Lost foam hollow wakesurf board construction

You know it’s funny, we’ve been doing several projects all at once, and we tend to focus on one or the other for our writeups and then all of a sudden we realize, oh wait! That one’s almost finished and we haven’t written anything in two weeks! We’re going to go back and revisit the lost foam hollow wakesurf board we started several weeks ago. To bring everyone up to speed the plan was to take a section of crappy eps foam, shape it, glue top and bottom skins to it and then melt the interior foam to make it a hollow wakesurf board.

In the last post we documented the materials that we would be using, they included carbon fiber, an aramid honeycomb and fiberglass. The honeycomb will be used in the top and bottom skin. The fiberglass will be the outermost external layer. Carbon fiber will be used for all internal layers.

For the bottom of this hollow wakesurf board we are going to make a prefabbed external skin composed of fiberglass and carbon fiber. If you’ve got any of a number of popular skimboards, you may have noticed that the color or gloss on the bottom of the board is significantly better than the same item on the deck. The effects of gravity and a fixed surface can create that beautiful bottom and less beautiful top. Of course, an inverted wakesurf board rocker mold for the deck would create the same beautiful colors and gloss, if the bottom skin were prefabbed!

We’ll start this process with some scrape fiberglass, this is 4 oz that we have saved from a previous project, hence the weird offcut like shape.

Working our way UP from bottom to top in the laminate stack is a piece of carbon fiber. We haven’t tried to lay this piece down on a bias, but that will obviously need to be done for the successive layers.

It’s a little hard to see, but we won’t be lapping the bottom of the board to the deck, instead, we’ll just create a glossed bottom surface that will be epoxied to the core…well actually the honeycomb bottom skin. So we trim the fiberglass and carbon fiber to the exact dimensions of the core.

We need to give a little explanation as to what’s going on here and why we did what we did! First the picture as an aid for the ensuing discussion.

It’s hard to see, but from the top down, the stack includes the honeycomb, carbon fiber and fiberglass. All of them are laid up on top of a mylar sheet that rests on our Flyboy Wakesurf board rrocker table that includes a concave shape. We want to affix the honeycomb here, because being hollow, if we glue it with epoxy draining from the top down, there would be excess epoxy accumulating in the empty cells. This sequence, we hope, will allow us to prevent any build up of excess epoxy in the hollow honeycomb cells and give us some rigidity for attaching to the bottom of the wakesurf board.

Here is the stack all wet out and ready for bagging. We slide the entire rocker bed into a vacuum bag and pull a vacuum until the epoxy has cured!

That gives you an idea as to how we are planning the bottom skin, two layers of carbon fiber sandwiching a honeycomb, although we haven’t shown the second layer of carbon fiber yet, and the exterior fiberglass. That skin will be prefabricated for later attachment to the interior core of the wakesurf board.

Thanks so much for following along!

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