how to build a thick fiberglass laminate using epoxy resin??

[albergsailor]

The largest standard cloth i found is only 12 ounce. It takes a ton of those to make even 1/2 inch of thickness. With polyestor achieving a thick laminate is so simple with mat and woven roving. But mat isnt really supposed to be used with epoxy right?, and without mat you cant use woven roving right? so to build a thick laminate with epoxy you use 20 layers of 12ounce cloth? That cant be right. Or is that the only way to build up epoxy? Or does one just try and find epoxy compatible mat.. google has been no help in this one..

[neilpride]

I use West with mat and woven with no problem at all, the problem is some glass supliers sold real crap out there, some people have a hard time with mat and epoxy , my trick is to lay the epoxy in a plastic surface , put the piece of glass over , and pour some epoxy in the top , wait few seconds and you see the glass tourning cloudy, time to roll the epoxy evenly, Poly is more thiner thats why wet out glass better, same for woven , try to found a thin specific epoxy for laminate, some epoxys are a thicker and some thiner, thicker good for mixing fillers, thiners good for laminated, how thick you want to make it? in the old days a laminate is one layer of mat and one layer of woven , could be to get a 1 inch thick laminated you need probably 9 to 10 laminates, but im not sure,, depend of the glass specs....

[colemj]

Mat has a filler that dissolves in polyester, but not epoxy. You can use it with epoxy, but it is much more difficult to wet out properly. It wets easily with polyester because the filler dissolves, not because the poly is thinner.

There is epoxy-specific mat made with fillers that do dissolve in epoxy, but you will need to search for them specifically.

If you go with biaxial or triaxial cloth, you will find much thicker versions and have a much stronger laminate than cloth. You won't need as much thickness for the same strength.

What are you glassing? Polyester may be just fine and less expensive for your needs.

Mark

[albergsailor]

I know all about the binder... And i know about biaxle. I swapped out my 1700 and another lighter weight roll of it to go with normal standard cloth. That biaxle is a royal pain to use. It falls apart, is very hard to wet out, i didnt even try wetting the 1700 but im sure it would have been a pain and used alot of resin and time. So apparently biaxle is pretty much the only option to build thicker layers. who knew trying to fix large holes with epoxy would be such a pita. i have a hole i can fit thru but i fixed that yesterday using many layers of normal cloth and epoxy. it does seem really strong but its still thinner than the origonal laminate... and i was wonderin, is a laminate made of woven roving/mat equal in strength to one made of nothing but 10 ounce cloth when both lamiates are the same thickness? the other hole is in the front of the boat and will take many layers to get the desired thickness. this whole entire process would have been 10 times easier with polyestor laminating resin. i wish i would have known ahead of time. unless someone can convince me otherwise i think the rest of the project will be usin mostly polyestor.

[albergsailor]

guess i was right in my thinking. 10ounce cloth is stronger than the same weight woven roving... great for making repairs which is great cuz now i can use epoxy with peace of mind

[colemj]

Was the biaxial stitched? I've always found it easy to wet out and never had a problem with it falling apart - the stitching takes care of that. Wet out is a function of thickness - you can't have 17oz glass that wets out like 10oz.

You haven't exactly said what you are doing, but polyester is fine for almost all jobs. Probably secondary tabbing of wood to old glass would be one of the jobs for epoxy. If you are fixing a hole you can fit through by spanning with glass cloth, you may be better off making a piece on a table and then glassing that into the hull. I wouldn't have a problem with polyester in that job.

Mark

[motion30]

have you considered vinylester. superior to polyester. but perhaps easier to work with an epoxy

[albergsailor]

the biaxle had a piece of string holding it together which didnt do a very good job. i could have used it but it just seemed more of a pita to wet out and it would easily seperate