What I want to do is make some exhaust pipe flanges, weld the pipes to/in them, and have the flanges bolt to the manifolds and seal like headers do. What kinda material should be used for the gasket? Copperplate, aluminum flashing, welding blanket, oven mitt, asbestos shingles? The parts stores don't have anything (plus they probably all hate me), and I want to go riding tonight. What about High-temp silicone?
I get 12" x 28.5" sheets of exhaust gasket material at NAPA. #2499 (Fel Pro, "Pro Ramic"). It is perforated sheet metal between layers of composite material. It can be cut with sheet metal shears. I use a Dremel with a cutting disc for the small, tight areas. Permatex copper high temp spray works well when applied to both sides of your custom gaskets.
Undergroundss - when you use the Fel Pro exhaust material, do you still need a soft metal wrapped around either side? thanks.
I used something from Jeg's on the BBC lakester. It came in a sheet and you draw it out and cut it. I used the gasket making hole punches for the radiuses and hand sheears for the straight cuts. Looks like factory and it was a paper kind of material on the outside of a metal perforated core. Nice stuff. They have been on for 3 years and the material is great. We take the headers off a lot. We had no luck with premade gaskets that didn't fit right and always blew out where there wasn't enough support.
I did what you're planning to do to bolt my pipes to rams horn manifolds. I used Mr. Gasket header gasket material. Anyone that sells their header gaskets should have or be able to get it in sheets. Gary
I had a set of headers that I couldn't get to seal no matter what. One night I needed to get them back on and didn't have anything to use as sealer or gasket. So I "temporarily" installed them using 100% silicone bathtub caulk. Three years later when I sold the car the calk was still sealing the headers. It worked for me, your mileage may vary.
I have several cars with headers and I use RemFlex gaskets. http://catalog.remflex.com/ No retightening of bolts, great seal, long lasting. I hate replacing header flange gaskets, so I really don't care how much I have to pay to prevent the h***le of doing it over in a couple of years.
What wrong with a regular old doughnut gasket? They never leak or fail unless you ****emup or the bolts rot away? Or no gasket
You ever seen a V band clamp? I just used these on my 34's exhaust system. No gasket, perfect seal, easy removal and ***embly and takes up less room. Weld the machined ends to your pipes, slip on the clamp and tighten. The clamp pulls the two pieces together. I used them on my headers, mufflers and tail pipes.