Sealing Holes In A Balsa Cored Deck

[jimking]

Can someone please advise on the best way to seal non-load bearing holes through a balsa cored deck, ie for a cable to pass through or a deck vent. I have read that you should use epoxy paint, by this do they mean something like Gelshield 200? Any advice would be appreciated but please make it simple.

Regards

Jim King

 

[bigwow]

I seal mine with epoxy resin thickened with mico fibres.

 

[boatmike]

Anything that is waterproof and adhesive will theoretically work. The ideal however if the hole is big enough is to use something like West System Epoxy that is easy to obtain. When you have "painted" around the inside of the hole with this and it has cured it is a good plan if its something small like a cable hole, to inset a small GRP or UPVC tube in the hole and seal it in with Sikaflex. Belt and braces perhaps but you really don't want water in the core. You can then use a surface cable gland or even just seal around the cable with silicon to stop water ingress. Silicon will break away easily if you need to change the cable. Sikaflex wont. Bigger holes for deck vents etc it's still a good plan to paint around with epoxy before sealing the vent in place with Sikaflex. Its also good to not do the screw fittings up tight until the Sika has cures to avoid squeezing it all out.

 

[webcraft]

I believe the recommended method is to drill the hole out oversize, fill it with GRP (mat/resin) or epoxy, whatever is the most convenient, then redrill the hole through the middle of the filled area. This guarantees water won't seep into the core.

- W

 

[Gordonmc]

I suggest going a step further and creating a void in the balsa between the glass skins and filling with epoxy and micro-fibres.
Use an allen key in an electric drill to rip out a centimetre or so of balsa all round, fill and then drill out the hole again. It will stop the top skin compressing and eliminate the risk of wet finding its way into the balsa. The fixing screws for the gland or whatever will have a better seating.

 

[Gordonmc]

Snap!

 

[rogerdog]

I would go with Gordonmc's advice you can't be too careful - and prevents compression that is an issue with cored structures having fittings bolted through etc. If water and then rot get into the balsa core the repair is horrific !!

Prevention is better then cure and all that