I use a heat gun. You need to heat the fiberglass until it becomes pliable, testing often. You also have to have a very good idea of exactly where you want it to go to. When it's reasonably pliable, bend to form. Here's an example of a pretty radical bend I did on the Mizar - it's towards the bottom of the page, with before and after shots:

Mizar cowl

As you can see, it didn't even ruin the paint, as it seems most paints under heat, seem to "flow" with the bend. Once it cools, it will retain the shape you made it. You can ease the pain, by wearing leather gloves. Depending on the time and care taken, you can make it very smooth....and thinner fiberglass takes to the technique easier/better than thick.

I don't remember ever reading about anyone doing it - I had to do some bubbles on a cowl once, and tried it. I have done it probably 4 or 5 times now, with excellent results.

DISCLAIMER!! I would try it first with a piece you have cut out of the cowl, to make sure it will work for you - I don't want to be responsible for someone ruining a cowl. BUT, that being said, I have never had any problem with doing it.

I even made a pine mold once, both female and male, for pushrod bubbles, heated the fiberglass, held the male underneath, and the female above, pressed together, and it came out "store bought"...much better than trying to glue on the bubbles that came with the kit.

If I can find the cutouts from the Giles, I will experiment, but they may be long-gone...

Roger