Drilling a hole in fibreglass for a solar panel question.

[Anakin]

After idling away viewing boat forums, trying to see what the consensus is on holes in fibreglass, it seems that most people assume that the glass fibres have been fully saturated with resin when the hull/poptop was made. Hence, no need to coat the cut edges as any water vapour should stop at the first hint of resin. But, absolutely use sealant around the cable/porthole/deck winch that has been attached.

 

[Skyliner33]

To seal the cut edge of a fibreglass panel you can use Cyanoacrylate adhesive more commonly known as Superglue.
This is a recognised process in aircraft engineering repairs.
You just smear the glue round the edge and it seals the fibreglass stopping water wicking up the strands as @oldiebut goodie has already indicated.

I'm sure I would end up superglueing my fingers to the fibreglass

 

[oldiebut goodie]

After idling away viewing boat forums, trying to see what the consensus is on holes in fibreglass, it seems that most people assume that the glass fibres have been fully saturated with resin when the hull/poptop was made. Hence, no need to coat the cut edges as any water vapour should stop at the first hint of resin. But, absolutely use sealant around the cable/porthole/deck winch that has been attached.

Once the fibreglass has been cut the fibres are no longer fully encapsulated as they were when laid up originally hence the need to seal.

 

[Anakin]

Once the fibreglass has been cut the fibres are no longer fully encapsulated as they were when laid up originally hence the need to seal.

I may have this wrong, but what I read says that, yes, there are “naked” fibres at the cut site, but they are only millimetres long and as soon as you go any deeper the fibres are encapsulated again. Hence water can at best, just wet the tiny area surrounding the hole.

Anyway, I learned a new tip about superglue today and I’ll seal the hole when I drill mine, out of an abundance of caution.

 

[oldiebut goodie]

I don't know how you lay up fibreglass or what with but usual mat is not just millimetres, here is a random sample. ( mainly 50 - 100mm strands )
I suggest that you do a little less reading and carry out practical laying up before saying that. If the glass were only millimetres there would be no strength in the structure.

 

[airhoguk]

Oldie but goodie is absolutely correct. When you cut the fibreglass you have raw edges, this will allow moisture to wick into the fibres along the whole length of the individual fibre. When the fibres swell it causes delamination of the fibres and then forces the encapsulated fibres apart. The fibres no longer encapsulated can then absorb more moisture and hence the delamination continues. The moisture can then cause the resin to break down as well causing blisters underneath the surface which then need to be popped and everything thoroughly washed out as the liquid is very acidic. It’s called osmosis and unfortunately doesn’t matter how well you lay up the fibres it will happen.