Originally Posted by
IRCantankerous
I have numerous planes with cowls, that eventually wind up with holes in the cowl oblonging and with screws that won't hold. I have tried putting CA hinge material under the cowl and the rubber backed washers. Velcro works in some situations, but distorts the cowl some. All hold for a little while but they also loosen up and either fall out or strip out. If some of you have ideas on the a better way please chime in and maybe some with pictures on what works for you. The best way so far for me has been with cowl rings attached to engine bulkhead, can't do that with all planes though.
Do it just as you describe . . . but, back out the screws and CA the holes to strengthen them. Then, before you put the screws back in (wait half an hour so the CA doesn't grab them) cut a 1/8" piece of glow fuel tubing and put it on the screw. This smushes out and makes a gasket that prevents vibration from opening the hole. I use the Futaba servo screws that have the flange around them and a shaft with out threads so it doesn't cut into the cowl. I make the firewall blocks out of maple or basswood.
The CA on hinge material is a good step as well.