Making a gasket for custom exhaust flange(s)

[mangocrazy]

Some years ago I took the plunge (so to speak) and cut the 4 pipe section of my CSC/Ansa exhaust into two parts and had a local engineering firm fabricate flanges which were welded onto the cut pipes. I've attached photos of the modification below. That gave me the headache of how to seal those flanges, which I only partly solved by the use of exhaust paste. Frankly, I'm not a fan as it's awkward to apply and doesn't really seem to work that well anyway.

So I turned to eBay (as usual) and started searching for exhaust gasket material. I bought some chunky looking metallised gasket sheet but found that it's almost impossible to cut into any kind of accurate shape. It's very, very tough and is beyond the scope of tools I have at my disposal. I've made a reasonably accurate template out of cardboard to work from, but I think I need a more compliant and workable material to transfer it to. The 7mm punch I have that easily cut out the bolt holes in the cardboard template just makes a little dent in the gasket material.

So does anyone know of a gasket material that will withstand exhaust temperatures, but is also workable with readily available hand and/or power tools? That joint definitely needs a gasket, and due to the one-off nature of the flange, I will have to make it myself, it seems.

[mangocrazy]

Just a thought - would high temperature RTV (i.e. silicone sealant) do the job?

[peteracs]

Hi Graham

Plasma or modern bench cutter they use for metal. I am sure there must someone local who has one?

Peter

[WestonE]

Hi Graham

Copper sheet is your friend here. It is soft enough to compress correctly with a light buttering with Exhaust paste. Even better you can cut it with a Tank cutter/conventional drill with a light Dremel clean up. My Montecarlo exhaust had copper gasket joints made by the exhaust fabricator.

Enjoy.

Eric   

[mangocrazy]

Hi Graham

Copper sheet is your friend here. It is soft enough to compress correctly with a light buttering with Exhaust paste. Even better you can cut it with a Tank cutter/conventional drill with a light Dremel clean up. My Montecarlo exhaust had copper gasket joints made by the exhaust fabricator.

Enjoy.

Eric   

Thanks Eric. When Googling 'exhaust gasket material' copper came up a lot and as you say is soft enough to deform as required. I might also have a word with the engineering firm who did the flange conversion and see if there is anyone local who could fab up a gasket.

Graham

[mangocrazy]

The engineering firm I use a lot have pointed me in the direction of ESP laser cutting (www.esplaser.com) in Rotherham. They've taken my exhaust manifold and cardboard template and will send me a quote by email. It sounds like I should get around 3 copper gaskets made out of 1.5mm sheet for their minimum order charge (£50 + VAT) , which I'm very happy with.

Graham

[peteracs]

Hi Graham

Good result, you will not need to have any more made after that I suspect.

Peter

[mangocrazy]

Peter,

The final quote came in at approximately double the original verbal one, but it's still what I'd regard as reasonable for a complete one off (or 3 off, to be precise). I can't imagine I'd ever need more than three, and I'm fairly sure they can be re-used to a degree, especially if they are annealed befrore being re-used.

Graham