A few lamination questions...

Dear swaylockians,

A few lamination queries if i may.........

1. I have laminated about 10 of my own boards over the last few years and I have realised that the resin use seems a lot more viscous than that which I have seen professional shapers use in videos. I have watched a number of videos over the last 2-3 years and often I see the laminator running up and down with his squeege with the resin flowing like water. When I laminate it is difficult to get the resin to wet out at any speed other than slow, which can cause problems getting everything done before is gels. I have tried raising the temp to 22 degrees C and warming the resin beforehand because I heard this might help but not much has changed. I know my skill level means I am going to be slower than anyone who has been doing this for a living but I cant help thinking that if the resin flowed a bit better it would make things easier. Do you guys thin out your lam resin or do I just need to move to a warmer country? The resin is from South Africa and is specific for board building.                       

2. Traditionally I have always done a pretty heavy glass job on my boards (6/6+6) just because I am heavy and seem to like short boards that have a bit more weight (maybe that says something about my surfing skill level?). However, a friend has asked me to make him a short board and he wants it glassed light. After a bit of rangling and steering him away from 4/4+4 I suggested that a layer of 6oz somewhere would be a good idea. However, which side should it go? He's not a heavy footed surfer and he wont be pulling any airs anytime soon, so structually which side would benefit from the extra strength?

3. I got a blank from my normal supplier and after hitting the stringer a few times with my plain I noticed that about 2ft up from the tail, there was glue filling in where wood should be. So in one place (about 1-2inch), the stringer is only half the width it should be (the other half glue). Looking at the underside, the glue doesnt go all the way through but certainly doesnt look normal normal wood. I was passing the shop at the weekend so I went in and had a word. The guy was good as gold and gave me a new blank free! But what can I do with the faulty blank, has anyone come across this type of thing before? Any thoughts on reinforcing it or should I glass it as normal and cover it with a design?





I can't specifically tell you what is making your resin thicker.  Do you have photos of your boards, your shop, the resin label, etc.?

I glass with Resin Research epoxy resin, and I keep the temp in my little shop about 75 degrees (24 celsius) with an electric space heater, when glassing, never had a problem with wet-out, except when a batch "kicked" a bit soon, and then it was just because I wasn't paying attention, had I noticed and dumped the batch right away, it wouldn't have happened.

When I have a lot of area to glass, I do it in several batches, since I'm not fast either - I mix up some resin, wet out my cloth, mix up a bit more, and continue.  But if I'm using pigment in the resin, it all has to be mixed at once.

I glassed a longboard blank that was pretty dense and tough (ecotech), I went with 6 on the bottom and 6 on top, lapped the rails, and I reinforced the tail around the fins, and the middle of the deck where I pop-up and stand, with 4 oz.  It seems plenty strong.  If you didn't take a lot of foam off the deck of the board when shaping, I would think you could do the same. 

In the interest of full disclosure: Later, the nose split apart right down the stringer, and had to be repaired, so the nose got another layer of 6 top and bottom in the repair process (I never did determine what caused the nose to do that, but I have suspicions about the ecotech blank - I don't think it was a result of glassing too light.)

Cosmetics aside, I would just finish shaping and glass the defective blank as usual.  Cover it with whatever you want, if desired.  A little creativity goes a long way when it comes to hiding defects!

Basic laminating schedule and technique…

  1. polyester resin can be thinned with styrene. epoxy resin can be thinned with heat, by heating the resin, not the hardener, and keeping all your materials warm, as well as the air in the room.

  2. I’d do 4oz under 6oz on the deck side; 4oz on the bottom. Some guys will disagree, but I like to “protect” the weaker lamination with a stronger one, and allow the stronger one to lap the rails for ding resistance. Just makes sense to me…

  3. Just shape and glass your defective blank, as Huck said. You can patch over the glued area with a 2oz of 4oz patch if it makes you feel better, but really just a cosmetic issue unless your surfing serious waves of consequence.

