which resin for fiberglass hull repair

[pcrussell50]

fortunately, both of my fiberglass hulls are intact, but i like to have a strategy in place in advance of a repair. i'm pretty comfy with working with fiberglass in general, from repairing my surfboards over the years. my surboards have been of the traditional polyester resin type. but epoxy boards have become popular over recent years.

sooo, what kind of resin should be used for repairing boats? in retrospect, sometimes when i walk past the repair yard at the local harbor, [santa barbara, ca], i smell the scent of polyester resin. sooo, think that's it?

-peter

 

[oops!]

Re: which resin for fiberglass hull repair

this question is a can of worms......lol


poly resin is just fine for repairs till approx 1990.....some boats after 1990 were VE resins...(vynal ester)....stronger than poly.

epoxy is only used on really fast offshore boats or racing hulls that need the stregnth that epoxy will give.

for the average 14-28 footer on these forums, epoxy is wayyyy over kill

cheers
oops

 

[erikgreen]

Re: which resin for fiberglass hull repair

So, being that I'm usually providing epoxy info to balance Oops' poly info, I'll do that here, too.

The things epoxy does for amateur builders and repairers are that it A) works with any previous repair.. you can't layer poly over VE or epoxy, including stuff like Marine-tex or epoxy based adhesives.. and B) its excess strength gives unskilled or in training boat repairers leeway to make mistakes. Even if only half your material ends up glued right, it'll probably be as strong as needed. Epoxy is much more tolerant of bad prep than poly too, although really bad prep will still fail. It needs a clean surface, and roughing the surface helps, but it'll still stick to a smooth, clean surface hard enough to work.

On the down side, epoxy costs a little more... if you buy it at the right place it's about 25% more than poly, if you buy it at the wrong place it can be %100 more. Also as mentioned once you repair with epoxy you can't put poly over it later.

The other thing is the poly needs mat for adhesion, epoxy doesn't. So to attach a layer of glass to a piece of wood, you have to put mat down first, then whatever woven fabric you like. Epoxy you can just put down the cloth. Epoxy is, as mentioned, lighter for a given strength needed than poly. But unless your whole boat is built to be light, saving a few pounds on a major repair won't buy you anything.

The choice is yours, there are people here who can help with either resin.

Erik

 

[oops!]

Re: which resin for fiberglass hull repair

heh heh heh......erik....im watching this one with a big bowl of popcorn!!!...lol

 

[Chris1956]

Re: which resin for fiberglass hull repair

I almost side with Oops. However, I have never heard that polyester is incompatable with Vinylester resin. I had also thought that the vinylester was usually restricted the outermost layer on the hull, for extra waterproofing. This of course, would mean it is compatable with poly resin.

I know that poly can be put over epozy and vice versa, because I have done it. All surfaces need to be dry, solid and sanded smooth, as with any coating that you want to adhere.

Oops - Please pass the popcorn

 

[oops!]

Re: which resin for fiberglass hull repair

I almost side with Oops. However, I have never heard that polyester is incompatable with Vinylester resin. I had also thought that the vinylester was usually restricted the outermost layer on the hull, for extra waterproofing. This of course, would mean it is compatable with poly resin.

I know that poly can be put over epozy and vice versa, because I have done it. All surfaces need to be dry, solid and sanded smooth, as with any coating that you want to adhere.

Oops - Please pass the popcorn

munch munch

one thing....poly cannot be put over epoxy.....they are not compatible....yes it will seem to stick.....but the bond is really weak.....well below maunfacturers specs

you are totally correct about mfg's using a better quality resin or a ve as a first layer next to the gellcoat.....in the early nintys
sea rays switiched to ve resins......

my idea is to pick one and stick with it !

want butter with that chris...

cheers
oops

 

[ondarvr]

Re: which resin for fiberglass hull repair

Carry on.