I had removed the clecos (greased with Carnauba wax) holding the cooling duct in place while the resin was curing. I lightly sanded all glassed areas and evened out high spots on the in- and outside of the cowl.
Then I filled the holes with flox and resin and used the rest of the flox to fill the gap between the modified oil cooler mount and the lower cowl.
I also installed the oil cooler which I had left out during the main resin action as I didn't want to mess up the fine structure of the cooler with goopy resin.
It turned out that I should have installed it anyway (maybe with some additional protective blue tape) as the frame did not sit flush on the mount. My solution was to treat the front face of the frame with Carnauba wax and then mount the cooler onto a bed of RTV I had applied to the mount.
The idea is to let it cure and then carefully remove the frame and leaving an air-tight seal behind.
