Good high temp epoxy

I'm wondering if anyone knows of a good epoxy that can be used inside a header? I know people have used it to raise the floor of the exhaust ports. I'm just worried about expansion/contraction and the epoxy coming off and going through the turbo. Will it be okay? What kind/brand should I use if at all?

A little more info on what I'm actually trying to do:
I'm in the process of building turbo headers for my 3.0l van. I am making log headers out of 1-1/2" schedule 40 pipe(which just so happens to be the perfect size to match the 3.0l exhaust ports). I only have access to basic tools. Angle grinder die grinder flux core welder. The headers are made from 90* weld els and schedule 40 straight pipe. I have one completed minus the flanges and I'm pretty happy with that one. On the second one I have two runners done but I decided to try a slightly different way of cutting and it didn't work out as well. I had a gap to weld and on the inside the gap is evident. I would like to smooth it out if possible but I don't think I can make a good weld on the inside to add enough metal. Which is why I'm considering epoxy. I would hate for a piece of epoxy to break loose at some point and destroy the turbo so I am posting here in hopes that someone has tried it before. If not I will use my die grinder to get it as smooth as possible and run it. The gap is not horrible. It's just not as smooth as I would like it to be. I'm probably being too anal. With the radiator I'm using I don't have enough space to make tubular headers which is the main reason why I chose to make the log headers. I think using 90* els welded to the straight pipe will flow better than using tees so that's the route I'm taking.

Thanks
Joe,

Unless they are super cheap ebay turbos, I wouldn't chance it. Weld it up or start over.

In the intake I'd not hesitate, but the exhaust is a whole different kind of hell for an epoxy to try to deal with...

Just my .02 worth, best of luck with the project, should be quite fun when you're done!

Mike

Never heard of an epoxy that could stand up to the rigors of an exhaust port.

Thanks for the input. Even if an epoxy could stand up to the heat, I imagine expansion/contraction would make it difficult for any kind of epoxy to stay put. I'm going to try and weld it up but, like I said if I can't get it perfect I'll just live with it. It's not like there isn't enough weld there to hold. Just an unwanted crevice in one small area. I am using a cheap ebay turbo. I know, I know, you get what you pay for. I figure even if I only get a few thousand miles out of the turbo I'll learn alot about what I want when and if I buy a "real" turbo. Maybe I'll even get lucky and it will last a while. I will start a thread about the turbo setup once it gets further underway. Still need an intercooler and injectors but if things go the way I want at work I should have the turbo on before winter.

Iv'e never used any in automotive applications but here at my work we have some epoxy that's rated to over 2500F.
I know Mcmaster has some rated higher but you need temperature to cure it properly