Matte vs. cloth

[slowpoke]

So the other day I saw a roll of fiberglass matte in the back of one of the work trucks, and I was naturally curious about what they used it for. It seems they use it to seal the decks of balconies. This isn't your standard marine fiberglass mat, it's much thinner(and lighter), and I was curious how much it cost, and how well it would work in place of cloth.
Come to find out, this stuff comes in a 50" x 100ft. roll, for about 40 bucks. It would probably be too rough for the bottom and sides of the boat, but I'm thinking decks and cabin top for sure. Any comments? Suggestions on how to keep the resin from building up? Anyone ever try using mat and peel ply?

[Chad]

It has a different binder than the matts used with epoxy or polyester resins. The shops that sell it say "NOT for laminating".
I'd steer clear of matt anyway. You can get 6 oz cloth for about $6/yd, and you won't be fighting the loose fibers. I'd look at C&J Composites website or their eBay store for occasional stuff around $5/yd (and have a look at Raka's website for their 9oz biax tapes. I don't think you want to cut your own tape- it's laborious and the results are hard to keep from being messy.)

I've used chopped strand matt a little on other projects and it can be fun- it goes all limp and moldable when wet out. Ive used peel ply and plastic sheet to get a better finish, but those only work on pretty flat or non-compound curves. I think you'll be fighting the stuff to get a good result, all out of proportion to any slight material cost saving.

You can get nice results with just glass cloth at 5-ish/yd, versus csm at 5/yd AND peel ply at a couple more/yd. And a bunch more sandpaper and epoxy and filler to get to look right...

[Kevin]

I agree with Chad. I'd steer clear of chop strand mat for our purposes. It's the stuff they use below the cloth to build up bulk in old school typical boat hull construction. Your typical 35 foot boat has literally a ton of the stuff. They typically would lay down a layer of very light cloth referred to as veil and then layers of chop strand mat on top of that. The veil is there to stop print through of the rougher lower layers in the lamination.

Now if you ask nice I'd consider selling you the tail of my roll of e-glass that I purchased moons ago. It's 6oz x 60 and I'd guess that there is at least 20 yards still on the roll. I can only guess on the length because I pulled off a 30yd piece for Ron and Jon and then used what I needed for my boat which was probably more than 30yd by the time I was done.

Kevin.

[Chad]

Oh, and another thought:
Glass is cheaper per ounce than epoxy. CSM is always going to be a resin-rich layup, so it'll cost more in epoxy, too.

[micah202]

..........as above ,,the binder in FG matt becomes a milky GOO when used with epoxy,,so it can only be used with polyester resin,,,which would be a big bonding mistake on plywood,,especially if the plywood has -ever- gotten wet

..in terms of kevin's offer on cloth,,,dealers usually sell and measure a roll by weight--this will help you estimate how much remains on the roll

[slowpoke]

Thanks guys,
It was just a thought, and the price was really tempting. I think Chad's comment hits home, in that CSM takes a LOT of resin. Not only cost, but weight issues. I didn't know that about the binder turning into goo- if the decking mat uses a different binder, I wonder if it would do the same? How much you want for the cloth Kevin? Could you PM or mail me with a Price? Thanks
p.s. Include shipping cost!

[Kevin]

Rocky, message sent your way regarding my tail end roll.

Kevin.

[slowpoke]

Got your message, sent you a reply, Thanks Kevin!