Having read a fair bit on the subject, this is how I expected the deck to be constructed. The deck filler is completely encapsulated in resin and the headliner batten is mounted below this. I figured out that my hatch is screwed down with self-tappers.
This is what I found - only a lot less tidy. The deck filler is not sealed and is contiguous with the headliner batten. One major issue is that the wooden parts have lots of voids and these are going to cause problems with making-good.
The diagram is a little idealised but here's the main features:
Remove old hatch
- Old hatch in-situ.
- This job will go over a few weeks so a tarp will be used to protect the area and keep the rain out.
- Unscrew hatch.
- Clean and remove loose gelcoat / resin.
- Over-fill with polyester resin.
- Sand down to a smooth finish to blend with gelcoat.
An epoxy plug is created for each screw. This supports a screw / bolt and also lowers any possible leaks below the deck filler.
- From above, drill a hole about double the diameter of the screw.
- From below, using a spade drill, drill out a wide-diameter hole to contain a plug of resin.
- Cut and epoxy in short pieces of hose (green in the diagram). This is to contain the epoxy plug and stops the glue leaking away into large voids.
- Hose glued in place.
- Temporarily plug the bottom of the shaft with candle wax and tape it in place. This is to contain the epoxy resin and sets the lower limit of the plug.
- Through the top hole, pour in a weak epoxy mix (pink) until the plug is full. Do this in 2 or 3 stages to stop the plug from over-heating (exothermic reaction).
- When the epoxy has set hard, remove the wax to expose the bottom of the plug.
- Mark and drill out the plugs for the screws.
The new hatch frame, unlike the old one, extends below the deck level. A recess needs to be cut into the existing cutout and, as this, in parts, encroaches into voids in the deck, needs to be made good with epoxy.
- After marking out, cut a recess with various Dremel tools about 1mm oversize all round. Tidy up any sections that break into voids in the deck ready for epoxy glue.
- Use a stiff epoxy glue to fill any gaps and to smooth down rough parts.
The frame is bedded in Sikaflex 921 and through-bolted.
- Loosely screw the frame in position and mark the limits of the Sikaflex on the deck and frame.
- Dry-fit from topside.
- Blue-tape the frame and deck to mask Sikaflex.
- Clean contacting surfaces with acetone.
- Coat mating surfaces with Sikaflex.
- Fit frame and snug up the screws.
- Wipe off excess Sikaflex and remove tape.
- Leave overnight for Sikaflex to set.
- Fit opener and tighten screws.
- Finished job.
No comments:
Post a Comment