FAQ About Building Surfboards

Epoxy resins are expensive, are there any alternatives? e.g Varnish, clearcoats

Unfortunately there are no suitable substitutes to epoxy resin.  Epoxy is a tough “plastic” that when used with in combination with fiberglass or carbon fiber cloth creates a super rigid structure.  This structure is what gives the surfboard it’s strength, using varnishes or clearcoats does not harden to the strength or stiffness that is needed.

Is sealing a surfboard blank necessary?

If you are build an EPS board you need to seal the surfboard, this prevents epoxy resin from absorbing into the foam.  The result is the board won’t get weighted down by extra resin and also fills in any holes, or small imperfections. EPS has a tendency to tear out the beads of the foam when shaping so sealing it also allows for an even tint or pigment job.  The best and lightest filler is Polyfilla Big Hole Filler.

I am having problems with fisheyes in my sealcoats, what is causing this?

The dreaded fish eyes, this is caused by contaminates on the surface of the surfboard.  This can be from environmental factors such as dust, oils, waxes, lotions, sweat or touching the surfboard with your bare hands. 

To prevent this, never touch the surface of the surfboard with your bare hands after laminating and the sealcoats.  Inexpensive nitrile or latex gloves come by the box, use them anytime you touch the board.

Also, before applying the sealcoats, wipe down the board with a solvent.  My preference is acetone (yes not great for you) methyl hydrate or 100% isopropyl alcohol.

What is the difference between EPS and XPS foam?

EPS is Expanded Polystyrene, XPS is Extruded Polystyrene.  They are both closed cell rigid foams, very commonly used as insulating materials but have some differences.   EPS is “beaded” foam, in that you can see the beads in the foam, it’s typically white and you see it used all the time as packing material.  It comes in many different densities (try to find 1.5 to 2 lbs/cubic foot) and makes for a rigid surfboard compared to traditional polyurethane surfboards.  It doesn’t shape very smooth and has a tendency to “tear” and must be sealed before glassing.  It takes epoxy fiberglass lamination very well.

Don’t forget to vent EPS foam surfboards, this is a must for all densities of this foam or else the trapped air in between the beads of the foam will expand and push on the epoxy fiberglass “skin” of the surfboard and WILL cause it to delaminate.

XPS foam is the insulation foam that you find as blue or pink usually, it’s not beaded like EPS foam but it’s very rigid as well.  It shapes really nice and can be sanded very smooth but this is not recommended as epoxy fiberglass lamination doesn’t “stick” to it as well.  Having said that I have no problems using XPS foam and have made some really great boards with it.  The foam does not need to be sealed since there is no air gaps since there are no beads and therefore does not need to be vented.  The typical insulation sheets you can find is a perfect density for a surfboard.

Since the closure of Clark foam in the 00’s, surfboard manufacturers started to experimenting more with different types of foams and more innovation has been a result of it using both EPS and XPS foams.

Remember to only use epoxy resins on these types of foams, using polyester resin will melt EPS and XPS foams.

Do you think I can make a surfboard in my apartment?  I don’t have access to any workspace or outdoor space.

Absolutely but because as making a surfboard is a toxic endeavour (see the question around PPE), make sure you have a space you can vent.  Sanding will make a ton of dust so be nice to your neighbours and make sure to seal your work space well as you don’t want to contaminate your living space and venting it outside might contaminate other people’s property.

Also, planning, sanding etc can make all kinds of noise so work when your neighbours aren’t home or sleeping.

Can I make a surfboard without a stringer?

Yes, but it depends.  A stringer provides strength and yet gives a surfboard stiffness yet provides “give” or flex or liveliness that surfers like.  Although that might be more out of traditionalism or what surfers are used to (just an opinion, not fact).  This is when the stringer is applied in a polyurethane surfboard, for EPS foam it’s slightly different.
 
EPS foam is much stronger than traditional polyurethane foam, in that it’s rigid and stiff.  When glassed with epoxy resin, an EPS surfboard is far more stronger than a traditional surfboard and doesn’t need a stringer.  Now of course if you are making a super thin performance board it might make sense to add a stringer even to an EPS surfboard, there are limits.  For thicker EPS boards it’s really not necessary to add a stringer, of course that depends on the glassing schedule, less glass probably would need a stringer, more glass would not need a stringer.
 
In the last few years we are seeing carbon fiber being used in lieu of a wooden stringer with EPS performance boards.

What do carbon fiber patches or stringers do?

Carbon fiber helps stiffen and strengthen areas of a surfboard to give certain flex characteristics.  Can be used to substitute a stringer to help give a stiffness.  You can sometimes see tail patches on the tail of a surfboard that helps strengthen the thinner areas.  Used in different areas on the deck or bottom of a surfboard can yield interesting results.

What happens if you don’t use fiberglass cloth? Are there any alternatives to that?

There really isn’t any great substitutes for fiberglass cloth, there has been some experimentation with newer types of cloths that are made from bamboo and there are some newer “space age” laminates but I personally haven’t used any of them.  There are cloths that you can use in combination with fiberglass to make a composite sandwich to give certain properties (impact resistance, stiffer sections) but for the main part of a surfboard, fiberglass is still the best IMO.

Fiberglass cloth is common, strong and inexpensive, there is a reason why it’s been used for boats, showers enclosures and surfboards for decades.

My glosscoat comes out cloudy, what is going on?

This is most likely due to tiny air bubbles being trapped in the resin mixture.  When mixing epoxy it’s important not to mix it like cake batter.  Don’t whip air into it, use deliberate smooth slow circular motions (don’t forget to scrape down the sides), the faster and more vigorous you mix it the more the epoxy will trap little air bubbles in it.  Also the more layers of epoxy you apply and the darker the color of the surfboard the more you will see this cloudy finish. 

It’s tempting to use a vacuum chamber to pull the air out of the mixture but typically the epoxies we are using for surfboard building start to harden quickly, especially if it is left in the pot.  It’s best to just mix and start glossing the surfboard.

How do I apply a proper tape dam at the tail of the surfboard?

To apply a nice tape dam for the tail bottom part of the surfboard is fairly easy once I knew what I was doing wrong.  Key is not to use too much masking tape, meaning don’t have too much above the bottom of the surfboard bottom.  All you need is about 1/4″ or even 3/16″ above the bottom.  Using too much tape causes the tape to fold in on the bottom of the board and keeps the epoxy from creating a nice edge.  You want just enough resin to pool in the tail area so you can later sand a nice sharp edge.

Once applied I like to use my fingers and gently push back the whole perimeter of the tape dam, just to make sure it holds it shape.  I like using 3M general purpose masking tape or another high quality tape, don’t use the cheap stuff, it’s no good.

What kind of PPE do I need when building a surfboard?

 This is what I use:

• Respirator – Making surfboards is a dusty, dirty and potentially toxic process, you only have one set of lungs protect them!  Wear it when sanding or working with resins.
• Eye protection – Again you only have one set of eyes, grinding and sanding can throw up all kinds of stuff that you don’t want in your eyes.
• Nitrile or latex gloves – Working with epoxy resins is messy and is a potential skin sensitizer, protect your skin!  Also sanding fiberglass can really irritate your skin, especially around your hands.
• Coveralls or garbage bag – Coveralls can keep resins and sanding dust off you.  I typically just cut holes in a garbage bag now and wear that, cheap and effective.