I'm building a Y-pipe for my challenge project, and most of it is uncoated steel, in order to be welded easily. Ceramic coating is not in the budget, obviously, and even the home kits are out, as I have no way to bake it consistently, and it is doubtful I'll be able to follow the directions of heating it up on the car, since I can't guarantee I'll want to run the car any particular length of time while debugging it.
So, given those limitations, would cleaning the remaining oil off the tubing with mineral spirits, then hitting it with BBQ paint actually help slow down rust, or is there something else equally simple I could do to cut down the chances of this thing rusting quickly?
Bbq paint held for 2 years on a daily driven truck i had. I generally spray challenge exhaust with whatever almost gone can of high temp engine paint is laying around
By whatever sorcery, I've found that 14 gauge seems to last longer before rusting than 16 gauge. It also helps if you orient the tubing so the seam isn't the low point. I make exhaust out of 14 gauge whenever I can.
It's probably not Challenge-worthy, but I usually make Y-pipes out of stainless. Stainless doesn't bend worth a flip so I don't use it for bending up exhausts, but Y-pipes I piece together by chopping up mandrel U-bends. Summit shows mild U-bends for $22 and 409 stainless for $40, in 2.5".
I bought the cheapest mild steel mandrel bends that Speedway sells. Don't really have s good setup for welding stainless right now, maybe in the future.
I'll keep in mind trying to keep the seam up high, at least on the parts I haven't finished yet.
The truck is unlikely to see much winter, but with Ohio being like it is, salt has pretty much permeated the roadway surface, so it'll see at least some salt no matter what I do.
I'll have to see what I have laying around, think I have some BBQ paint already, but if not, I'll grab some engine paint when it's all done.
I MIG stainless with ER70S6 wire like everything else. Seems to weld easier than using proper stainless wire. You just need to pay attention to how much heat you're putting into the metal especially with a butt weld. Stainless doesn't transfer heat very rapidly so it is very easy to burn through once you get going, need to do a lot of moving around and waiting for things to cool off.
I like to use zinc weld-through primer on exhausts. It mimics almost perfectly the coating on vintage BMW exhausts, and seems to resist rust pretty well.
I have used cold galvanizing paint with readable success. It will smoke at first but I put it on heavy and I think it just burned away everything but the zink. Far from perfect and the further down street you are the better it seems to work.
dean1484 wrote:
I have used cold galvanizing paint with readable success. It will smoke at first but I put it on heavy and I think it just burned away everything but the zink. Far from perfect and the further down street you are the better it seems to work.
You can get a similar effect by spraying antiseize onto the exhaust.
High-temp engine paint works decently....better than it does on actual engines, in my experience.
Do you have a flux core welder? You can get stainless flux core weld wire, for future exhaust work.
I have tried to find one and no perfect solution yet. VHT High-Temp Exhaust paint was very fast to burn off a pipe right after the header.
The POR-15 High Temp paint has done somewhat better and stuck fairly well, but still not everywhere. It was easy, though, I just slapped it on the tubing after cleaning it with wax remover. I was also using the Speedway 16-gauge mild steel pipe with the black transport coating on it, and I didn't try to remove any of it before I applied the POR-15. P.S. it smokes off pretty noticeably on the first couple engine runs so do that outdoors, if you try it.
