This quote was taken from another thread, so as not to take that thread off topic.I think the gasket idea needs further thought.
I am in the process of replacing the dead lights on my Scampi. I could put back the existing ones with new beding, but I am leaning toward replacing them entirely with 3/8 acrylic, smoked, for a nicer look. Not only will it make the look newer, it will cover some gel coat stress cracks that are around the edge of the frame.
This topic has been discussed quite a bit here, and I have taken some advice from various threads. I am planning to over size the holes the bolts go through to leave room for expansion and contraction of the plastic, use stainless barrel nuts, countersink the holes to make room for sealent, and probably use 3M 101 under the bolt head.
There is one thing I have not decided, and that is weather to use sealant or a gasket between the plastic dead light and the fiberglass.
I am leaning toward a gasket for these reasons:
Its easier to replace when it dies, as there will be no mess to clean.
There is evidence of silicon having been used to bed these dead lights in the past and I won't have to worry if an adhesive will adhere to the fiberglass.
if I use bolts every few inches, then that should be sufficient to produce a strong mechanical bond so i won't need an adhesive.
I won't have to worry about sealant (3M 101, butyl, whatever) not sealing so well around the shafts of the barrel nuts, although the same issue may exist with a gasket as well.
The disadvantages of a gasket are:
May not last as long as a good sealant.
I will have to fill in a number of large gel coat chips around the edge of the opening, to make sure there is a tight seal all around. Sealant would probably fill this easily.
I would appreciate any thoughts...