Well with most of the WWSC winding down, it’s time to get back to the work at hand of shaping wakesurf boards. We want to introduce a topic that we’ll be playing with a bunch during the off season and that is resin infusion. But before we delve into that topic, lets talk briefly about another concept that we are calling a triple density core or blank. Principally it has two interior foams, the one on the top is slightly more dense, and also a little more stiff. The deck side of the core is also thinner, well that’s a misnormer, the foam used on the deck side is only about 1/2″ while the foam on the bottom is about 1 inch thick. The bottom of the core is a lighter weight EPS foam and the deck side is a 1.8 pound density XPS. Just so you can get a visual, here is what the two pieces of foam look like before being glued together.
The XPS foam on the deck side is the pink stuff and the white on the bottom is EPS. What we haven’t introduced is the skins on the exterior which will be a third layer in the triple density core, significantly higher than the other two foams and those will make up the triple density core. Now our plan is to basically shape the core material – concave, rocker, outline and rails and then laminate the two pieces together with a layer of fiberglass in between. The pattern will be to lap the rails in different directions. That is one going up and the next going down. There should be three rail laps just within the core itself.
Now if you’ve followed the Flyboy Wakesurf blog for any length of time you know that we aren’t a big fan of XPS and we stil aren’t. It is copolymorized with polyethelene which is the plastic sheeting we use when we don’t want resin to stick to it! We are hoping that enclosing the XPS inside of the skins and not outside, that there will be minimal opportunity for a delamination. Time will tell!
That now leads us into the concept of resin infusion. In short, rather than laying up the various reinforcements wet, the reinforcements are placed onto the project core dry, then a vacuum is pulled and the reinforcements positioned properly. Once the builder is satisfied, a spigot is opened and the infusion resin is allowed to be drawn into the vacuum bag or mold, by the vacuum pressure. Once the reinforcements are completely wet, the spigot is closed and the vacuum continues to pull excess resin out of the project.
Resin infusion has a few advantages, first is basically unlimted time to get the reinforcements poistioned. Second vortually no VOC in the air. Third is that the reinforcements are consolidated or compressed against the project before being wet out, so the they are thinner. Maybe only a tiny difference, but it reduces the amount of resin that is used, making for a stronger and lighter final part.
It also has some disadvantages, one is that it’s way more complicated and once the spigot is open, there is NO turning back. Also, there are lots more consumable supplies used so it winds up being more expensive and also requires MACH PRESSURE, so a new pump and this also limits the type of project that can be made using infusion. Lightweight low density foam would crush flat under the pressure needed for resin infusion.
However despite the drawbacks we believe that the process of infusion, and no longer having to sand rail laps! has advantages. Now you may be wondering how can we do the infusion without using a mold and that would be an excellent question, that we’ll not address right now! So there!
So thanks so much for following along, we appreciate your time and attention!