In the past I’ve seen photos of wooden/fiberglass laminated fins with crystal clear trailing edges you could read a book through. No visible shade from the cloth at all and apparantly plenty thick too. Surfer’s Journal had photos of Greg Noll’s boards a few years ago with this type of glassing. I’ve made wood/clear fins, but can always see shading from multiple cloth layers. Are they using a special resin? Casting resin? Epoxy? Thanks in advance for your help.
that Greg Noll article also had some sweet pic’s with the tail blocks. nice thick bead of glass at the tip. how?
There used to be a glass rope that they used for beads. Today everone uses continuous roving which is what they use in chopper guns. Roving has quite a bit of finish on it so it won’t gag in the guns. I haven’t seen that glass rope in years. Probably 20 at least.
Beleive it or not I ran across rope in furniture restoration catalog “Vandykes”.I think that Greg Noll did those fins in clear resin in some sort of a mold…this was via Jim Phillips who does some of Nolls work.Where is Jim anyway???
If you need to do clear castings try Silmar S-41 or S-40. Same base as S249A but different promotion package for clear castings. You can buy from either Crystaliner in Costa Mesa or Fib Hawaii. Reichhold also makes a quality clear casting resin. There is a lot of different sizings for rovings, unfortunately clarity isn’t something they are trying to achieve in making them. I would talk to David C. at Fiberglass Hawaii. If anyone knows what roving is clearest, David would. Sluggo
What about Lexan? Lexan is bullet proof. I have hit a 3/8 lexan sheet, from 5 feet with a .38 slug. it only made a dint in the lexan. Then you take a piece of Lexan and flex it (like a fin would flex) and it with crack. I drilled a piece of Lexan and taped a pipe thread in it and screwed down the fitting. Came back the next day and the Lexan was cracked in about 4 places. They are called stress cracks. Lexan is not a good chose for a fin.
As I recall, there were a series of posts about the use of acrylic sheets to form resin beads. Not sure what they would be listed under in the archives. While I have tried this method, I am not sure it is any easier than building up a bead of resin on the fin edge. The problem I found was in the finishing and shaping of the acrylic. Don’t use any high speed saws or grinders. They will cause heat build up which will cause smearing of the surface and make sanding gummy. The best tool I found for shaping was a cresent patterned auto body file. For sanding I used silicon carbide papers up to 600 wet. For polishing I used a sewn buffer pad and white compound. I believe, the white stuff is sometimes called white diamond. To finish I used Mirror Glaze. A method I tried but could not master was flame polishing. The idea is to pass the flame over the edge of the acrylic until it just starts to melt. If you try this practice on some scrape. I didn’t and ended up with a serrated, black fin bead and a lesson in how easy it is to blacken cedar. Hope this is of some interest and help. Take care and have fun. Patrick.
Patrick, I flame polished professionally for many years. But instead of an actual flame, try an industrial hot air gun. Find one that has variable temperature control, at least 350 to 950 degrees… never forget to keep it moving!
cleanlines, I look for the rope in Vandykes. Could not find it. Where is it?
Bagman I will have to dig up the catalog but as I recall it was in the section where they sell fiberglass,resin,casting resin and all that good stuff.The catalog is an earlier one so maybe it is gone.I will check it out.As for the resin bead thing here is what Jim Phillips told me as I best recall.You have to have a planer…a stationary one.Glue up fin panel…plane to 1/2 inch thick.Cut out fin…use a slot bit in a router and cut slot around fin in the center (this keys the resin.Wax a peice of glass and stick the fin to it…build a mold around the fin and pour casting resin (not too hot).When it gets hard run the fin blank thru the planer taking light passes on both sides until it is 1/4 of an inch… foil the fin and prime with lam resin.You are ready to glass it on.The final bead cleanup is done after the board is hotcoated.Easy eh??Or better yet have Jim Build it for you. R.B.
Great idea. I will try the hot air gun next time. Thanks Dale. Patrick
Casting seems a bad idea to me. I’m afraid it wont be very strong. A little structural integrity’s a good idea as far as I’m concerned. I can pretty much make the cloth lines disappear with the clear acrylic spray #117 made by AERVOE. It’s laquer base so it dries right now! I get it from Fiberglass Hawaii. After I get the shape I want I just sand to 220 to get things nice and smooth and spray several light coats on. Then I wet sand and polish. It turns out pretty nice. A can costs $3.25 and it’s time saver that works pretty well. Worth trying once anyway. It’s great way to kill the cloth lines in the lay-up and put a nice thin skin on you can bring up bright. Gone Surfin’, Rich