Waterproof Interior Pieces

[Twainer]

When waterproofing interior pieces such as seat cushions & side panels can you just coat the plywood in resin or do you need to put glass in it as well to keep the resin from cracking. I know pieces such as the floor & seat with no support need glass for strength but didn't know about decretive pieces.

 

[Woodonglass]

I use this...

(Click to pic to enlarge)

 

[mickyryan]

I have used polyurethane in the past to seal wood on swimming pool projects outside I have had it last many years in the elements . under a covering it should last longer then you or I still breath

 

[jbcurt00]

To answer your original question, fiberglass or no fiberglass, I must ask a question:

What resin? Polyester resin or epoxy resin?

For epoxy, you dont have to add the glass. Polyester resin must have glass where ever its used, or dont bother coating w polyester resin.

 

[Twainer]

To answer your original question, fiberglass or no fiberglass, I must ask a question:

What resin? Polyester resin or epoxy resin?

For epoxy, you dont have to add the glass. Polyester resin must have glass where ever its used, or dont bother coating w polyester resin.

On these particular items I have been using the cheaper Bondo Brand polyester resin from brick & mortar stores so it sounds like I should use a layer of glass along with it. Certain interior pieces that will not see much water I have been only coating them with a couple coats of exterior paint. One side of those will also be covered in vinyl as well. Thanks for everyone's input.

 

[Twainer]

I use this...

(Click to pic to enlarge)

Does thinning polyester resin with acetone have similar results as the above mentioned?
Right now I am dealing with the wood for the bow cushions. I have replaced nearly all of the wood on the interior parts but I would like to save these because they are already formed to the shape they need to be on the bow. They don't have to support anything but gives the vinyl something to wrap around. Since I already have plenty of resin & acetone I was wondering if a couple of thinned layers to soak into the old wood & then 1 layer of glass after that dries. If you don't think that would work well I can always go out & buy the items needed for the other formula.

 

[Woodonglass]

The trouble with using Poly resin without glass is...even though you thin it it will cure and when it does it gets very hard and when the wood flexes, and it will, the resin will crack and then water can and will get into the wood. The OTR formula is OIL based and remains flexible. If you use CSM with the resin it's a git better than the OTR but a bit more pricey and more tedious to do.

 

[Twainer]

I think for these particular items I am going to glass em' up. They are pretty weak. As I stated above the only reason why I want to re-use them is cause they are already formed to the bow curve.
Did I read somewhere where you stated it is NOT a good idea to use fiber glass cloth with poly resin unless you use CSM first? I may have done that with some seat cushions. I have been using up scraps leftover from the floor project. Been putting a layer of resign letting it soak in & get tacky. Then laying in the glass & wetting that in. After it dries lightly sanding then putting another thin layer of resign. Bad idea for things like seat cushions?

 

[Woodonglass]

Yup, anytime you use Poly resin you must use CSM before laying Fabric/cloth. The CSM has binders which are dissolved by the styrene in the Polyresin. This enables the resin to NOT break apart when cured and also enhances the bond with the following layer of Cloth fabric.