Tech Talk: The ideal board weight ratio

26.08.2024

What’s up everyone? Welcome back to another Appletree Surfboards Tech Talk. Today we’re going to have a bit of a technical one because we’re going to talk about board weight again. Now we’ve done a few videos about board weight and what it does for your riding in both kiting, surf foiling and wing foiling. But what we haven’t really explained is how the Appletree boards are exactly constructed and how it works with the weight, because that’s quite a different story altogether.

What determines board weight?

In general, when you’re making a board, the final weight of the board is determined by three factors:

One is the fiberglass or the carbon fiber that’s around the board, so your fiber matrix.
Then the second one is your resin, in our case, pure epoxy resin and the amount that you use.
Finally, there’s of course the foam weight.

These three factors determine how heavy and also how strong your boards are. In our construction that we’ve explained a couple of times, we’re using this vacuum infusion process. And what that does, it actually creates the ideal ratio between fiber and resin in your board.

What is the ideal fiber and resin ratio?

Why do you need this ideal fiber and resin ratio? It’s important for the fibers to get their maximum strength. You want to get the maximum strength out of the fibers. There’s an ideal ratio of the amount of epoxy resin that you have to get into that fiber. And it’s actually quite a low amount of resin. To make the fiber as strong as it can potentially be.

And the only way to get this is through vacuum infusion or through a prepreg process. Now a prepreg process is not really possible on boards, but resin infusion turns out it is. It is something that no other brand is currently using in the market because it’s extremely hard process to do.

But we’ve at Appletree Surfboards, we’ve cracked this the code to doing vacuum infusion a number of years ago. And nowadays we do all our boards with this vacuum infusion tech. So the ideal ratio between fiber and resin is super important. And this infusion tech is the only way to get there.

The ideal board weight ratio: light and strong

In our smaller boards, we think that we’ve cracked the code for making a board super light and super strong. It’s maybe not the lightest board in the market, but pound for pound, the strength you’re going to get from these boards is so much higher than anything else. And also the strength, especially on the rails and the tails and the fin boxes are locked in in such a way that they basically never break out.

This is not only due to the fiber and the resin, but also due to the foam that we use. We use this waterproof, super high density foam. That gives the boards its inherent strength and also it’s completely waterproof. So if you do get a small ding in your board, you don’t actually need to repair it straight away because water can’t absorb into the foam guaranteed.

XPS foam is slightly heavier

Now there is one small downside to this waterproof foam and that is that it is slightly heavier to your industry standard EPS foam. This is a downside that we really have thought long and hard about if it’s something that we do accept.

But all the testing that we’ve done, this foam feels better. It feels more lively. And it stays lively years after the board has been constructed. It will stay nice and fresh. Plus the strength is so high that in the end we decided to stick with this foam in all of our production boards.

Low weight shell

On smaller surfboards like this kite board here, that’s only an 18 and a half liter one, there’s no problem with the foam weight. It’s still one of the lightest boards you can get. If you go into the foil boards and especially into the bigger ones, if you go over 70, 80 liters, somewhere roughly around that point, we lose the advantage of having a really low weight shell.

So low weight epoxy, low weight fiber, and the weight of the foam slowly starts to get into play a bit more, which is of course definitely a downside. We’re always trying to evolve and trying to find new ways to combat this or different foams. But in general, that’s sort of where the tipping point is.

If we would make a board 150 liters, for instance, it would really be too heavy and there is better foams out there. But because we focus on making high performance boards for riders that know what they’re doing and riders that want to have the highest quality, they generally don’t want a board that’s over 100 liters or over 90 liters.

So in our case, it is actually still a very big positive, especially for the kite boards and the normal surfboards and the surf foil boards. The boards are just super light and super responsive and super stiff. So you get all the advantages.

Average board weights

At Appletree Surfboards, we try to communicate the average weights of our boards. For most of the boards, you will find them online. There’s always a bit of a deviation because of the custom production process. We accept the 5 percent up and down from this. If you want to know specific weights for the board that you were after, shoot us an email and we are always able to help you out and give you an estimate.