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Even the best fiberglass and epoxy will suffer under certain conditions. Boat builders routinely test their mixes at varying temperatures and salinity levels. For the best knowledge for your use case, you will want to test the same kind of board under conditions designed to accelerate the deterioration of your part. 

 > "Only exhaustive testing on finished parts can determine suitability for a particular application" 

(I think that's from IP's Machinery Handbook, but I can't seem to find the quote right now.)

![PCB](https://electrical.codidact.com/uploads/hvm1nh6zrk9c8sh3dz3c2zwzfso8)

The circumference of your board (where it is cut into a circular shape in your picture) is a weak point: whatever coating you use (solder mask, epoxy resin, etc.) will likely begin delaminating at the edge between the face and the side, because the cut leaves a sharp edge, which produces a thinner coating right on the edge--coincidentally the same place where it will be more likely to be exposed to abrasion or exposed to other stresses and eventual damage. Then, since the ends of the fibers are exposed, the boards internal structure itself will be at risk of further delamination, since it is easier for water to "wick" into the  board from the ends of the fiber than from the sides, rather like a wooden fence post sucks up water through its ends more than its sides. The bolt holes will be at a similar risk, but to a lesser degree.

You can improve this weak point by adding a structural bolt ring, or by giving special care to the protective coating by rounding the edges and sealing the edge of the board properly.

Another factor to consider will be varying pressure _inside_ of your finished part, for example if it were a small capsule with some air inside; the pressure will vary with the temperature, causing flexing in the board which will also accelerate eventual structural failure. Not to poke fun at disasters, but "Remember the Titan!".