Been lurking and reading with interest for a while - some very informative stuff on here!
Anyway - Having been mainly experimenting whilst repairing old boards and friends dings I have a new project. Have read through a fair few posts and searched the forum but havn't quite found what Im after - most wooden fins posts seem to be for glass on fins.
Ive glassed a few ply fins on old boards just to mess around on but...
Id like to knock up some ply fins with FCS tabs - mainly so I can try out some wierd shapes and swap them out easily.
Essentially my plan was to
1. Shape some ply (poss use nicer wood later if I get the hang of things)
3. Couple of layers of 4/6oz? with roving - lam/res mix.
4. Hotcoat.
5. Errm.. (This is where my tab issues are!)
6. Polish... go surfing.
My main issue is whether to leave the fin tabs as part of the fin and just seal them when I hot coat - or whether to make a mould and use a chop strand/res mix to add the tabs after. I dont mind a bit of filing to get them the exact size and this allows me to angle the fins if I want.
Im currently using poly resin although I can get hold of epoxy easily.
Thinking and reading about the same thing for a few days, I’d do it like this (although no experience with tabbed plywood fins, only glass ons up to now)
foiling the fins, with tabs, but thin tabs that leave enough room for additional glass
Glassing the fins, putting some extra glass at the tabs, but still below 6mm thickness (thats the fcs tab thickness, isn’t it?)
Creating a mould (actually two) by sticking a FCS fin in silicone or something else
Putting some chopped glass and resin in the two moulds, stick the fin in and let it cure
remove fin, clear transition between tabs and fins
[this is from the 'agave fins' thread ].... I did it with a very thin sliver of agave ....and LOTS of layers of glass in the tabs [very little wood at all in the tabs ]. Fiddly.
But , if you can make moulds , it may be worth experimenting with . [At least wood is cheap !]
good luck , 'Slicks' .... and please, post up some pics of your results , eh ?! [ I always like to see how others approach things ...it gives me new ideas to try !]
this might be the info from that page I 'linked' you to , that hopefully 'might' be of use ...
re: ' fin panel inlay ' agave fins ..... Posted: September 24, 2011 - 10:12pm | #25 (permalink) |
okay ... so I coated the inside edge of the agave 'sliver' , with lam resin .
Then placed on two layers of 6oz cloth . Wetted it out thoroughly , then placed it carefully onto the glass pane , which was coated in lam inating resin also . Placed on three more layers of 6oz , brushed resin over as each layer was added .
[I wanted to make sure it had a fair amount of fibreglass covering / strength to it , BEFORE applying the roller for the remaining layers . ]
Again , as with the green tinted panel , I laminated four layers at a time , slowly and carefully , with the roller ....air bubbles around the edges of the fin being my main concern [to avoid] !
I've tried different methods for tabbed FCS fins and the best I've come up with strength-wise, is a G-10 base with the wood glued to it with epoxy then glassed over down to the base. Not the prettiest, but they don't look too bad either. I guess one could paint the G-10 prior to glassing, or add a veneer over it for aesthetics. Me, I just like the idea of fins that have some semblance of buoyancy to them.
Thanks Ben - that thread was just the kind of thing I was looking for.
I did wonder what agave was to be honest, but there is a distinct lack of all things Palmtree-ish over here in sunny England! I'll stick to my cheapo plywood for the moment, then have a look for some bit of pine/oak or similar with a nice grain.
Making moulds shouldnt be too much of an issue - Im waiting on some cheap sheet glass & resin to turn up that Im only using for mould making and I will have a few attempts at tabs.
Im hoping my order of things to do is about right - Im planning on adding the roving after a couple of layers of glass.
Not quite sure how well the fins will bond with the tabs if they are added 'after' - but I guess if they break off mid session at least they wont owe me bundles of money!
edit:
Surfthis - just to confirm you are using an existing fin and adding the wood and glassing over?
I know fcs fins are pretty cheap but seems a bit expensive - or have I misunderstood the process?!
Surfthis - just to confirm you are using an existing fin and adding the wood and glassing over?
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Nah, that's a panel of G-10 that's 1/4" thick. Super strong but pretty easy to foil. You could use just about any type of fiberglass built up to thickness, or close to thickness, with the same or similar results.
Thanks Chris. The front fins are just G-10. The rears are a take off on a set of inside curved fins glassed on an old fish that I made from a broken skate deck several years back. Instead of glass ons, I cut out the base for G-10, clamped and epoxied a sacrificial piece of G-10 to foil the outside part of the curve. Set the cut out skate deck where the curve looked right and epoxied them in place. When it set I ground in the inside and outside curve, foiled the fins, then glassed over everything but the tabs. Sanded all that out and there it is. I'll say this, maple is a bitch to foil!
Here's some I made essentially the same way, but I made a form to bend thin baltic birch ply into curves. Glassed the insides with a layer of carbon fiber. For some reason, I don't like the feel of these too much, so I don't ever use them. BTW, that's not the board I made them for. Just put 'em in there to check the fit.
You can also lay up a fiberglass spine with about 10 layers of cloth. Add your wood but leave enough of the spine extending below to seal the base of the wood and to build up your tabs.
Foil the wood, add fiberglass to the tab extensions then cap the wood and the tabs with 5 or 6 layers of fiberglass. This will give you a halo of glass around the wood edges for water tight protection. I use a Dremel cutoff wheel and 2" grinding disc to trim/grind the tabs to fit.
For center fins add wood to both sides of the fiberglass spine. Use wood 1/2 the thickness of the wood used for side fins.
The same basic method can be used for other box/plug types.
I've seen so many of the solid wood fins that were only wrapped with fiberglass have problems. The lightest tap - they crack and start leaking.
Here is a pic of a fin with spine/halo extending down through the tabs:
im currently building my own. the way im doing it is with a 8mm birch ply with 7 plys, 2 x 6oz glass and epoxy. my tabs are left as part of the fin. the way i thinned them out was by removing 2 plys either side of the tab,dropping it to arund 3.5mm thickess and then glassing it with the fin itsel. thisway the tabs are part of the fin, and the glass supports the entire structure.my second layer is cureing at the moment and i will post photos asap. fcs tabs are 6mm thick,and i will/might have to do some sanding or maybe even adding of glass to achieve my 6mm. after everything is done,shape the tabs correctly and wala!
thanks for your feedback guys [nice to see some / a tiny handful of the [I am sure , MANY !] finmakers here come out of the closet , at least once in a while ! ]
'Slicks' , don't feel bad , mate ...
I didn't know what 'agave' was either , until Ross the boss did his famous 'tequila madness' thread [warning : 13 pages of it !].... it all made sense then ?! [well, kinda ....]
hey im tyring to follow how to make a set of these awesome fcs fins. If i understand correctly. you lay down a ton of strips of cloth to build up the proper depth of the fcs tab. Saturate the strips with resin, then place the rough outline of the wooden fin’s base on top / perpendicular to the glass strips. THen you foil the fin after it dries, and lay your cloth along the sides of the fin extending down to the fiberglass tabs to bring it all together.
I want to make a pair of larry gephart syle quad fcs fins. Going to try and find a sheet of baltic birch marine ply. Do you know how many plys and how thick geppy uses?
