home made fibreglass fins

[spear4food]

Has anyone tried to make their own fibreglass blades, how hard can it be?

[alexrom1207]

I start out thinking that prior to every DIY project I start. 3 hours of wasted time later I realize it was a hell of a lot harder than I thought. But it probably would be plausible to make a pair of blades (although some may be tapered etc...which could make things difficult)

[marginatus]

use the search function i think someone posted pics of the process

[armandozx]

indeed, some one actually made them but I don't think he gave out the secret because he thought every one was going to leach off his work. But IMO I think they where to thin and probably did not work well.

[Lockedin]

Perhaps making blades for existing footpockets. I used to shape and glass my own surfboards. I would think that the hard thing would be preventing stress cracks, resulting from the constant flex and recoil. I have OMER footpockets. Has anyone else tried (OMER or otherwise)?

Gee, thanks guys! Yet another Wife annoying project for me!

[foxfish]

I am always making one off moulds, presses, plugs etc for various fiberglass components.
I would think - unless you have access to actually specifications you will have to do some experimentation with thicknesses, layers & resin - matt ratios etc.
If you have the time & Patience I think it would be quite possible to make the blades. I would simply lay up a few pieces of 1oz matt & press them inbetween a home made jig using weights to compress the fibers.
Then you will have a base to work from, to cut out the shape & test for flex.

[Jonny250]

If you want to make the blades and fit them to existing foot pockets then it shouldn't be too hard; the hardest part is probably getting the angle between the close end and the main part of the blade (my omers have an angle of roughly 7 degrees at the footpocket connection). cutting the profile to fit the pocket should be ok.
Best way would be to make a bottom mould on a flat panel using filler or plasticene, covered with a sheet of polythene. Lay the fibreglass over this, then vacuum bag the lot down. i think vacuum bagging would be important as you dont want a resin-rich blade or it will crack. You can use a layer of peel-ply to further reduce resin content.
ideally you dont want to use chopped mat but use biaxial plies in 0/90 and +-45 directions, or even a triaxial mat so that there is less resin, more fibre. thickness required can be done by using an 'equivalent stiffess' calculation and equating the laminate to a 'known' blade. some difficulty with this is that most blades aren't flat, so stiffness becomes a function of geometry as well as laminate thickness.
best way would be to make the bottom mould off an existing blade and scale the stiffness of the materials for thickness and lay-up accordingly (try it, learn and adjust).
Not too hard if you already have the materials but defo easier to just buy!
No doubt there's plenty of other ways to do it too...

[spear4food]

Hi Guys, I have a pair of water way power blades that i was thinking of using as a model. I'm thinking the fibre wouldn't be the problem nor the layering but the secret would be in the resin, that has to be water proof and be able to take the flexing. Also if the vacuuming process is necessary then that starts to get messy.

[Jonny250]

I dont think vacuum process is essential, but defo a good idea for a better quality product = and not that hard really - you just need different kit (it's actaually a lot less messy in the literal sense).
The following link gives the concept, but makes it look a bit complicated - doesn't need to be.
NETCOMPOSITES | Guide To Composites | Vacuum Bagging
You can use a hoover for the vacuum, but dont suck directly, you need a pot in betwen to drain any excess resin.

You may want to look into resin additives to give more flexure.
most resin will be waterproof over the life of the blade, epoxy or vinylester is better and have better mechanical properties than polyester, but you pays your money...

[alexrom1207]

Just an idea but adding latex to the resin may make it more flexible. Contractors all add latex to the mortar and grout when they do tile work so that it will have some flex and not crack. I figure this will probably work just as well for resin (that is if you can find a thin enough latex so it will keep the resin really fluid)

[hteas]

Here is a link to someone who has been making his own blades. Check out the photos. His contact is at the bottom if you want to contact him.Personally I'm sticking with my SpecialFins Bluewater Specials .

Palmes en fibre maison

[spear4food]

I have e.mailed an epoxy manufacturer to ask if he knew any resins that would suit and he is sending me a sample but i don't think he has had any experience on fin making That link looks promising

[NiallFlinn]

Originally Posted by alexrom1207

Just an idea but adding latex to the resin may make it more flexible. Contractors all add latex to the mortar and grout when they do tile work so that it will have some flex and not crack. I figure this will probably work just as well for resin (that is if you can find a thin enough latex so it will keep the resin really fluid)

I've never built any fins, but I used to experiment a little with building things from fibreglass and carbon fibre composites in my teens, and I want to point out that this will not "work just as well for resin". Mortar and tile grout are both water based cements, while plastic resin (polyester or epoxy) is built around totally different chemistry. Randomly adding water-based latex to it will result in a horrible sticky mess.

Niall

[Lockedin]

In case others are randomly mixing: Polyester and Epoxy do not mix well, either. As a teen, I glassed boards for a shaper, and repaired them for extra money. I accidentaly tried to use polyester resin on an epoxy / polysterene board. It melted a hole through the board.

We did thin with acetone, use release films, and use less catalyst (1oz. resin : 5-6 drops catalyst - compared to 10-15 drops for a "hot coat") to acheive a nice gloss, and we felt that a slow cook (full reaction appx. 24 hrs, but we could accelerate by heating) kept the finished product more pliable.

[spear4food]

Thanks for all your help. The sample materials never showed up and by what i can work out the costings would be too expensive compared to buying a pair ready made IE. waterway bi-fins and without the possible error factor. I am thinking of getting the stiffness #3's does anyone have experience with these fins please?