What ply for cast deck?

[Castaway]

I am planning on making a front cast deck for my 4.2 Quintrex dory. What type of ply do I need to use; marine ply or can I get away with external ply?

It will have carpet over the top but do I have to coat it with anything to seal it?

Thanks for any advice you can offer.

Mike ;D

[Ally Jack]

Castaway,

I used 16/17mm external ply for my casting deck and I sealed it with a 2pac wattyl product. I can't remember the name of it, but it's alot like fiberglass resin.

I glued carpet over the top of that and have had no problems with it lifting.

Marine ply costs heaps more and it has to be sealed as well, so save your money

Ally Jack

[Castaway]

Thanks for the info Ally Jack. That will give me something to do over the Christmas holidays.

Mike @ Castaway

[QuinnyDory]

Hi Castaway, I used approx 17mm external ply when i did one in my 460 dory. I coated it in undertile waterproofing I had left over - made sure to seal the ends well. I carpetted over that. Have done this in a few tinnies now and it seems to last for years.
cheers

[FNQCairns]

I have the same job coming up soon but mainly for extra storage and it will double as a casting deck, I will use either CD grade ply or form ply which is the same thing but has a phenolic coating so I will only need to seal the sides to get fair service from it. The CD grade uses the identical glue marine ply uses as does the form ply.

cheers fnq

[STUIE63]

Mike dingo hire on Ingham road were selling second grade form ply for $42 nothing really wrong with it just had a chip out in the corner or something the other week . I had this in a tinny as a floor and lasted years and is still going tinny lives outside in the rain
Stuie

[Scott nthQld]

definately use a CD external ply with a marine varnish to seal, For ply is good too but a bit more exxy and glue for your carpet doesn't take too well. Marine ply is not what it used to be, as often you will find it is just normal cd ply with a hardwood veneer over the top, only they charge you twice as much (or more in some cases), where as it used to be 100% hardwood (usually maple)

As for size, I don't know wheher you will need to go as heavy as 17mm, it depends on the bearers, and how much support you will have underneath. You could co as light as 12mm if the spacing is close enough (no more than 350mm), which will cut the cost in half again.

[Marlin_Mike]

Coming from the building game, i would recommend 12mm or 17mm good one side formply.

Mike

[plaztix]

It also helps if you apply some lanolin grease to the end grain after filling it with which ever sealer you decide on. Most sealers will require about 5 coats before they start to fully seal the ends and a liberal coat of lanolin helps as this is where most rot will start.

This is no good though if you need to stick the carpet to the end grain as it will not stick to the lanolin grease, it only works if you are wrapping the carpet around to the underside and glueing and stapling there.