Resin Drained!

So in glassing a 9’4" Longboard, decided to do the oldschool leash string through the fin box. Box is in all fine with two sheets of 6oz cloth, hole drilled through deck. Put some masking tape over the hole added plenty of resin with catalyst added cause it was uv resin. Toook the tape off about 8 hours later and resin just all poured out deck hole. The box is in solid cause that resin kicked, thinking about just mixing up a thicker bacth with more catlyst and pouring in the deck hole, then sanding etc. And most likely going to add a patch on the bottom to make sure the box is in real solid. Wanted to double check if you guys would use the same method. – Jolly Mon  

How big of a batch of resin did you mix up?

When you say make it thicker, what do you mean? ( your mix will become thinner with the more hardener you put in)

It sounds like you mixed a small batch and put too much hardener in (all hardener and no resin)

It should only take a few drops of hardener to kick enough resin to do the job.



I did not know that seeing as how I have only used epoxy before this explains alot more, so this time around less hardener more resin. 

If you put so much hardener in a batch of poly that the resin becomes thinned out, it will catch fire!!! A concentrated mass of resin with excessive catalyst gets hot as hell. Something tells me you forgot to add any catalyst, at all. We’ve all done it.

Was the fin box done with a separate batch? What measurements did you use for the resin to catalyst ratio?

Sammy… i was thinking more along the lines of a silver dollar sized pool of resin, not a bucket full. Haha

If you drill a 1/4" hole through your finbox and the deck of a board, and fill it with catalyzed poly, that is a significant mass of resin. The more concentrated the mass, the more heat it produces. You could take that same amount of resin and spread it over a broad surface and it will take longer to kick, and produce no heat to speak of.

When I was laminating boards on a regular basis (as many as six a day) I would mix 1 quart batches in one gallon buckets instead of using 1 quart buckets.  It slowed the resin down and allowed more working time. The greater the surface area in a given batch, the less heat it creates.


Straighten it out as you specified --Jolly man.  Jut fill the hole.  Cabosil is most often used to thicken resin.   Next time put a piece of tape over the hole pressed down firmly so that it doesn’t drain.

If the resin was still in liquid form after 8 hours, you did something very wrong, like forgetting the catalyst. Just do it over, and CONCENTRATE this time.

I most definetly add catalyst I think what happened was I added to much the resin was super thin, cause all the resin directly exposed to sunlight and the resin aroud the box mostly kicked only about 1 1/2 oz’s drained out just leaving the hole empty. Since the box is hardened and set it should go much smoother this time because the hole will be exposed to direct sunlight, instead of under tape. Thanks for the advice I did not realize how much catalyst can toy with the viscocity of the resin. 


Again…if you added so much catalyst that the resin became runny, it would have gotten really, really hot. I’ve seen resin batches in rail dings crack and smoke from the heat generated because the ratio was way off.

Do you have any idea how much catalyst you used, or how much resin? I mean actual numbers of liquid measure.

Just so you have a clue, next time…poly resin should get 8-10 drops of catalyst at a working temperature of 70f. For a 1-1/2oz batch, 12-14 drops should do it. Lower temp? Add a few drops. Higher temp? Adjust accordingly.


Thanks man, that was probably a large factor as well, was just above freezing when I did it last. This winter just wont let up. 

From “Essential Surfing” by George Orbelian (3rd edition, 1987)

Page 223


You should not be working with poly resin in temps below 55f. That’s asking for trouble

At the very least, warm the resin in a bucket of hot water, or keep it indoors until you’re ready to use it. Then use it quickly.

Not sure if you added pigment to the resin, but if you did, that could have effected it also.

I think the low temps had more to do with it than any other variable.

Yea and this weather is not getting any warmer just have to mix a nice thick batch on the next cold day. Swaylocks knowledge pulling through again.

What the hell? Are you working outside?