I had never used epoxy before, but i got hold of an unused closed cans of sicomin resin past their shelf life not knowing if the epoxy would be good, but they were ok. ( So since they are ok i dont want to waste the epoxy in order to save it for other projects)
So i laminated bottom and deck of a shaped blank with the epoxy.
Question is:
Can i do the hot coats with silmar pu resin on top of the epoxy lamination?
Will it work?
Any special care sanding or preparing the epoxy layer before applying the pu resin?
I wouldn’t mix and match. I’ve heard poly and epoxy don’t play nice. From what epoxy work I have done, don’t touch the board with your bare hands as it’ll transfer oils and really dust it down well before you seal coat.
Epoxy goes over Polyester but not the other way around. It would be safest to stick with Epoxy for the hotcoat. Epoxy can get a bit tricky so make sure everything is spotless and by all accounts try and apply it reasonably thin. The search function will be your friend!
If the blank is not PU, I wouldn’t do it.
I have done this a couple of times in the past. If there are any pinholes in the lamination the Poly resin will eat the foam and you will have a hollow spot. You won’t know there’s a hollow spot until you have to fix it. I found out the hard way.
If you do it, rough up the epoxy really good.
Cheers and good waves.
I went all epoxy and i am happy with the result.
Also i read most of the topics on pu hotcoat over epoxy lamination and there was one about adding wax to the mix like in the pu resin, witch i did but i think was unnecessary, the bubbles from the wax did not show up after drying
Lots of people do it, i know of several professional one pair of hands surfboard creators who do…
Tell us more. I have been using epoxy over polyester resin for years, I don’t have any polyester resin in my shop, all my repairs and rebuilds are done with epoxy.
However, using poly over epoxy is something I am not familiar with at all. By all accounts, from those who work with it, there are bonding issues using it over epoxy. Your comment is the first I have heard of this being an actual practice among some professional glassers.
Never personally tried PE over epoxy.
I have read on boat forums, polyester over Epoxy is taboo.
Remember stories of PE gloss coats over epoxy shattering and flaking badly at fracture ding sites. Happened on early epoxy/EPS Spherical Revolver remake I bought from Harbour during the Clark Foam debacle.
Found this link when this thread first popped up (last line under PE Characteristics).
I know that my mate and a few others here on the sunshine coast have done it a fair bit.
Laminate with epoxy, maybe a bit of excess resin… Then sand it. Then blow off all the dust.
Apply a very thin layer of poly with a scraper, then brush on the hot coat as per normal. Sand the hot coat,
I have a board that I shaped and laminated with epoxy, then My mate did the poly filler coat on it. Board was awesome. Did get one knock on it where the filler coat separated from the lamination a little, but only the size of a 5 cent piece. I chucked some Duraresin ( a toothpaste consistency tube of emergency ding fixing product that’s suitable for both poly and epoxy) on it. I gave the board to a mate and he has had if for about 2 years.
Ok,
So i went to talk with a guy that handshapes for more then 30 years on a regular basis, as is brand and sells a lot of boards.
I asked him about the pu resin over epoxy as hot coat question and he awnsered the following:
Before you couldn´t do it, but with the new resins it works good (he just does the hot coat with the brush over the laminated epoxy.
I asked what resin he was using and took a picture of the can
he also showed me a bord done that way and it looked good
I had a photo of the epoxy he was using
cheers and good waves,
