OK. So I checked in the archives and found the answers to almost every question but the one I really need to know.
I have a set of wood keels that I shaped from an old longboard skate deck. The inside has a nice concave and I am anxious to get them on the board and get this thing done.
My question is: Do I have to glass the fins before I glass them on the board or can I do it all in one step? Glass the fins while I glass them on the board and then do the fillet with fin rope and two more layers of glass after the first layers set? I have already coated them with epoxy as suggested in the archives.
Reason I ask is that its not possible to glass the unfoiled side on a flat surface becasue the unfoiled inside of the fin is curved not flat. If it were flat it would be a no brainer.
I am thinking in my head that I can but I just know there is some unknown pitfall I am not seeing.
Thanks,
T
P.S. 8 layers of rock maple sure does look pretty all foiled out but it is HARD! Used I dont know how many peices of 40 grit paper to foil them.
Here's what I would do... Mask the flat side to the edge. Place the fins flat side down on an upside down paper cup. Drape a few layers of cloth so it hangs over the edge all the way around. Pour some mixed epoxy and spread it around with your fingers. Ideally you will have a saturated cloth apron hanging all the way around each fin. After it cures to a 'green' state (not fully hard) cut the excess apron with a razor blade so you have 1/4"-1/2" left hanging. Flip the fins over and remove the tape. Take some fin rope or individual strands of fiberglass (just shred some scrap cloth) and pack it inside the apron around the edges. Drape a few layers of cloth and epoxy those to the flat side. Make sure the individual strands around the edges get saturated. Once fully cured, use Dremel/file/surform/sandpaper and clean the edges. Stick 'em on your board. I'd use at least 4 layers and some fin rope per side. All the layers don't have to go all the way up the fins.
Wooden fins tend to be kind of fragile so it is a good idea to glass them with edge reinforcement before putting them on the board. With any luck your finished fins will have a glass bead around the edges.
I don't glass them before I glass 'em on. As long as you paintd a thin coat of resin over them to prevent the wood from sucking resin or blowing your lam. kick a SMALL amount of resin on the bottom of the fin to set the correct cant. Once kicked, wet out fin roving, and three layers of cloth on each side, all at once, don't let the roving kick first. make sure that there are no bubbles. the only reason I can think of to glass them before they go on the board is if you want a nice little glass bead around the leading and trailing edge of the fin.
Next time try grinding them with a hard backing pad and 36 grit to save some $$$ on sandpaper.
I'm not sure what you're trying to say about it being impossible to glass because of the curved surface. If I understood you correctly, you could glass the convex side first, flip it over and do the concave side. If both were convex, say a 80/20 foil, I'd leave excess wood on the base of the fin, foil, and then use that excess wood to clamp onto a table so that the fin wouldn't wiggle around as I glass it. Then once glassed, I'd cut the bottom off.
They can definitely be glassed. What I was trying to say was that both sides couldnt be glassed at the same time like a flat sided fin(these fins are cut from a skate deck and dont have a flat side). I didnt want to have to glass one side at a time because when using epoxy it takes a while to gel. I am going to go with KK next time I do a board but I am triying to finish up the resin I have now which takes a while to gel. My board building time is precios so I like to try to do everything as effisciently as possible so I get the most done possibly in each session.
So if I understand you correctly you lam three layers of cloth on each side of your basted but unlaminated fin while you install it on the board? If so this is exactly what I want to do. I just dont want to run into any unforseen pitfalls while doing it.
No, If you are not gonna lam it before you glass it on then you need to have cloth covering the whole fin.
when glassing on the fins, after you kick a small amount of resin underneath the fin to achieve desired cant and tow in angle, take a little fin rope and wet it out. Placethe rope on the fin base, and squeeze out excess resin, and bubbles, next take cloththat goes up maybe 2" of the fin depth, and covers 2" of the board bottom , and lam it on. Then take cloth going 3" up fin, and 3" onto the bottom of the board and do the same, then cover the whole fin with 1 or 2 cloth layers that would go about 4" onto the boards bottom. all cloth layers should run the length of the fin base, and excess overlap cloth can be grinded down when hard or razored when gelled. If you razor when gelled leave some sanding room to sand off the ugly cut line.
