HOW TO CHOOSE THE RIGHT BLANK FOR YOUR SURFBOARD SHAPE
EPS foam blanks have been used in surfboard construction since the early 1980's but is quickly gaining popularity since advancements in foam technology has made EPS easier to work with and producing lighter, stronger boards. Surfboards shaped with EPS and glassed with Epoxy Resin have proven to have superior strength/weight ratios to PU/Polyester boards (about 3X stronger). EPS boards have been particularly popular for small-wave boards, where light-weight is important, and also are gaining popularity in big-wave guns, and performance longboards, and high performance shortboards, where strength/weight ratio is important. EPS foam is very durable and much more impact resistant than PU foam which means less dings and your board will keep it's lively flex and rebound feel for many years.
EPS blanks have a consistent density throughout the blank, so there is no worry of over-shaping the blank and exposing a weaker inner core. Most beginner shapers choose EPS blanks, as they are easiest to shape and produce a durable but still lightweight board. Greenlight's Engineered EPS blanks are the best quality and most consistent foam on the market. We recommend shaping EPS with our Greenlight Tool pack which we designed to be the most effective and easiest way to shape surfboards.
You can purchase a Greenlight Stock EPS blank in a variety of sizes and styles. We've categorized each type of blank in a "Series" so you can easily choose the right style blank for the type of board you're building (Fish, High Performance Shortboard, Longboard, Wakesurf, etc.)
We also offer a custom close tolerance blank cutting service which greatly reduces the amount of labor and dust created in your workspace while providing a perfectly cut outline, foil, and rocker based on your design. All you have to do is shape the rails and bottom contours. Combining technology and soulful hand shaping it the smartest way to shape in our opinion and definitely provides the best results.
One last comment of EPS foam, it MUST be glassed with epoxy resin! Polyester resin will melt the foam! Please do not make this mistake.
PU blanks have been the go-to core for the surfboard industry since the 60s. You can laminate them with epoxy or polyester resin. PU blanks are typically more dense and heavier than EPS blanks. Most PU blanks have a density of 3 lbs per cubic foot, while Greenlight EPS blanks are a specially engineered 2# per cubic foot density. PU foam shapes nicely and takes paint well for artwork.
Another unique characteristic of PU blanks is that they are denser in the “outer skin” than the “inner core.” When shaping PU, most shapers use “close tolerance” blanks, where they don’t have to shape deeper than the outer skin to preserve the most durable component of the blank. If you shape too far into a PU blank, the soft inner core will be exposed and your board is more likely to get pressure dings and delaminations in these areas. For this reason, EPS blanks are usually a safer, and stronger bet for beginner shapers.
Boards shaped with polyurethane foam will have a shorter lifespan and will deteriorate over time, losing it's flex and rebound characteristics and eventually break or buckle. But they surf nicely...
PU surfboard blanks can be glassed with either Polyester resin or Epoxy resin, with epoxy resin being a more popular choice for a longer lasting surfboard.
CHOOSING THE RIGHT SIZE BLANK
Once you have decided on PU or EPS, you need to choose the appropriately sized blank for your planned design. The three things you need to consider are:
- Rocker Profile
When choosing a blank length, in general, the blank should be at least 1/4" inch longer, but not more than 6 inches longer than your intended final shape. Greenlight's Engineered EPS blanks are designed 1/4" longer than the nominal length so you can fit the board you want in the blank (provided the rocker is what you're aiming for - more on that below). Too short and you won’t be able to fit your shape on the blank, too long and you will have trouble getting the correct rocker shaped. So if you are going to shape a 6’0” fish, make sure you start with a blank that is at least 6’0 1/4"+ and not longer than 6’6”. Although you can shape a 6'0" board from a 6'0" blank with no room for rocker adjustment, or a 6'0" from a 9'3" blank and cut a few feet off either (or both ends). Remember your surfboard is sitting somewhere inside the blank, it's your job to bring it out.
When choosing a blank width, you need to primarily make sure that your blank is wide enough in all key dimensions: 12” from the nose, in the wide point, and 12” from the tail. Greenlight stock EPS blanks come in rectangular outlines that are 24" wide, so width isn’t an issue, but other blanks usually come in more compact “shortboard” profiles where the nose and tail are relatively narrow, or “fish/hybrid/longboard” profiles, where the nose and tail are wider and more suitable for these shapes. So if you’re making a short fish, make sure the blank is wide enough in the nose/tail area. Many “shortboard” blanks won’t work for fish shapes.
Finally, you need to make sure you can carve out the appropriate rocker from your blank. While some blank manufacturers offer custom rockers, as a beginner, you will most likely be choosing a “stock” rocker profile for your first board. Stock rockers usually fall in two categories: more curvy, shortboard rockers, or flatter fish rockers. The shortboard rockers usually have higher, thinner nose and tail curve, while the fish rockers have lower, thicker nose and tail curves.
Greenlight has made surfboard shaping easier and more accurate by offering a Custom EPS Blank Cutting Service. Design your blank with free software and all you have to do is shape the rails and bottom contours (if any). We take care of the critical outline and rocker shape from your design! If you have designed your board in the AKUShaper program, you will have all of the measurements needed to determine if a blank is suitable for your design: thickness in the center, nose, and tail; plus rocker in the nose and tail area. Every blank maker has a spec sheet for each blank which identifies the key measurements of the blank. If you have not designed with a CAD program, you just need to make sure you choose a “shortboard” rocker for making a shortboard or a “fish rocker” for making any type of low-rocker board. When in doubt, the crew at Greenlight can always steer you toward the most appropriate blank for your intended design.