have a stick welder so being really careful as I tack up using some 308L rods - any tips on this ( other than get another welder...)

[6600DURAMAX]

Minor trimming needed on passenger side

[SkidmoreGarage]

I started this project as well, but not on a blazer.

Hangers: Build your own using bent solid rod and OEM style rubber isolators. You can place them anywhere you want them and at any angle.

Materials and welding: my opinion is that if you intend to stick weld, then I would use mild steel and use the material cost savings to buy a cheap mig. There is a reason that no one uses stick welding on stainless exhaust tube. If you intend to tack and then take it to someone, then that is a different story. Also, buy extra bends and put the exhaust exactly where you want it.

[6600DURAMAX]

first attempt at tack welding .... hahah, but the second one was much better...

Haven't had a chance to try to run a bead yet. The tacks however seem very legit !!

[6600DURAMAX]

This is burning a 308L 3/32'' rod, had to set to 75Amps - purchased some 1/16'' rods hoping to be able to turn down a little to prevent blow through....

[Accelo]

Wow, one amazing high end build. Will the transfer case be electronically shifted?
When doing a custom exhaust a metal cutting band saw is a life saving tool.
Looking at the quality of the rest of the build you may not likely be happy unless the exhaust is tig welded.
Their are welders that could weld this with stick but they are very few of them and the fitting would have to be perfect.

If you are not tig proficient consider tacking the system together and getting it finished tig welded by a pro.
BTW Your Tacks look nice.

The issue with stainless is it grows so much more than steel when it's hot.
Linear Expansion Coefficients for stainless is 17.3 and steel is 11.
With a 300 deg difference in temp between hot and cold a 12 foot section of steel will grow about 1/2" and the same length and temp in SS it will grow 7/8".
I just guessed at a 300F deg average. It could be more especially if you consider the headers and I could be low on the temp? Point made.

[6600DURAMAX]

Looking to go and buy a harbor freight horizontal bandsaw today .....

Agree that finding someone to tig it would be the best - current goal is to get everything aligned and test fit - then remove to have it welded up. I'll keep looking for someone close to tig it for me. Waiting on remaining exhaust tubing before I try to tack to exhaust pieces together. The split flanges are pretty easy to tack as they are thick, concerned about the exhaust tubing....

Will try to run a bead this weekend if the 1/16'' rods and rest of exhaust tubing shows up.

Plan on manually shifting the NP208 - potentially using a JB Custom Fabrication's cable shifter

[BASE]

I'll be tuning into this one. I have a big pile of 3" stainless I'm about to try and create an exhaust system out of as well. I was cheap and bought the 400 series stuff so not sure how much that changes things.

20yrs ago I tried MIG welding some stainless exhaust at work and got my butt kicked. Seems like I ended up using a series of spot welds. I just couldn't run a bead to save my life.

[SCOTI]

I used standard style exhaust hanger parts for the systems I've done. You just have to get creative w/them.

For some hangers I used SS housed/encased rubber bushings & some solid 3/8" stainless hangers from Summit Racing. For others, I made tabs from mild steel that are bolted to the frame or x-member that use 3/8" SS bolts as the actual hanger (2 nuts secure the threaded end of the bolt to the tab/bracket; the 'head' of the bolt is cut-off & rounded so a bushing can slide over it). Others were SS tabs welded to the piping & used standard 2-hole rubber coupons found in generic parts store mild-steel exhaust hangers (I cut them apart for the rubber pieces).

I made sure the hangers allowed the system to move fore/aft for their expansion. How much expansion is based on how long the 'runs' are. I don't even have those expansion/flex joint pieces & haven't had any issues w/my dually but the system does have the ability to grow slightly in length. My experience w/SS tubing (.065" wall) is most stuff under 48" lengths won't be much of an issue as long as you're not locking the system in place.

Some shots of the hangers on my 64 (pg.33 post 807 - 816):
http://67-72chevytrucks.com/vboard/s...d.php?t=381425

Some from the dually can be seen on the 1st page:
http://67-72chevytrucks.com/vboard/s...d.php?t=640843

[k5blazin]

[QUOTE=6600DURAMAX;9062375]Looking / Working on first exhaust build for the K5 - going with 3'' stainless with an X pipe and Borla ATAK mufflers

FYI - for those with LS swaps and want full length headers - Speed Engineering headers will fit with minor trimming ...

Questions that I have -
1. any suggestions for mounts ? the exhaust seems to be around the same plane as the frame so hard to "hang" the exhaust

2. currently only have a stick welder so being really careful as I tack up using some 308L rods - any tips on this ( other than get another welder...)[/QUOTE

Mounted to my skid plate crossmeber. Hope you can see in the pic. Also yes buy a tig!

[k5blazin]

[quote=k5blazin;9062761]

Originally Posted by 6600DURAMAX

Looking / Working on first exhaust build for the K5 - going with 3'' stainless with an X pipe and Borla ATAK mufflers

FYI - for those with LS swaps and want full length headers - Speed Engineering headers will fit with minor trimming ...

Questions that I have -
1. any suggestions for mounts ? the exhaust seems to be around the same plane as the frame so hard to "hang" the exhaust

2. currently only have a stick welder so being really careful as I tack up using some 308L rods - any tips on this ( other than get another welder...)[/QUOTE

Mounted to my skid plate crossmeber. Hope you can see in the pic. Also yes buy a tig!

[LS short box]

Back in the day when I was a line tech at a chev dealership we were the first in the area to have a pipe bender. Yeah I'm that old. Our training was the first exhaust hanger was at the rear of the muffler. That length gave plenty room for engine movement.
Totally your build but those flex couplings aren't really needed. I'm guessing you have poly engine mounts so the engine isn't going rock back and forth much if any.
On the X pipe I would rather see the exit side not expanded. The down stream tube/muffler should be expanded so it's fits over the upstream side tube. Helps seal the connection.
Just my .02. Looks like a great build. Good luck.