Help with new boat deck fiberglass

fish4boats

Seaman
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Apr 26, 2016
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I'm putting a new deck in my boat. I'm using 3/4 pressure treated plywood. I want it to be right so what are some tips you can give me for doing the fiberglass as far as surface prep. Should the pressure treated be cured? Bonding agent to the plywood. Fiberglass weight minimum and max. Need to bond the boat sides to the deck also. Thanks guys
 

sphelps

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Nov 16, 2011
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Normally you should not use pressure treated plywood for the deck or anything that requires fiber glassing .. It would need to be dried out for many months before it's dry enough for a good bond ...Yes you will need to tab the edges to the sides of the hull and should glass the underside before it is installed ...
 

jackrabbit66

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Sep 26, 2014
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Pressure treated plywood has several problems. 1 the glue used in PT wood is not marine grade and will separate causing sagging and bulging problems, The wood uses is lower quality with lots of gaps and knots in it, it is usually super wet and the resin will not stick to it unless kiln dried. The only time you should use pressure treated is if your only going to pain the wood and replace it every 5 years or so or if your just going to cover it with carpet.

I'm currently re-doing my deck also. I originally though i would do pressure treated however Marine grade plywood isn't that expensive in coastal areas. I was able to find my 1/2" Plywood for $62 for 4'x8'. that's about twice what you'll pay for pressure treated, however, you only need 2-3 pieces of it to do a whole boat. The plywood is only a fraction of the cost of the whole project. Try cutting cost in other areas. Instead of using epoxy use polyester resin, buy your materials online to get a better deal than at west marine. Your already saving a bunch of money by doing it yourself, make sure you do it right and use marine grade plywood.
 

fish4boats

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There is not anywhere near me or remotely close to get marine grade plywood is the only issue
 

ondarvr

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PT can be used, but it needs to be dry, which can take a long time, also during the drying process it tends to warp, the glue used is fine, it's designed to be wet, strength isn't a big factor in this application so that's not an issue. I'm not saying PT is the best thing to use, only that it will work if used correctly. There is also PT designed for marine use, it's kiln dried and a better grade, it can be hard to find though.
 
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Woodonglass

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Dec 29, 2009
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You can also use any exterior grade plywood AC grade is the best. All ext. Grade plywood is made with 100% waterproof Glue, just like Marine Grade. The main difference is the Quality of the Wood Plys and then type of wood used. Marine Grade has very few voids in the plys. AC grade will have a few but not to bad. If you use Thickened resin to fill the voids in the edges and on the flats it's perfectly acceptable to use it for your boat deck. Some of the Big Box stores carry the Aracuo Brand of plywood and it's excellent for this purpose. About 1/2 the price of MG.
 

fish4boats

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Apr 26, 2016
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Well I'm curious as to the process of prep for the installation of the fiberglass. 6 months cute time for pt. I'm a contractor so this I know. I'm looking art using a 17 oz cloth and a premium resign that us marine grade. I'm also thinking about building a live well. In the front bow. My friends have a kiln but I think the lumber will turn to garbage if I do that. I only have 53" wide to cover. There is about three hull bands that run across the 53... I found a spot that has mg plywood it's about an hour and a half away maybe two. I think I'm going to get some later this week. I need to move fast with this because it's my walleye boat and the season is in lol
 

JASinIL2006

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Feb 10, 2012
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I wouldn't use PT and I'd think twice about MG, too. Woodonglass is correct: exterior grade plywood is fine. Auraco is a high quality exterior grade plywood for a fraction of what marine grade will cost.
 

Woodonglass

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Dec 29, 2009
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If you use Polyester Resin, you MUST use Chopped strand Mat as your first layer prior to layingthe 17oz fabric. If you don't the fabric WILL delaminate from the wood! 17oz fabric for your deck is WAY to heavy IMHO. 6oz is plenty strong. Lay down a layer of 1.5oz CSM and then a layer of 6oz Fabric and a final layer of 1.5oz CSM and you'll be good to go. This should be a good read for you...Fabricating Decks, Stringers, and Transoms
 
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