Alright, I have searched the archives and not been able to find what I’m looking for. I’m considering glassing my next board (4th) myself w/ RR epoxy. My biggest concern is the feel in the water. I surfed my cousins flyer which is an epoxy board but xtr foam and it felt like a baloon on the water. If I were to glass a pu blank w/ epoxy resin please tell me it will not feel the same as the flyer… Is the feeling similar to poly or does the epoxy give an entirely different feel?
And if I missed a thread where this subject has been covered could you please direct me.
the polyurethane boards with epoxy glass jobs seem to work well, they are very fracture resistant although they dent a little bit easier and they flex great and feel very alive compared with polyester resin.
Using epoxy on pu your board might even be slightly heavier than if you used PE resin. People try to skimp on the epoxy with the lam then have to use more epoxy for the filler, then gob more on for the final coat. Sanding is different as in doesn’t come off as quick. I don’t think you will be disappointed.
Other way around Otay. A 6 bottom 6-4 deck with epoxy is the same weight as a 4 double 4 with polyester. Epoxy is lighter and glasses quite a bit lighter.
Sanding is vitually the same if you use Additive F in the hot coat.
Get the new “Blue” RR epoxy for PU, and you’re good. Call Brian at Greenlight. He’ll get you some.
As far as the feel, it feels great.
As far as the sanding goes… I think if you sand it sooner rather than later (like the next day), it sands easily. If you let it fully cure (I sanded a board that cured for 6 months) it seems to sand a little harder. You can ask Greg for the data, but that’s been my experience.
the polyurethane boards with epoxy glass jobs seem to work well, they are very fracture resistant although they dent a little bit easier and they flex great and feel very alive compared with polyester resin.
Epoxy glass over PU will not dent easier than poly. It’s much tougher than poly if you wait to surf it after the epoxy has fully cured (approx 1 week). Post cure the epoxy glass job with heat - even tougher.
Denting also has to do with the quality and compression strength of the foam you’re shaping.
Fracture resistance and flex properties of epoxy are far superior than polyester resin.
The Blue colored Research CE resin is available broadly now and solves the issues of protecting usethane foam with a UV package. This includes an optical brightner which keeps the resin itself whiter, longer and a UV absorber which protects the foam.
My guess is I’ve built more PU/epoxy’s … I built one at Pac surfglass , Ultralight Clark blank with single 4 oz both sides with a deck patch. Came out right at 4. Pretty disposable but the same board built with polyester was 4.75 … also disposible. Did that with DHD … it was on their website. Epoxy just laminates lighter. Quality makes a difference for sure but there are plenty of quality laminators out there now that can do both. And for a novice laminator epoxy is wayyyyy easier.
If it’s bagged you want then the Coil boy’s will blow your mind.
Please believe me … This is nothing new. Common knowledge where I come from. Where’s Daniels … I need a Coil guy here … they know. Also PE resin is 9.7. Epoxy is 8.8 to 9.2 mixed depending on which system your using. Lots of theories on this because the weight of the resin itself doesn’t answer the whole deal.
My personal theory is that the fabric lays flatter with epoxy because of epoxy’s better surface energy. A four ounce epoxy will also dent a bit easier than a 4 oz. polyester. That is explained in my theory because the loss of relative thickness would explain the denting. At our FL factory we do 6 bottom 6-4 decks on urethane blanks so they come out the same weight as a 4 double 4 of polyester and are actually (not surprisingly) stronger.
As far as polyester VS epoxy in use amounts, this ain’t close. The determining factor as to which resin will wet out isn’t only viscosity. It’s surface energy. Epoxy is vastly superior in surface energy which is one reason why it’s such a good adhesive. Along with poor surface energy, polyester is solvent based which is where it gets it’s low viscosity from. As soon as it’s poured onto the board it begins to evaporate. You have to get the laminate done in a hurry before that evaporation leaves you with a sticky mess. UV cure resin doesn’t even kick when your working with it and yet if you spend too much time it gets so sticky you can’t effectively move it anymore. The solvent leaving is also costing you material as you work which is another reason you have to use more.
We build epoxy boards with 40 ounces of resin/hardener. That’s our standard useage for shortboards. I’ve never talked to any polyester glass shop that didn’t use at least 96. Most use 128. In fact Kechele used to go around town bragging that he got 77 boards out of one drum. Back in the old days when it was all 6 oz. glass jobs and thick hot coats we used to get 35. And that didn’t even include the gloss. Out of a drum and a half mixed we get 250. The board Sam built in the WMD compsand thread used 24 ounces … TOTAL! That’s three cups! A drum and a half could make something like 400 boards. And at the price of resin today epoxy saves a TON of money. $12 a board for epoxy vs. $22 for polyester (those are drum prices). $10 a board less. Again this is common knowledge.
Polyester laminators who aren’t experienced with epoxy fail to understand how to work correctly. They’re used to dumping the resin on and running around the board forcing the resin into the fabric. With epoxy you just spread it around and stand back … it does it itself. The way I laminate is to spread the resin and then wet the rails. By the time the rails are wet the resin has done all the work on the flats for me. Now I just clean it up tuck my laps and I’m done. Wayyyyy easier.
Back in sailboards we did sandwich deck and bottoms with Clark sheet foam. Glassed the bottom and rail with epoxy, flipped the board and laminated the decks with polyester. These were a pound heavier than when we laminated both sides with epoxy. Ask RF … I’ll bet he knows too. Be surprised if he didn’t.
