runabout renovation - polyester resin?

I just got my copy of Runabout Renovation (thanks to somebody here who pointed it out) and the author suggests using poly resin for repairs.. Is that simply because epoxy was really expensive when the book was written?<br /><br />The reason I ask is that I like using poly resin, I like being able to adjust the drops of catalyst to control the curing speed (as opposed to having to keep multiple catalysts on hand). Not to mention that I can mix one ounce easily for small repairs.<br /><br />I'm mostly filling small holes and gouges in a 1969 fiberglass boat, obviously if I use poly I'll need to sand the surface prior to application and watch for shrinkage..

Re: runabout renovation - polyester resin?

He suggests poly because thats all you really need. Its how the boat was originaly built, no need to go beyond that. I feel that epoxy is best served when improving or modifying, and you need the extra bonding strength. You still need to do the same prep work for epoxy that you do for poly, so there is no advantage there. I also like epoxy for fixing hull breaches and that sort of thing. Otherwise, unless the wallet is bottomless, epoxy isn't needed.

Re: runabout renovation - polyester resin?

That's what I thought. I've got some West systems epoxy here that I'll use up.. but I'd certainly rather get a gallon of poly at $25 rather than a qt of epoxy for the same..

Re: runabout renovation - polyester resin?

Before you start ordering over the 'net, look locally for shops that repair and customize fiberglass boats. If you talk to them, they will be more than happy to sell you bulk resin, and it will be cheaper. I paid something like $17 a gallon for poly from a shop an hour from my house. I got all the mat, resin, catylist, all that from them for something like $280 or $300, can't remember. I had talked to them about epoxy and they said it just isn't needed unless you have money to burn or really really really want that extra peace of mind. Also, remember, you can apply Poxy over Poly, but not vise versa.

Re: runabout renovation - polyester resin?

If you want extra security, paint your work twice with epoxy or ureathane primer. I had a norwegian Fjord daycruiser from 1976, Hull was painted everywhere internally. No rot or damage anywhere. way to go !!

Re: runabout renovation - polyester resin?

One other thing I seldom see mentioned is that Epoxy Resin can be layed over Polyester with no problems. But Polyester does not adhere well when layed over Epoxy. I don't know exactly why that is but I have seen it mentioned on a few of the manufacturers sights.

Re: runabout renovation - polyester resin?

In making a choice between epoxy and poly for my little modification job,<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=26;t=000829 <br /><br />the instructions on a can of poly said "must use with cloth or mat" that poly used alone, with any depth would shrink and crack. So I opened up the vault and walked out with epoxy. This is in keeping with JasonJ's advice to use epoxy for mods and improvements where strenth is necessary.

Re: runabout renovation - polyester resin?

anderson uses microballons mixed with resin to toothpaste consistency to fill holes and cracks and the like, no mat ... <br /><br />I love that book, I tell everyone to buy it, even if they DONT want to restore a boat, they will see why its so important to keep her dry!<br /><br />I bought mine brand new, and it looks like its five years old, I should study my psych books as intensely! LOL

Re: runabout renovation - polyester resin?

hey boomyal,<br />did you buy that 'poxy online?? remember that if you intend to use epoxy to glass in matt, must be sewn matt as i understand (learned that here). i get my sewn matt from uscomposits, as well as epoxy--------paid $45 for 2 gal 150 slow epoxy--(for laming wood, not laying glass their tech folks told me), and will pay $45 1 1/2 gal 656 thin epoxy--best on line deal i found. i did check with some local glass shops and supply vendors and they wanted much more(probly my ugly mug and BO)<br /><br />anyhoo, reason for sewn matt is that more common matt has chemical binders to keep same from falling apart--binders desolve w/ poly resin and all is well--am told that binders interfere w/ epoxy.<br />i like epoxy 'cause it dont stink