An Intro to Surfboard Foam

An Intro to Surfboard Foam

Surfblanks Australia has been making surfboard foam since 1968 and Surfblanks South Africa since 1989.   We are dedicated to producing the highest quality foam/stringer combinations. The density chart below offers great choices for lightness and strength. A wide range of blank shapes (see Blank Families) puts the shaper closer to the design target.

 

Many stringer choices coupled with functional rocker curves will allow for cutting edge surfboard design that is and always has been the core feature of the custom surfboard industry.

Note: Surfblanks foams are formulated for the surfer first, and the shaper second. It would be very easy (and cynical) to tilt the formula in the shaper’s favour, however doing so would halve the life of the finished board.

Experienced shapers have the answer to strong foam in their cutting quiver.

Tungsten carbide grit barrels for Hitachi and Makita planers are becoming widely available around the world. The grit barrel advantage means no blade sharpening required – ever! Sharp, conventional planer blades work well with Surfblanks foam as do sharp surforms and sand paper.

Many fast shaping foams have a dead feel in the water. A pleasing feature with Surfblanks foams is that they make a very lively feeling surfboard.

This liveliness can be attributed to memory, or ‘spring back’ and a specifically designed density gradient. The core of a Surfblank is somewhat lighter and less dense than the outer skins.

Composite surfboard manufacturers (EPS/Epoxy/WoodVeneer/Cloth/sandwich) spend endless time and money trying to achieve this very basic element which is incorporated into every Surfblank.

Blanks that have a ‘dead feel’ in the water are usually those that are made on ‘old technology’. Off the shelf foam technology supplied by large chemical companies usually dictates that a surfboard foam blank will be soft on the outside and hard and dense on the inside, particularly at the core. Surfboards made from such foam will have very little ‘life’ in the water and are more prone to clean (brittle) snaps when they break.

It is fair to say that Surfblanks would have made foam as is described in the above paragraph for the first ten to fifteen years of the company’s life. Since that time the Surfblanks formula has developed year by year to the point where it bears little resemblance to the 1960′s, 1970′s,and early 1980′s formulae.

The current formula which was last modified in July 2010 has allowed Surfblanks to increase and enhance its density range. At first glance it’s hard to imagine that all of these blank weights could be useful. The fact is that amongst all these options there is a blank weight that will allow a shaper to achieve something unique that is in his/her head.

Density Chart
Pink – -32% add 20% to price list

Yellow – -24% add 20% to price list

Green – -16%

Blue – -8%

Red – Base Density -
Once a very popular density, now considered way too strong due to new Super Strong formula.

Density colour name/date of introduction/Surfblanks original name.

Pink Foam 2008 - 1.82 lb cu ft developed into an impressive (very) core in 2010 when the Super Strong formula emerged. 2013 sees steady sales growth of this foam as makers realise its potential. Surfblanks Yellow has never been matched for weight/strength anywhere in the world by any surfboard foam maker. It’s easy to imagine how special Surfblanks Pink foam is. Primarily paddle speed is greatly enhanced, then maneuver response is found to be awesome. No EPS/epoxy hassles with this foam. Add 20% to listed price.

Yellow Foam 1998 (Elektrafoam) - 1.98 lb cu ft (approx minimum, without stringer) – Has developed substantially since 2002. Cell size is down and compression strength is up. As of 2006 Surfblanks has been making increasing numbers of blanks from this foam. Blanks made from this foam are always glued with yellow glue for identification purposes. In 2007, formulation changes made Yellow Foam easier to produce. Add 20% to listed price.

EPS/Epoxy users are turning to Yellow Foam since it avoids all the preparation required for an EPS blank. Finished weights are on par if not better. The buckle and crush strength of Yellow Foam dramatically exceeds that of EPS at a similar weight.

Green Foam 1990 (Hyperlight) - 2.14 lb cu ft (approx) – Widely used for team rider’s shortboards, Green will produce what might be considered the lightest urethane foam surfboard on the planet. The popularity of this foam continues to grow even though the life of the finished surfboard may be short. It is rarely used in longboards. Always glued with green glue for identification.

Blue Foam 1985 (Megalight) - 2.31 lb cu ft (approx) – The ‘all time’ favourite foam for shortboards. High paddling buoyancy and lively surfing response on a wave make this foam the choice of hard core to recreational surfers. Needs a really good glass job so as not to dent.

Red Foam 1972 (Ultralight) - 2.49 lb cu ft (approx) – This is the Median Density (base) foam when all blanks made by Surfblanks Australia are averaged out for density choice by all customers. It is desirable that blanks for shaping machines be made from this foam where cutting will significantly reduce the original blank volume. Red Foam in shortboards is considered excellent for compression strength and once glassed is approximately equivalent in weight to – 1.Clark Supergreen, 2.Burford Green, 3.Bennett Green.

This comparison is offered as a guide for first time Surfblanks users. Red Foam in longboards is considered very light and buoyant. There are cutting edge manufacturers who make most of their shortboards from Blue Foam and their team rider boards from Green Foam.

Foam Blank Type Abbreviations

SB – Shortboard

MM – Mini Mal

KF – Kneeboard Fish

FF – Funboard Fish

LB – Longboard

GB – Gun

These abbreviations will appear throughout the Surfblanks Price List.

STRENGTH ENHANCEMENTS
Whatever density the shaper chooses, it is the glass job that ultimately determines the strength and durability of the finished surfboard.

The glass job is critical on a longboard due to foam thickness versus length of the shape (very thin for length).

The more rail laminations of cloth layers the stronger the longboard (or any surfboard) is. Zipper cut laps (halfway around the rail) are a no/no as they provide less than the full strength which is available from the rail. Warped weave cloth (more long strands) is highly desirable for snap strength. S glass beats most every cloth for ease of use, strength and appearance. S glass has an advantage of 50% in tensile and 25% in compressive strength.

Ultra violet light cured polyester resin has proven a great strength enhancer for glass jobs. As opposed to MEKP cured polyester, the more sunlight UV cured polyester gets exposed to the stronger it becomes, up to a point. MEKP catalysis in polyesters is very hit and miss. Ambient temperature plays a negative part (too little, too much MEKP required) in crosslinking initiation of the styrene monomer and polyester backbone. A controlled temperature environment for MEKP cured polyester is very desirable.