Resin separation on rails ,,,Why? need knowledge please help

Hey guy’s

when I did my last board all went well untill the gloss coat on the deck.

what happenend was ,

I got 1 gallon of gloss resin ,added one pouch of uv hardner and mixed well for a few days

preped the board ( 100 grt sand and acetone wipe and taped off)

filtered resin and applied (coating the whole deck and rails) then tipped off

let set for a few minutes before opening the G door and …

The rails have separation lines in the gloss coat (like spredding your fingers about 1/8 to 1/4 inch)

but not on the deck only the sloped rail areas

the deck was lile a sheet of glass

I sanded and recoated and got the same result

you resin guru’s know whats goin on here?

Sand it off and try it again with catalyst. Splitting means too much resin and/or not enough catalyst. Don’t try to UV cure a glosscoat.

Beg to differ, my UV finish coats come out okay.

My process is much like yours BUT I use premixed lam resin, and add my own surfacing agent and a shot of styrene to thin things out. Results are fine, within the somewhat dusty limitations of my garage.

Wonder about the mixing you’ve done, and the amount and quality of powder that went in.

Physically, sags suggest that either there’s shrinkage going on, or that the underlying resin, next to the hot coat, is not going off when the resin above and exposed to the air, is gelling. Hmm.

Bambam are you suggesting he set his finish coat off faster? I’m always afraid that the wax won’t rise, but Clayton (helmethead) always says to set off the finish coat really fast, so I suppose his wax always rises…

Howzit Kensurf, Most of the time it’s due to too much resin left on the board so it separates. If the surface was contaminated you would more likely get the fish eye affect not separation. Yes some times a fast kick off will stop it before it happens but I have seen where slower kick times will make the resin actually reflow back over those spots and fill them in. One trick is to mix more resin and paint over the separations right after the first batch kicks, this will require some extra sanding during the rub out process but that’s better than resanding the whole board and reglossing it. Separation can also occur when doing a hot coat. Aloha,Kokua


I have used UV hardner in the 1st board I made and had no problems like this

I didnt even filter the resin and it was the same brand and same uv cat



I dont know about the quality of uv powder, it comes in a bag and says to add to 1 gal of resin, of which I did

I tried getting it into the sun as fast as I could but it saged before I could move it

What do you meen by premixed lam resin

I use lam resin and add surfacing agent for sand coats and havent had a problem with that step

Like I said ,I’ve used this before with no problems, actualy came out perfect on the #1 board


I did lay it on thick but I’ve done it the same without any of this separation

maybe I need to thin the resin with some styrene, the gallon I got does seem a bit thick. its supose to be ready to go.

I didnt try to let it set cause the first thing I thought of was to get it gelled asap

I tryied a double tip out but that didnt do anything

maybe letting it set for awile in the garage would have given it time to flow out , but it looked to me like it was done

Is it possible to get a bad gallon of resin?

Maybe I will just use lamming resin and blend it myself with surfacing agent and styrene

what do you do for polish finish? anyone can respond

Howzit Kensurf, I would say you were lucky before when laying it on thick, it doesn’t have to be thick,glossing resin loves to separate if to thick. But you are probably trying to get it thick enough so you won’t rub through when you rub it out, right. As for bad gloss resin, yes you can get an old bad batch. The way to tell if it’s bad is you will see white residue in the bottom of the can,shine a light in to the can to see it. Now if it’s bad it will usually not kick as fast ( probably take twice as long or longer )as it should so just add some lam resin and a little extra it and it will kick faster.Shaking the can will not remix the residue back into the resin. Shurlustre is the way to go for rubbing compound but if it’s not available use some course compound and then fine compound, this is how we did it before shurlustre came along. Have you tried my gloss mixture? Aloha,Kokua


thank you for responding

I think this gallon of resin is a bit thicker than the last stuff I bought 1 qt to do my kids board

I think I need to get some styrene, how do you know how much to use?

If I would have let the board set before putting in the sun to cure, do you think it would have flowed out?

or was the resin just too heavy to hold itself together?

incase you didnt see her attached is the only pic that will attach


Have you tried my gloss mixture? Aloha,Kokua

Hi Kokua,

I’m about to do my first gloss coat and I’ve been reading all over about your famous mixture, but for some reason I can’t find exactly what it is. Does your mixture entail adding additional styrene (10%?) and surfacing agent (5%) to gloss resin?..or is it a recipe for making gloss resin out of laminating resin?

I’m planning on using straight gloss resin from the can (reichhold), with about 4% catalyst. But I get the feeling that your mixture calls for additional styrene and surfacing agent. Am I correct?



Ya we need to know!!!

Howzit speciak, You've got it just add to the glossing resin, run everything through a filter even the gloss resin, then stir in the center of your container so it makes an eddy which draws every thing down the middle like flushing a toilet. The only thing is I use 25 cc's of catalyst sincw our humidity is high so you might have to adjust. But there are others who have used my mix and maybe they can chime in and give you some info on the cat amount. Aloha,Kokua

thanks kokua!


What is the complete recipe that you use


resin ?

cat ?

surf agent ?

I like the uv stuff can I add regular cat?

Would thick resin have eventualy flowed out over the rails?

Howzit Kensurf, First use one of those plastic quart containers that shows measurements on the side. The amount of glossing resin is determined by how big the board is. Now add 10% styrene and about 5% S.A. to the mix. Like I said before I use 25 cc’s cat but that might not apply to where you live due to your environment conditions. Yes you can use catalyst with UV resin ( that’s how I do my hot coats). The gloss job will be a little thinner but smoother so you won’t have to sand it much during the rub out process.Hope this is what you need.Aloha,Kokua



so the standard uv mix is good?

is 5 % sa added to the gloss resin that already has some sa in it?

what do you think of the board? does it look like a 70’s bolt?

Howzit Ken,Yes,Yes and Yes.Aloha,Kokua


you are a gentleman and a scholar.

Thank you for the knowledge that your passing to me.

You said that I can mix cat to uv resin, but do you do that?

If Im adding styrene and more sa. shouldnt that smooth things out?

Or should I through in the cat just because,

If I get a good gloss coat layed on can I start with 400 wet sand?

(of course after fareing in the tape line on the rails)

Howzit Kensurf, Yes I use catalyst with UV resin,in fact the only time I don’t use cat with it is when doing laminations. You will need to use cat when doing fin boxes and leash plugs. Don’t understand what you mean by “or should I through in the cat just because” or do you mean throw.when you get a nice smooth gloss you can start the deck with 400 grit but even with a smooth gloss I start with 320 on the bottom with a blue hard power pad. Aloha,Kokua


I realy appriciate you hangin with me on this.

Yes I ment “throw”

Is that 320 wet sand or does it matter wet or dry?

“Blue hard power pad” Is that to keep the bottom flat?

Can I block sand the bottom?

One more thing, call me crazy, but I kind of like wet sanding by hand.

question, do I have to go in circles or can I sand length wise nose to tail?