I have laminated the bottom of my first surfboard with Epoxy resin, but have run out. It is very hard to get this type and I was wondering if it is possible to finish the board in polyester resin as it is cheaper and more accessible. Has anyone tried it? Is it even possible or recommended? Why?
Chris
Any help would be greatly appreciated as I don’t want to totally screw up my first board.
thanks
Plenty of people have used gloss coats on top of epoxy with good results. How far did you get in your glassing schedule? Do you still have to complete the hotcoat?
From what I’ve read, it’s not a good idea to combine the two resins in a place where strength and adhesion could be compromised. In other words don’t do your lam using both resins. Not sure about hot coats though. there are many experts here.
I have only laminated the bottom and I still have to laminate the top and apply the hotcoat.
then get more epoxy…RR ships quick
Chris,
I’m pretty sure you’re going to get a unanimous vote to definitely to not risk combining the two products during the lam and/or through the hot coating stage. What Soultice said: “best to get more epoxy”.
Best luck,
Herb Bean
Where are you? fill out your account profile… who knows there might be a swaylocker right down the street who will drive some over to you…
i’d stick with epoxy… if it takes a while to get it sand it and scrub it with denatured before moving on…
Hey topher, sounds like you are in a pinch. Here’s a little tip that might work if you can get your hands on some clear, linear polyurethane paint.
If you can get to a boating store this stuff is pretty common. It is a special paint that has a hardener/catalyst. You can buy a pint of some budget clear coat for about $25. Mix it up and with a plastic spreader put a clear coat on the epoxy lam where you will be glassing over with polyester (probably the entire epoxy lam). The LP “tie coat” will allow for a chemical bond. Your hotcoats can be put on the board as normal.
Come to think of it, you could risk it and go for just a mechanical bond from the weave of the epoxy lam. As the other forum members said, it would be a gamble at best, but if your lam is a bit dry with “pin airs” then you will get a decent bond, and you could sell the board to a friend you don’t like…
…you could just claim that you’re just a surfer, not a chemist, and that some idiot on Swaylock’s told you to “try it!” he hee…
Hey Plus One Shaper. Have you used the method you describe? The reason I ask is. I am repairing a epoxy glassed board that has been finished with poly. I’m not prepared to put poly over epoxy. This may be the way the manufacturer gets around the poly bonding to epoxy problems. Any advice would be appreciated. platty.
Hey Platty,
yes, I’ve had to use a “tie coat” for surfboards, boat repairs, funiture, and a pwc modification. From all I’ve seen they are all still holding together. There was a website describing the technical aspects, I think it was the site that involved SB-112 epoxy (system 3).
I’ve put poly over Resin Research epoxy that was sanded very coarse and it seemed to adhere but in time I bet there will be separation.
HTH.
During my boat repair days, the rule of thumb was epoxy repairs on polyester boats are fine. But, polyester repairs on on epoxy boats will pop. The reason I was told was epoxy is more resilliant and can flex further without failing. Based on that, I would not put polyester over an epoxy base, unless I majority of your glass schedule is done in polyester. And, then you’re just adding too much weight.
Poly hot or gloss coats over epoxy?
Patagonia does it.
Epoxy Pro / XTR does it.
Bert does it (according to his japanese website).
Seems like a few pretty germane endorsements to me…
Thanks PlusOneShaper. I will get some and give it a go.
The reason I am not prepared to put poly over epoxy is for the last 23 years I have been working in the composite boatbuilding industry. Not one of the companies I worked for, and I have worked for some world renound yacht builders, put poly over epoxy. SP Systems has a interface that will allow poly to bond to epoxy but the last time I used it, it was white and very thick. So the clear polyurethane will be worth looking into.
I did a test panel. I’m using West System epoxy. One layer of 4oz, let it cure for 24hrs. Sanded it with 60g. Sprayed half with auto acrylic. Left to cure. Then hotcoated the panel. Left again 24hrs. The hotcoat peeled of the 4oz with ease. The hotcoat stuck to the paint but the paint peeled of the 4oz.
I am aware that there have been claims by epoxy manufactures and suppliers that poly will stick to epoxy. But experience tells me not to do it. platty.
it all depends on which systems you use …
i do use polyester gloss over epoxy on most boards …
if epoxy is sanded polyester will stick , like tom said poly wont bend as far but in a gloss situation , your working the final gloss coat down to nothing so its paper thin and will bend quite far , if it bends far enough to crack , youve down enough to cause some damage anyway …
if you leave your gloss to thick , it can crack off while still leaving the epoxy underneath in tact , thus showing how poly doesnt bend as far …
another big but is , not all epoxies except polyester even when sanded , the amount of pain ive been through when it comes to glossing , when ive been trying a new system and i find its not compatible …
will leave my theories out for now …
in this situation , its glassing not glossing …
one plus you have is the bottom is lammed in epoxy , so if you agressively rough up where the laps will go that wrap from the deck , your going to expose fibres , in doing so you will create a better bond …
i believe you can get away with the poly but wouldnt recomend it …
and that is only on the condition that the epoxy system is the compatible type …
question . what brand of epoxy and system ???
it may be in the memory banks as a wo or a go …
regards
BERT
i do use polyester gloss over epoxy on most boards …
I thought that you used a 2 part urathane spray from U-Pol for your gloss coat.
most boards…
the upol is way more resistent to cracking so it works well on the lightest flexiest boards …
it depends on the glassing schedule …
but mostly use upol for team boards now , where looks isnt as important as reliable performance …
polyester shines up way better , so goes to the guys who want looks …
regards
BERT
What I find challenging about composites is you have to do away with the one size fits all mentality. Its going to take me awhile to get used to not viewing materials as good or bad, but rather what they will add or take away from the board.