Hi, Im repairing an old yater HP for a friend who snapped his glassed fin. I noticed that the fin that snapped was a center fin glassed into the board as a side fin… lol. But due to my friend not having money he cant afford to get a whole set and of course you can’t buy singles. So I’m considering cutting the tabs off an old right side fcs fin thats plastic/composite and using that to glass. I’ve done it a few times with success using glass fins, but am worried that the PU resin wont stick or will just peel off with time. I figured giving it a good sanding before would work but I’m in need of Swaylocks infinite wisdom. Has anyone tried this?
Take this with a grain of salt because its not your intended use. The cheap set of FCS plastic fins I use for setting boxes and plugs has tons of poly resin drips on them. The resin can be chipped off with a screwdriver/chisel, but it is reasonably difficult to do and the fins have the smooth finish. I would think that roughing up the surface with sandpaper and glassing the plastic fins on would be fine for a temporary fix.
That being said, making a fin isn’t especially difficult and can be done well with hand tools and arm power. A quickly shaped plywood/scrapwood fin would only be slightly more work and its a tested solution. There are even free tools like finfoil that make shaping the fin easy.
I completely forgot that was an option and I’ve honestly been wanting to give that a try anyway. Thanks for the push, I’ll give it a go!
Check out finfoil. It makes shaping fins dead simple. It was created by a sways brother and used by countless others. You just arrange and resize your chosen outline or import from blendingcurves. Change some parameters like thickness, fin type (symetrical, flat side, assymetrical), fin base if you want to. Print out a sheet and glue onto wood. Shape/sand to the lines on the sheet similarly to rail bands on surfboard. Sand, glass, polish, and ride.
I believe it was this forum where someone added some leading edge surface area to old school plastic composite FCS1 fins. I believe they just used thickened resin too, with no additional exterior glass. not sure the long term results.
I’ve been using epoxy on MrMik’s 3d printed PLA fins. Adhesion is OK. It very much helps that the PLA is somewhat porous. Using Denatured alcohol helps, as does increasing mechanical tooth via sharp sandpaper in an X pattern. Dull sandpaper might remove the shine but U shaped mountaintops and valleys do not compare to V shaped in terms of adhesion. I have micro drill bits in a dremel that I use at opposing angles to lock epoxy, or cyanoacrylate soaked fiberglass/carbon fiber to various substrates when lots of stress in involved which wants to separate teh glass from the substrate.
Ive seen several FCS1 finned boards whose owners glassed the FCS1 fins in place when one or more of the plugs broke and they could not easily replace the broken plugs and did not care about fin removal thereafter. Not sure how long they lasted.
I read something saying that when adhering epoxy to plastic to hit the prepped plastic( mechanical toothed degreased) with a torch immediately before applying resin to increasing bond strength.
Found it
source:
https://www.jamestowndistributors.com/userportal/document.do?docId=221
Note I am not sure the same applies with PE resin.
Good luck with however you choose to proceed
Umm, you could, but I might send Friend off on a mission to find a busted board with glassed in/on fins that are more or less the right size. He’s the one that wants this done cheap, he oughtta participate. Then, have at it to remove and clean up said fins and glass on the one that’s appropriate, reshaping said replacement as need be. A fin off a much shorter thruster is probably fine. Why?
I might have a look at the existing fin on the other side, if it’s also a center/foiled both sides fin, use the center thruster fin, if it isn’t, okay. use the appropriate side fin, in either case it’s probably more or less the same size.
By the way, if what you’re replacing was a repurposed center fin and the good one isn’t, you may want to check the alignment/camber/location and such, it’s a repair somebody else did and they may not have been that picky.
hope that’s of use
doc…
Thank you! I like the dremel x idea seems like it would be a solid bond
Sadly the center fin is the odd one out of the group. Thanks for the tip on allignment and the info I’ll have to get that measured out tomorrow.
Epoxy is a far better glue than poly so better use epoxy for this work.
Some molded thermoplastique can be glued other not realy. Scratch surface for mechanical bond, acetone wipe or flaming for chemical adhesion.
I did with these fins
The fins are better than the pic is
I used epoxy and ran a strip of CF tape along the front of the inside and into the area where it fits into the box then put a layer of cloth over that to sand the surface level (IIRC I layed it up and placed it against a glass plate coated with release agent)
Put fin rope around the edges and then 2 layers of 4 oz on the outside.
Had to make them fit into the box - of course - I thought of that ahead of time and narrowed the bottom where it fits in the box.
I actually have a mold for Futures fin bases that I made out of silicone because I occasionally make a counterfeit fin.
It’s sort of a lot of time to spend making a fin, but sometimes I have more time than $$ - Poor me… Or lucky me ?
But a good Futures twin set is over $70 last time I checked and I have to cut them down and foil them to make em the right size anyhow.
Fins like that hold up well and if you don’t over glass them they flex pretty nicely and they’re foiled with minimal sanding.
I forgot to mention - Prep the plastic by sanding with coarse sandpaper - New sandpaper
Have you asked your local surf shop if they have a “scraps/spares box”? Around here, a local surf shop in Morro Bay has a box of various singles behind the counter. You probably won’t find your exact fin, but you might something close.