Jun 07

Molding fins

We’re going to be experimenting with some fin construction and we wanted to share that with everyone. We’re going to be using various fin molding techniques, that we can do within our limited tooling capacity. We won’t be able to do things like injection molding, but we can do expansion and compression molding.

We’ll jump ahead so that you can get an idea of the finished product which should help you visualize what we are doing! So James Walker rides a Futures Fin referred to as the 3/2/1. It is out of production, which is sad, because it is one of the best fins for wakesurf use. That also set us into this replacement mode. We’ve designed the Flyboy Wakesurf board for James based upon his favorite fin and so not being able to replace it at wholesale was disheartening!

We decided we’d start work on creating a DIY replacement and at the same time, build in some advances in construction. Most likely you’ve seen these light weight “clear hex” surfboard fins from manufacturers like Futures and FCS. Here is a picture of a clear hex 3/2/1 knock off (you can’t buy these, these are a Flyboy Exclusive product) and then behind that a natural composite 3/2/1 (which is a fancy name for plastic).


That material in the middle of the clear hex fin is responsible for making them significantly lighter. That material is Soric, manufactured by a company name Lantor in the Netherlands.

In this picture you can see the clear hex fin and then behind that the material that is used, Lantor Soric. Soric is a nonwoven polyester fabric with the plastic hexagonal cells, those cells give it that distinctive hex appearance.


Soric was developed for resin infusion, allowing resin to be spread quickly without compressing the material under the pressure from the infusion process. The cells don’t absorb resin and so displace about 30% of the weight compared to regular glass lamination or the “natural composite” full plastic construction. Now you’d guess that polyester, like a cheap suit, would compress with any sort of pressure and it DOES!  The hexagonal channels are crazy stiff and strong and are basically impervious to any sort of pressure within a technique used for molding fins.

Now the next paragrapgh is going to be a bit confusing, mostly because of the talking heads and the bloated egos out there. You’ve no doubt heard of compression molded wakesurf boards and equate that to cheap and heavy products. The folks that spew that vile garbage have never molded anything in their lives and we’re sure prance around their bathroom smiling at themselves in the mirror.

Compression molding is a process and nothing more. There are a gazillion flavors of molding, everything from expansion compression molding to light resin transfer molding and everything in between. Compression molding is used, in any number of super light weight products, just as these fins were manufactured with injection molding techniques, the Soric based fins are significantly lighter than the natural based fins. That doesn’t make injection molding responsible for heavy and cheap products, it’s just a process.

Typically compression molding is used to create large quantities of a single product. It’s fast and realtively inexpensive. However, the manufacturer can then say – make it ridiculously durable and as cheap as possible, which is NOT a process requirement, but a manufacturing decision for profit and pricing purposes.

So as we walk you through this process, ignore the yokels that have no idea what they are talking about. If you haven’t seen them pry open a mold, it’s safe to say they are merely repeating some story that someone else told them and never did any fact checking at all. We’ll start calling them “Prancers” for their mirror prancing routines.  Those folks are ONLY interested in their egos, not providing useful information.

As we walk through his process, we’ll be undoing a LOT of misinformation that gets spewed by those prancers, so we’ll have to ask you to bear with us, but in the end you’ll be so much better informed and very possibly be in a position to start making your own fin sets. We’ll save fin theory for a different set of posts, instead this will be focused on several different construction techniques. If you’re been thinking of different fin designs that might help you land cool new wakesurf tricks, you’ll be able to make those ideas a reality.

So first off, compression molding does not equal cheap and heavy, manfucaturers CHOOSE to make compression molded products cheap and heavy.  Compression molding can and is used to make significantly lighter products and even very finely detailed products like lens.  Any molding process where the quantity of material can be determined prior to manufacture, can use compression molding and it is the material choice that determines the final weight and also most likely cost.  So, compression molding can make heavy and cheap, but can also make super light and realtively expensive and compleicated parts.

Thanks so much for following along, we really appreciate it.

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