
I have to cut an elliptical hole in the stern of our boat to accommodate the heater exhaust fitting above. And just to add to the fun and games, I need to also make two high-temperature gaskets out of silicon sheet.
So how the heck do I get a nice clean hole just the right shape in both the transom and the gasket material?
My first inclination was to use a hole saw to cut a hole in the transom the same as the minor axis of the ellipse and then start shaping with a Dremel and burr bit. I guess that might have worked, but I’m not either the neatest or the most patient guy around, so it also could have gone very wrong.
And what about the gaskets?
Time to work smarter: