fiberglass sheet for monofin blades? mono-fab video

[neurodoc]

I wonder if anyone can help me figure out what type/brand of fiberglass sheet is used to make monofin blades, of the type where the layering is done by scoring and peeling off layers of glass. There is a series of videos now on YouTube, posted by Sergei Kutikov in Talinn (Estonia I believe?) that shows this process:
[ame=http://www.youtube.com/watch?v=U1cd-7YJCq4&feature=fvst]YouTube - How to make a monofin 1 -FIBERGLASS - .avi[/ame]
which is the first video; there are seven more I believe. This seems to be a straightforward way to produce a tapered blade, with many options to tailor the response of the blade. Is the glass a special kind? I've never tried to peel layers off like that, so maybe it is just regular laminated sheet? Anyway, I thought the video series is worth sharing here-either for do-it-yourselfers, or those interested in one fabrication process. It does take an awful lot of steps! no wonder the fins cost what they do.

 

[Bill]

'I wonder if anyone can help me figure out what type/brand of fiberglass sheet'

When I asked this question, I was told that it is called printed circuit board. I have seen it in 1/32 and 1/16 inches but it had copper on one or both sides. I thought maybe they have a spray on process and it comes without copper but I didn't follow up because you would need to do a lot of careful sanding or use a milling machine.

 

[neurodoc]

McMaster-Carr has Garolite, which is a circuit-board type of fiberglass but not copper coated...I wonder if that would be usable. Anybody tried it?

 

[ReefTroll]

If it is indeed formed the same way as a circuit board then it'll be rock hard and very brittle
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[neurodoc]

ReefTroll I had the same thought...must be some other type of fiberglass because the video shows it being quite flexible. If circuit boards were that flexible electronics would be much tougher ;-)

 

[REVAN]

Peeling the laminates is actually a really cheesy method for creating a tapered laminate. I have done it before and unless the panel is resin rich (something you don't want in a monofin blade), it is really difficult to do without damaging the fibers you are trying to keep intact. Resin rich panels will be brittle and have poor energy return from deformation compared to a panel with the appropriate ratio of glass fiber to matrix. This may be why Bill had been told to use the circuit board panel. They are resin rich and brittle which makes them more easy to peel.

If you want to make a monofin, I strongly suggest you lay up your own laminates. For a one off project it is probably going to be less work, although you will have to spend some time getting all the ingredients together to do the job. However, the benefits are numerous and well worth it in my opinion.

For one, you can make your panel non-flat to build angle into your blade without having to build up huge foot pockets to integrate the blade. Most importantly, you can have seamless tapering of the laminates. You can select the types of materials that go into you fin blade and have full control over the ratios and quality of the layup.

In addition to the materials you want to lay up, you will need a caul plate to lay the material up on (a flat sheet of sturdy aluminum will work, but I suggest putting a 30 degree bend in it for making a freediving monofin). You will also need plastic bagging material (I like polyetheline for low temperature resin cures), tacky tape, peel-ply, bleeder/breather cloth, and some mold release wax and a vacuum system. Harbor Freight has a cheap venturi-style vacuum system that runs off an air compressor for about $14 that will work well for this application if you have an air compressor.

Usually you can buy all the materials you need at a composite supply shop, but if you don't have one near you you can order online from AIRTECH International, INC.. Let me know if you need advice on how to proceed if you decide to go this rout.

 

[neurodoc]

Ron, as usual you have great information. What you've explained does make a lot of sense-peeling the laminates would compromise the fibers as well as the integrity of the seal between the laminations. I have been thinking about taking the dive into laminating my own fins, and appreciate the offer of information. I may take you up on that!

 

[ReefTroll]

You can get flexible circuit boards but theyre definitely not fiberglass!
Mine you, circuit boards are multi layer, maybe they talk about individual layers?
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