Hi there Gary
Okay then we will try this one
How important is it to get your hull inside the house to dry out? EXTREMELY IMPORTANT!!!
The reason for this is, when the wood absorbs the timber it naturally swells slightly – so, at the state your hull is at the present time, sitting outside – the planks will all naturally be swollen. You have found the evidence, where the glue is turning white, that is a sure indication of:
a) Dampness in the air
b) Freezing temperatures/or temperatures very low
You have temporarily cured this by using a hair dryer and the heat has dried the glue out, but, it hasn’t removed the dampness from the timber. So, if we ignore the dampness in the timber and we carry on and seal the hull with a fibreglass layer (on either side of the Planking) you have in actual fact trapped the dampness inside the timber. So, as the hull warms up, with the outside temperatures warming up, this moisture will try to leave the timber. The moisture will find it a lot easier to pass through the timber than it would find it to pass through the polyester resin – so that it becomes trapped between the polyester resin, gradually soaking into the polyester resin over a period of time; and therefore breaking the bond between the timber and the resin. You will find areas where the timber will rot underneath the resin and the resin will turn to mush. This is not to be confused with OSMOSIS – although it has very similar symptoms. So, this is why it is essential that we remove as much dampness out of the timber as possible. The next thing we have to tackle is that you have used a 2mm thick veneer on the hull in places. - Ideally, it would be preferable to remove these and replace them with either planking/individual planks – but rather than trying to remove them and destroy part of the hull LEAVE THEM IN PLACE but when the time comes to either plank over the top of them diagonally, or glass over the top; we must ‘rough’ the surface up really well – use a Stanley knife blade so you deep marks into them NOT ALL THE WAY THROUGH THOUGH this will allow the glue or glass fibre resin to have a very good key on these pieces of wood.
FIBRE GLASS RESIN
You have obviously worked out the amount of matting you require to cover your hull; the calculate the amount of resin you will require – you need to know the exact weight of all of your matting combined, say, for arguments sake the total weight of matting you are going to use in your hull was say 2½ lb – the amount of resin required for that would be 5 lb of resin in weight – i.e. for every lb of matting – you need 2 lb of resin – or, 2½ lb - .
DIAGONALLY PLANK THE HULL
I would suggest 0.8 mm thick plywood – by about 12 mm wide strips – cut across grain. In other words, the outside grain of the plywood goes across the width of the plank; not along the length. This is because you will find cutting this way, it gives the plywood a lot more flexibility for bending around curves.
Even if you do diagonally plank the outside which WILL increase the strength, you will still have to re-enforce the inside with fibre glass matting and resin – but, you would be able to use either 2-3 coats of resin with tissue matt on the outside or a couple of coats of resin on the outside to finish your hull off. The only thing is with diagonal planking on the outside, is that you have to be precise in laying the planks and avoid any gaps between the planks.
Hope this is of some help and has given you some more food for thought.
Aye
John e
Bluebird.