Monday, 10 September 2012

Preparation is key before glass sheathing a deck

The paint has been stripped from the top sides. Note the gap between deck and plank that will need to be filled with epoxy as will the screw holes.

Finally I am almost ready to glass sheath Zephon's deck. Rae and I are planning on sheathing the deck on Saturday. In the meantime there is still a lot to be done, preparation is key to ensuring that the deck lasts for the next 25 years.

The deck has been stabilized (any deck planks that moved have been re-fastened) the deck has been belt sanded diagonally to make it as fair as possible (the deck planks have cupped over the years and obviously this cupping had to be got rid of before laying the plywood).  Once the deck was faired it was then primed using metalic pink primer. Patterns were made using strips of cheap 3mm plywood. The strips were laid and cut to fit, scribing as necessary. The patterns were held together by staples, a glue gun would be a good alternative. The patterns were laid on the plywood panels, secured in place and carefully drawn around before being cut-out using a jigsaw.  The back face and edges of the panels have been sanded with 80 grit prior to being given a coat of epoxy before being bedded in position on roofing felt adhesive tar.

The plywood I am using is good quality 6mm marine ply. This plywood is Lloyds approved and it should last 25 years. The plywood panels have been fastened with size 8 silicon bronze 3/4" grip fast nails. The edges of the ply have been fastened using size 6 silicon bronze 3/4" counter sunk wood screws. This should prevent any movement in the ply and hold it tight to the deck substructure. This is very important as excessive movement will cause the epoxy to crack and allow water ingress which would be very disappointing in the extreme.  
This seam has been raked out ready for splining. 

The deck after belt sanding.

Blocking pieces on the port side.

Starboard side blocking pieces. 

Deck primed and pattern making about to commence.

Plywood panels in position.

Plywood panels after having a coat of epoxy to seal them.

Fastening the plywood in position.

The bedding compound: Roofing felt adhesive tar.

Note the slight plywood overhang round the edges. This will be trimmed fair.

The deck prisms have been counter sunk into the ply. These prisms will obviously be removed when sheathing the deck.