epoxy surfboards

Can anyone explain to me why a vacuum system is used on epoxy surfboards? I don’t know very much about epoxy but I am thinking of shaping a board in epoxy.

Vac bagging is done to create a stronger lamination and use less resin. It doesn’t have to be used when glassing with epoxy, but some prefer it.

Note that I used the the term “glassing”. Why? Because you do NOT “shape in epoxy”. Epoxy is the type of resin used to adhere fiberglass to some foam boards, or even wooden ones. The other commonly used resin is polyester. Resin is not used in shaping. It’s applied after the shape is finished to bond the fiberglass cloth to the shaped blank…

Sammy, Thanks for the response, I did say shape didn’t I, I was using that as a general term since when glassing with epoxy one has to use a different type blank. I should had said build an epoxy board. I was hoping for a more indept explaination other than some people prefer it. For instance, how does it make the laminate stronger and how does it use less resin. It’s my first time on this forum, bear with me and I’ll get the terminolgy down soon. thanks bro.

Its not required

it’s only used as a giant clamp to squeeze or mold things in place

and force out excess liquids, resin infusion is a more sophistcated way of doing the same in composite manufacturing

its comes from the composite industry and not really needed to glass a surfboard in epoxy if you’re weighning all you material carefully.

all you really need is a good digital scale if you want to get really technical

and even then that’s not needed

just know how to do a good tight glass job

as far as strength the closer you get to a true 1 to 1 ratio between the glass and the resin the stronger the end product the more resin or glass you have in the ratio the lower the overall strength but it’ll still be plenty strong.

The reason why most epoxy boards are stronger is because you start off with a superlight EPS core so you can add more layers of glass(support) on the outside to get to the same weight of a heavier PU core board. So for the same weight you have more layers of glass/resin on the outside.

Vaccum bagging on those layers on allows you to drop the weight down by squeezing out more of the excess glue (which epoxy is) from the process…

As far as shape goes

the biggest mistake most of the surftech shapers made was just building the same spec in epoxy as they did in PU.

For without accounting for the strength benefits of epoxy the boards ended up way too thick for the molded process and hence too stiff. Only Donald Takayama with his In-The-Pink model and some others adjusted their shapes to take advantages of the stringerless molded hd-foam skinned construction. So those shapes actually ended up surfing to their potential. Stiff and light really didn’t work but once the snap/flex was allowed to show in the end product the boards really sparkled. This was the premise of Bert and Loehr’s whole perimeter/parabolic stinger adventure which became firewire. Adjusting the foil to fit both the material and the shape is what seperates companies like Coil and Surflight from the rest. Even Libtech with all its great technology didn’t understand foil when it came to their first generation shapes. But then they seemed to only be concerned about eliminating dings than performance which is what Coil has been persuing.

When you are designing something you need to take into account all the aspects of the end product, including materials. That’s all you really need to know about epoxy its just different materials with different properties.




No, you don’t. You can use any kind of blank with epoxy resin.


The pressure from vac bagging creates a better glass to blank bond. Less resin is used because you are not trying to wet out the glass by hand, which is less uniform or precise. The vac process infuses resin into the glass a lot better than a hand held squeegee. Only highly experienced pro glassers can achieve by hand, close to what a vac job does.

You should use the search function on this site to answer most of your questions. This is really basic stuff that has been covered over and over ( and over) again. For instance, the phrase “epoxy board” is a misnomer. Technically, there’s no such thing.

You will need to learn a lot to vac bag a lamination. You will also need a lot of supplies, including the vacuum pump, the vacuum bag, the bag sealing system, breather cloth, peel ply. You will need to be able to wet out your glass, get the glass on the shaped blank, wrap it with the peel ply then the breather cloth, into the bag, seal it and smooth it all out while pulling the vacuum. It will take a few times to get the process down even if you have someone showing you how to do it.

The plus side is that if you do it right, you will have the highest strength to weight ratio in the glass. You can mess up and get wrinkles that will be a lot of work to fix.

I think a lot of the epoxy boards are made in molds not vacuum bags. They are placed in molds in layers then the molds are placed in an autoclave to cure. Once out they just clean up the edges.

sharkcountry has a good point. If you’ve never glassed a board before you’re better off doing a hand lam. Why complicate what is otherwise fairly simple?

Orca;  Don’t feel bad, the majority of surfers that don’t know a shaper have a lot of confusion about what makes a modern surfboard.  Some of the points have been made above by the aloha brothers (i say that with love brudas) and by Sammy.  I think you need to understand what you are asking in your basic question.  Most surfers refer to “epoxy” surfboards in that the board is made using an EPS core which will only be laminated with epoxy resin & fiberglass cloth.  Polyester resin will melt EPS.   Polyurethane cores (the first “foam”) are the standard in the industry, and can be laminated with epoxy resin & polyester resins.  Both resins have their own characteristics, but the fiberglass cloth that gives the strength is always the same.  Epoxy resin is expensive compared to polyester, and the characteristics of the resin as well have led to the development of various techniques and resin formulae in the manufacture of production surfboards.  If you want to learn how to make a surfboard, please investigate “old school” PU/PE construction.  Later on with some basic skills in place you can try your hand at EPS core and epoxy construction.  There is a third type of core known as XPS (extruded polystyrene) which can only be laminated with epoxy resin & fiberglass.  All these different types or construction require a basic skill set and each variation requires additional skills.  Start simple I always say!  Just my 2c…

You don’t have to use the vac bag to make EPS or XPS boards with epoxy resin. Standard hand laminations are done by most people. It’s just the few who want to get the best results for strength to weight ratios, and who may be using exotic cloths or combinations of materials for the skins that really need to use the vacuum bagging. Probably another plus is that if you do it right there’s very little sanding after the initial lamination. It depends on how you do it. A lot of work up front and less work after it’s cured. More material costs up front, but you re-use a lot of it.

I talked to a kite/wind surfer from Australia and he said he only does the glassing in a vac bag because the strength to weight is way better. But these guys need really strong boards. They use a light core and add more to the skin for extra strength. They all have their little secrets to materials and what not.

EPS or XPS foam and epoxy resins are available to many people living far away from where most surf supplies can be found. You can start with simple standard surfboard building techniques but using the EPS foam and epoxy resin instead of the standard polyurethane and polyester materials. The down side is you’ll have to hack out a surfboard from foam that doesn’t already have a basic shape. Plus side is if you get good at that, making standard boards from PU/PE is a piece of cake.

Vac bag allow a better fiber/resin ratio by compacting fiber and if you use good consumable (perf ply, bleeder) you can have a bubble free lam. Better fiber/resin ratio allow better tensil strengh. Boards break because of buckling, buckling is flexural mode where fiber/resin ratio is by far less important for strengh. Vac bag lamination is a waste of money and time for surfboards skin except if you use light density fibers that don’t take resin well and float over. Vac bag is needed for sandwich skin tech.

Sorry for my frenglish

I hope I can use your reply form to thank everyone with thier input. I now have a better understanding of Epoxy systems. I never intended to try using the vac. bag system but was only gathering information. I will take your advise and try my first shaping experience with PU which is what I ride anyway. I am considering epoxy later on as I believe the technolgy has improved and one can get the flex I am used to with todays resins. Thanks again !