I hope you get what I am talking about. I make sense to myself, but maybe not to others :)
Again, I don't know how important a glass bead is to you, but this method may give you a small one.
P.S. do all of the fin rope, and cloth layers at the same time meaning, do not let them gel or kick. you should have time, and a paint brush with the bristles cut short helps when lamming around tricky corners.
No, If you are not gonna lam it before you glass it on then you need to have cloth covering the whole fin.
when glassing on the fins, after you kick a small amount of resin underneath the fin to achieve desired cant and tow in angle, take a little fin rope and wet it out. Placethe rope on the fin base, and squeeze out excess resin, and bubbles, next take cloththat goes up maybe 2" of the fin depth, and covers 2" of the board bottom , and lam it on. Then take cloth going 3" up fin, and 3" onto the bottom of the board and do the same, then cover the whole fin with 1 or 2 cloth layers that would go about 4" onto the boards bottom. all cloth layers should run the length of the fin base, and excess overlap cloth can be grinded down when hard or razored when gelled. If you razor when gelled leave some sanding room to sand off the ugly cut line.
I hope you get what I am talking about. I make sense to myself, but maybe not to others :)
Again, I don't know how important a glass bead is to you, but this method may give you a small one.
P.S. do all of the fin rope, and cloth layers at the same time meaning, do not let them gel or kick. you should have time, and a paint brush with the bristles cut short helps when lamming around tricky corners.
On raw wood fins, you should have some bead of glass along the edges. You’ll see what I mean after you install them and have to sand the foil back in. I only use poly resin on fins (even if it’s going on an epoxy board). There are several ways to put a bead on, but you have to do it with the fin off and horizontal. You can cast one in solid resin with some creative taping, or put the fin on wax paper over a flat surface and do it with a clear thick filler. Or do it like John recommends with rope.
Once you have the bead on and sanded into shape, set and align the fins on the board using a hot glue gun; don’t let the glue ooze out past the fin base. I don’t use rope, but make the fillets using filler, and sand to shape before laminating the fins in place. There is no strength in fillets anyhow, it’s all from the cloth on the sides. Use two pieces of 4 oz cloth per side of each fin, completely covering the fin (about 1/2" margin at top), and going outwards on the bottom at least 2". Hotcoat and sand eveything to shape including whatever refoiling needed. Keep in mind that this is all done with poly resin, so be sure where the fins will be glassed on is very rough 60-80 if the board is epoxy. I’ve done many wood keels on epoxy boards this way and never had any come back.
You can do glass-ons with epoxy, but you’ll need to pre-glass the fins first. Epoxy will be very difficult to work with on vertical surfaces also.
Could you elaborate on why it would be harder to glass with epoxy rather than poly in a vertical orientation. Does it have something to do with the resin draining?
I basted the fins in an upright position to test whether they would drain and they did fine. I guess the cloth could change all that though.
I'd go with PeteC's advice. However, you can glass fins on with epoxy. I build up the bead with at least one layer of glass on the fin pre-glass on. It doesn't matter if you use poly or epoxy for this step, epoxy will stick to either one. I think Pete might be using poly to glass on the fins because of the cosmetic issue of the epoxy clouding up in the fin rope at the base and sometimes in the multiple layers of cloth glassing the fins on. You can minimize this by not overworking the resin while getting the rope to absorb it and don't over squeegee the layups.
If you do glass them on with epoxy make sure everything is laid out so you can move quickly. Keep stirring the pot or have ice bags to keep it cool. Epoxy can get really hot when it sits in a pool. It will melt plastic containers. Mike
I use poly because of heating and air bubble issues using rope or filler-fillets, and it is just faster than epoxy. And, I prefer the clarity of poly on the fillets and beads. Use a brush to wet the fin before applying the cloth. On the filler, I use cabosil only with resin. Some types of cabosil are very clear, and others get cloudy, so test it first. If I’m really rushed, I will use UV catalyst + small amount of regular cat. Using 1-5 min epoxy like Brain shows in his video is also good, but nothing is as fast hot glue. You only need to get the alignment to hold during the rest of the glassing process. Be sure to mask off the bottom, once you get the fins in it will be very hard to get the sander in there to clean up any mess.