  1. Don't thin the laminating resin, unless its styrene has evaporated.  In that case, replace the lost styrene.  Quantity poured will affect how it flows.  Pour a little, it's going to spread harder than if you pour a lot.
  2. Give the guy what he wants.  A light glass job is 4+4 deck, 4 bottom.  I think Yorky does single 6 deck 4 bottom for super light, but don't expect it to last long.  maybe adding a patch under the feet might help, but better than that, S cloth and epoxy.  4+4 S-cloth and epoxy is stronger than 6+4 polyester resin.
  3. Good on the supplier for giving you a new blank.  For the final ride on a short board, stringers aren't necessary at all.  They make the board easier to shape, but that 1/8" of wood isn't much.  Just look at a coil.  If the board is for big surf, different story.  If you want to add strength where the stringer is compromised, add more cloth on the rails.  A box beam works just as well as an I beam.

Good stuff!

Cheers guys,

The advice seems to be relatively consistent so that makes things a little easier. I think my resin issue must be largely a result of temperature and I will try to ensure everything warmer before I begin (its difficult to get good temp in the UK and i am impatient). I may add a small amount of styrene (4%) on my next go and see what happens.

I will go with 6+4 on deck and 4 on bottom on current board in the workshop. I will drape the deck patch further down rail on faulty blank to give it a bit of extra strength. 

I am keen to start using S-cloth and Epoxy resin but until now the cost has been an issue. Hopefully I will be able to experiment a bit more when the wedding and honeymoon are over and paid for.....eeekk!

A talked to a friend doing a Phd in composites in the UK and he pointed me to a 'Guide to composites' which seems to be good background info for rookies like me (all of the first year composites students at the University get given a copy on thier first day).


Thanks again for the advice...

I live in Porthleven Cornwall and I know your problem is one of two things…it’s old or its cold…now I presume your problem is the later…when laminating through the cooler 6 months of the year I prepare my resin by filling a mop bucket with hot water…putting my resin in a bucket…place it in the waterbath to let it heat up…remove from bath when viscosity is at desired state…WIPE THE BOTTOM AND SIDES with a paper towel so you have no water dripping onto your laminate…then add cat and mix…

When you are doing this however it’s important to reduce your cat percentage as it will kick real quick when heated.

Do the same with your hotcoat but as you dont need long on the job you can use more catalyst.

Hope it helps.

Cheers Rich



Thanks for the advice and I will admit i have tried this before however I dont think I reduced the catalyst amount enough and I ended up with a stressful and messy lam. What sort of catalyst % do you normally stick when you heat it up out of interest (assuming 20-25% resin?) as i am often afraid of putting in too little.


If I’m doing a warmed up mix I’d reduce the cat right back…that would be around 0.6-0.8 percent so if you’d poured kilo of resin I’d only add about 6 cc -8cc of catalyst. Depending on how warm id got the resin. Like this the resin flows real easy and wets out with ease. On extra cold days it’s also vital to really warm your room up beforehand so the cold blank has chance to come up to temperature. If you don’t the cold blank can absorb the heat from your warm resin and become more viscous as you laminate. I’m still only getting about20minutes to gel time with this setup and it hardens off just the same. None of the boards I’ve made have snapped to date and most of them get a pounding at porthleven here on the reef which is a pretty heavy testing ground.

Thanks Thirdshade,

I have always been afraid to add less than 1% cat, dont know why but I will definately try it next time to give me a bit more breathing space. If your boards are solid at porthleven then thats good enough for me (went out there a few years back on a sponge and got a good thrashing). Will hopefully bring one of my creations down for a test at some point (just about to start shaping a 'one-board-quiver' for Indo) so should be as good a test as any in the UK.

If I am down your way in the future do you mind if drop in to have a look at your operations?


More than happy for you to pop in if youre down this way.

Closest I have ever got to a one board quivver is this board - called the probe - 6'2" epoxy eps multifin. Works in 2 ft but has been put in some big pits here in the village - made it for a mte and he's barely ridden anything else in the past 2 years!




You would probably be fine with 1% if you heat your resin. They recommend 1% when for temperatures over 70 or 80, and you probably won’t get the resin to stay any warmer than that. I like to sit the resin in front of a heater without cat, and stir it periodically. You will see the composition of the resin completely change, from a thin jello to basically water. I had the same problem several times, and honestly things move so much faster with properly warmed resin that you will need less time than you think. When you laminate with cold resin, you basically have to carefully wet every inch of the board, so it takes much longer. 

As people have said, 1x 4oz bottom, 2 x 4oz top is standard for a shortboard. Also, you will notice that the boards will be lighter when you warm the resin, because you’ll be able to pull more out of the cloth, and a lot more will run off the rails.