Page 1 of 1

xf glassing question

Posted: Tue Nov 17, 2015 9:48 pm
by rtboating
i was going to use 1708 glass on the bottom of the hull and was wondering how many layers to put. i was told to go with 3 but not sure. any info on what prev builds used would be useful

Re: xf glassing question

Posted: Wed Nov 18, 2015 9:57 am
by jacquesmm
3 is way too much. Trust the designer (that's me), one layer each side is more than enough.

Re: xf glassing question

Posted: Wed Nov 18, 2015 5:35 pm
by rtboating
o ok i was just told that by someone who has build more then 10 of these. it seemed a little much but thank you for the info

Re: xf glassing question

Posted: Sun Nov 29, 2015 10:37 pm
by rtboating
1 more question when playing this 1708 layer on the bottom of the hull im assuming the chopped mat side goes down and the biaxial is up? figured id ask before jumping into it with the wrong idea

Re: xf glassing question

Posted: Mon Nov 30, 2015 4:32 am
by Woods Designs
It would be chop side down. But if you are using epoxy then you don't want to use a csm backed fabric. That is really only suitable for polyester resin.

The csm helps bond biaxial glass layers together when using polyester as that is a resin not a glue. Two layers of biax glass + epoxy will stick really well. The binder used in csm is usually not compatible with epoxy as it needs styrene to dissolve. And csm uses more than 2 times the amount of resin to wet out, so is heaver and of course more expensive

The only way csm is really useful is that it helps stabilize the fabric if the biax is very loosely stitched together

I'm sure Jacques will comment if I am wrong

Richard Woods

Re: xf glassing question

Posted: Mon Nov 30, 2015 3:38 pm
by jacquesmm
We very rarely use stitch mat like the 1708 for the reasons Richard explains.
We make some exceptions when we want to build a thick laminate fast and don't need more strength than what is already there.
The XF20 is one of those exceptions.
The XF20 bottom is very strong to start with but we want extra thickness not only for stiffness but also for resistance to abrasion.
Most 1708's have a binder for polyester that will not dissolve in epoxy but we sell an epoxy compatible 1708.

If you do not buy 1708 from BoatBuilderCentral.com, be absolutely certain that it is compatible with epoxy.

I don't know of any mat (pure mat, not stitch mat) that is compatible with epoxy.

Mat side down.

Re: xf glassing question

Posted: Mon Dec 07, 2015 2:43 pm
by rtboating
http://boatbuildercentral.com/proddetai ... _bias_1708 so this will be epoxy compatible? ill plaec an order of some when i get home if it is

Re: xf glassing question

Posted: Mon Dec 07, 2015 3:04 pm
by jacquesmm
Yes, all the fiberglass we sell is compatible with epoxy.

Re: xf glassing question

Posted: Mon Dec 07, 2015 7:14 pm
by rtboating
thank you. i just placed my order. how many gallons of epoxy should it take to get the outside of the hull glassed?