For a one off cowl the easiest way to go is to make the plug out of blue or pink 1'' insulation foam. Once you get the sape you want you simply cover the plug with low temp iron on covering or even mylar packing tape. Once covered you would wax with a good carnuba wax and then apply 3 layers of 3 to 4 oz cloth and epoxy resin over the structure. When cured you can sand the exterior smooth and pop free from the plug depending on the shape you may need to seperate into 2 halfs and then re-join. Whole process can be done in a weekend.
Thank you this sounds like the way to go and I have the foam board in 1" and 2". Can that be covered with standard boat type resin or will the heat attack it, ? I even have the wax and the cowl shape will be such that a plug will not hang up if it comes lose, then I could dig it out if it hangs up. Whats this stuff some pour on the foam that desolves it ?
I'm really getting an education just building a cowl, the mould making aspects of it are way over my head so thats out. I simply don't know the first thing about any of this compatability with the stuff used to do this. I can build a very nice plane thow.
Thank you for your help, Leroy