fiberglass deck advice plz

heya,

i am currently restoring a shark cat, the current part of the project being replacing the deck, i have removed all of the original deck and about to start preparing a new deck to go in.

i am aware of the treating the ply etc for the new deck, and will be glassin over it with several layers, my question is though, the matting (or wateva the term) is not 'large' so there will be overlaps in it, as i have been led to believe to make a solid fibreglass deck you need to overlap the matting.

now to my thinking this will create an uneven deck as such, well thicker sections where the matting is overlayed, i have been told that there is supposebly a way of thinning the matting for the overlay sections to avoid this, and also been told just to lay it all and either sand it back to flat or use a filler as such to even out the surface again. but none of these people whom offered these suggestions i would trust to know what they are talking about

so any advice on how i am to over come this problem, or is it as simple as just not over lapping the matting

thankyou for any and all advice

 

You can do a much better job with cloth, staggering (if two plys) and overlapping the joints. A bit of sanding of the raised edge and a miniscule amount of fairing putty after, and two coats of neat epoxy, sand, then paint. Matt, IMO, is unsuitable for this, particularly since you are not going to use polyester.

 

Well you certainly wouldn't want to apply fiberglass mat over a plywood deck. I'm going to assume that you're going to use fiberglass cloth. Some people will suggest using heavy cloth (say 10 oz / sq yard). The thinking here, I believe is that the cloth imparts some strength to the deck. I disagree with this thinking. My thinking is that the cloth/epoxy combination adds some impact resistance but more importantly abrasion resistance to the deck. To give you an example of this I've used 6 oz cloth on my decks where they'll be walked on and 4 oz. cloth on the flybridge where they see little abuse. This is pretty light cloth but sufficient for my needs.

I can't understand why you want to use "several layers" of mat. This is just adding weight. Am I missing something here?

With the lighter cloths you can deal with the seams in two ways.

1. Seal your deck (all six sides and be especially fussy about the edges) with epoxy resin. I apply three coats.

2. Dry fit your cloth to the deck with a few inches of overlap. Don't try to get too precise with the overlaps. If you've never done a deck before, you'll find the cloth can slide around a bit as you are glassing it, so you need to have some margin for this.

3. I like to mark the seam lines with a black marker so I can see where the seam is once I get the glass down. Light fiberglass cloth is transparent once it's wet out with resin so this just makes things easier.

4. Apply the fiberglass cloth. I like to use a "slow" or "medium" speed hardener for this job so I can relax while I do this and not have to watch the clock. Use a foam roller suitable for epoxy and apply a thin coat of resin, enough to wet out the glass but not flooding the surface.

5. Once you get all of your glass down go clean up and grab a beer. But only one beer, you're not done yet. Get a sharp cutter ready, and a few pairs of latex gloves.

6. You should know about when your epoxy will kick off based on the temp and the speed of the hardener you've chosen. A little while before it kicks try lifting a corner in a hidden spot. You're timing is important here. You are looking for the point where the epoxy is no longer liquid, but is soft and plyable, before it actually hardens. WIth a slow hardener the epoxy will be in this so called "green" state for quite a while. The idea here is to work while the resin is plyable.

7. Using a razor knife, make a cut on the black line that you made previously to mark the seam. Cut through both layers of cloth. Now lift the cloth at the cut and remove the underlying piece of fiberglass cloth. Grab a new foam roller and some fresh resin to press the outer layer of cloth back down at the seam. Bingo, you'll have a nice seam with no double layer of cloth to fair out.

Timing is everything here. If you get called away, or distracted or drink to many beers this isn't going to work. The good news is that if you use lighter weight cloth as I do even if you end up wih a double layer at the seam it is not too difficult to sand it down fair. This is the second way to deal with the seam. With 6 oz. cloth you'll need very little fairing mix. With 4 oz practically none.

The more I think about it......skip the beer altogether until you're done. Make it iced tea instead.

The next day you can give her a second coat of resin to fill the weave. By applying the resin soon after the glass goes down you'll get a good chemical bond rather than a mechanical bond. Apply a third coat of resin if necessary. Sand down after a few days to a smooth surface apply a proper primer and paint. You're done!

Good Luck,

MIA

 

If I am reading your post right it did'nt say epoxy, I also am not familiar with a Shark Cat so maybee it is an epoxy boat ?

Any way to answer your question with mat fiberglass cloth (called CSM choped strand mat) rather than use the hard edges as it comes off the roll you take and tear the edge so THE FIBERS ARE LOOSE AND RANDOM but still in a striaght line. Think like the fingers on both your hands palms down and slightly spread tips pointing at each other then overlapping each other.
That is how you blend CSM with no seam.

Like others said however if you are using Epoxy then CSM is unwanted and just a waste of resin. Epoxy is definetly a better way to go sealing plywood.
BUT if you are using polyester then 2 layers of CSM on top and one on the bottom will work but may not last for long (or as long as epoxy resin , depends on how good you are) like a well done epoxy job