can i fibreglass resin over plywood??????

Hi all, its been a long time on this site but i know, i will get some good answers. Right, i am building a teardrop trailer (a teardrop trailer is basiclly a tent on wheels, google it and one shall see) I am making the sides, bottom and top skins out of plywood. I want to make the whole structure waterproof, body filler the whole structure and spray it to get a nice finish. I am undecided on wether to use fibreglass matting or not. A friend has told me to use strips of fibreglass on the edges were the joins are and just resin the rest of the structure prior to body filler'ing ,sanding smooth and spraying. My question is can one resin over plywood or do i have to put anything on the plywood prior to applying resin? also as it would be expensive to fibreglass mat the whole structure as it is 9 foot long by 5 foot high and wide, would it be more wiser to firberglass mat the whole thing? my friend seems to think I am throwing money away as he said the resin would be strong enough on the surface of the plywood and by putting mat strips on the joins of the edges would be good enough Any comments on this???? Thanks Ian

resin on the ply, matting on the joins, just like a mirror dinghy

Thanks for the reply john, so i dont need to apply anything to the plywood prior to putting the resin on? also, when the resin dries is it totally waterproof? sorry if the questions are a bit dumb but i am new to fibreglass and i am eager to learn. One last thing, will i just need to put one layer over the edges of the joining wood? i know you can buy different thicknesses of matting, and the reason i am asking is that when i body filler it sand it and then spray it i dont want any cracks appearing due to the wood swelling and contracting. Ian

the ply needs to be clean dry, free from grease ect.

You can get drums of the stuff from roofing places alot cheaper than anywhere else i have found.

GRP is a composite material. It is the glass that gives it its strength and the resin serves to give rigidity and form. Applied to the ply wood the resin will give the waterproof property you require and the ply will give all the strength. Epoxy resins are better than polyester but this is reflected in their price. Can you post a pic of your finished teardrop? The resins also have different water resistent properties, for this reason epoxy is best.

Polyester is cheaper and easier to use.You may need two coats on ply..the first will soak in pretty quickly.
If you are using body filler on any of it best to put a layer of mat over it and sand down when cured.Then a flow coat of resin on top.450 gm mat will be thick enough for this job.
If you get your materials from A GRP supplier get brushes and rollers from there too.You can use those from a DIY store but they may be melted by the resin or acetone if you use it as a cleaner.
Most polyesters have a tacky surface when cured...If on your final coat you add some liquid car wax to the mix that will be overcome.(Just a thimbleful to a pint)
Quite a few manufacturers of GRP products in your area...many will supply you with materials...BUT TAKE YOUR OWN CONTAINERS.

any chance of some pics of the tear drop?? Im very interested

I'd go with the GRP gel coating idea, I did may garage roof with it. It's grand stuff.