I need to make a new dump tube after getting a new manifold over the winter.
So I ordered a 2ft 1.5" U bend in 304 stainless but it's 18 gauge.
They didn't carry it in 16g in that length. Dump tube will be braced from the block.
Personal welding it is very experienced. So my question is 18 gauge will work okay?

 

You already bought it, just make one

 

Yes, but I was asking is 18g going to be good enough. Seems like every where I looked at 90 degree bends they were 16g.

 

It will be fine. If you do brace it, be sure to run a flex, or else something will crack somewhere.

 

Exactly what I was looking for. Thanks I appreciate it. So I don't even have to brace it then? I figured with the length of the dump tube and just the one weld at the flange and vibrations from billet mounts and wheel hop. That I should run a brace somewhere so it doesn't crack at the main weld.

 

i wouldnt brace it. 18 guage will be fine.

 

If you are truly worried about it, brace it to the block so it rocks with the motor, not to the chassis

 

Dump tubes are the #1 failure for fabricators. Long tubes act as leverage for the engine vibration. I think it's good to brace them, but even if you brace to the motor, expansion will usually cause failures. So brace to the motor, and run a flex, then you're good.

 

Alright sounds good. I just didn't wanna waste $40 on a mandrel bend that was useless.

Yeah that was the plan. Use one of the holes from the Ac bracket that I took off but I'm not going to brace it now. Seems like it's not needed from what you all are telling me. Thanks for the heads up though.

 

Ive made headers out of 18g, as long as you have full penetration and make sure you back purge I wouldnt see you having an issue, just kep the length down a bit if possible.

 

Exactly. We hardly ever brace tubing actually. No problems thus far. Most our headers are 16g but when trying to remove every oz we can we use 18g.

 

Yeah my girlfriends dad is welding it up for me. He's been a welder for over 22 years now so I'm sure there won't be any penetration problems. He will be using a tig welder but I doubt he will back purge it. I'm sure it'll be just fine. If not I'll tackle the issue when it happens.

 

Yeah, really the only thing you need to do is use slip fits and it allows it to do what it needs, headers are long and heavy, so a standard dumptube should do fine. But to the OP, I would back purge it, your not working with much material and nothing is worse then running your dumptube over

 

I'll ask him about back purging it and see what he says. I'm not worried about the welding part honestly though. He has tons of experience so I'm sure it'll be okay. I also just thought back purging cleared the area of any contaminants so the weld on the inside would be cleaner and not have any crystals/sugar? For a dumptube that's blowing gases outward I wouldn't think it should matter?

 

^^That sugar is what will make the welds fail.