Bill...you're silly, everybody knows seals can't glass..or at least glass on fins.... I did see one try a resin swirl once. but I digress....They have no apposible thumbs.
Resinhead,
Don't call me Silly, and don't call me Roy either!
Align the cloth so that ALL glass fibers are at 45 degrees to the base of the fin. I'd use a minimum of 3 layers on each side, more for permanent attachment.
I went back and re-read this…
http://www.thereefjournal.com/files/7._Lavery_Foster_and_Carswell.pdf
There’s a lot of good info there about lift and drag.
I believe you and I do our glass ons the same way, except for the roving, which I advocate. I could be wrong here, but it has woked well for me. The article is interesting, and admittedly inconclusive. But for single fins (and trailers), it seems that the evidence points to the use of roving having advantages.
I read the material. It's not the first time that results from modeling, and tank environments, have been at odds with real world experiences. If you would like to discuss the matter, PM me, and I will provide my phone number to you. I'll be glad to explain the emperical study that led to my conclusions. The referenced study was conducted in 1959 by my friend Mike McDonough (an engineering student) and me. His balsa surfboard was the test vehicle.
Where do you think I need more glass, on the inside or the outside of the fin?
My intuition tells me that most of the force on the fin will be on the inside base.
Also, as far as a fillet, it would seem that it would be better to have it on the inside of the fin. I don’t see any reason to put it on the outside of the fin. From a strength, or water flow prespective.
maybe pointing out the obvious for you but just in case want to say that there’s no need to tack down all four fins at the same time; do the fronts first then trailers.
tight spaces, resin setting up, lots of things to catch your hands on.
2 cents from a backyarder
Strange....., I have the same white shoes as the Spaceeman.
Are those paint sticks holding up those fins?
Remember when Gabriel Wisdom, and JM in the PM from 101.5 KGB had the OB Spaceman sometimes do the daily 12 o'clock report.
Classic
Maroudis grew me my TV! Never thought it would work.
Yep, those are paint sticks holding up the fins. It worked perfect. Fins are 1.25" from the rail, and fronts are 9 degrees, and backs are 7 degrees. All of the fin tips are parallel with the rail, just like GG’s boards. The fins are pretty far back too. 10.5" for the fronts and 5.25" for the backs. Similar to GG.
My only concern now is that I don’t have enough glass holding the fins on the board. I have a small, insignificant, amount of roving on the inside of the fins, 3 progressively smaller layers of 4 oz. s-cloth on the inside, and 2 layers (one full size of fin, and one half the size of the fin) on the outside.
I am considering adding one more layer on each side of each fin.
So, after the first glasson setup, 3 staggered layers on the inside, and 2 on the outside (all 4 oz. S), the fin wasn’t stiff enough to the board, when I would press on the fin, it would flex at the base, increasing the cant. Which is something that I don’t really want, I want the fin tips to flex not the entire fin to change cant.
So I added a bunch more fin roving to both sides, and 2 more layers (one 6oz. and one 4oz.) to each side of the fin, that go 2" up the fin, and 2" on the board. But the fins still bend at the base.
I have to be doing something wrong here. Why are the fins bending at the base, increasing cant?
OB
did you do a fin patch on the bottom of the board?
Ken,
The board was glassed with 4oz S-cloth on the bottom with a 4oz S butterfly patch on the tail, so there are 8oz. under the fins.
…man, your something like a pig headed…
read what I put in the previous comment about those epoxies
that is one of your fin problems…
-sometimes this problem occurs when use UV resin with fillets.
by the way, I don t see any advantage in time and consistency in your method
but may be I can t see the whole concept…
ok … if you really want to know. glue guns and superglue are cool enough but not as strong as when you set in roving and resin. some one told me a HELL awsome trick to do glassons .no tape or glues . fast and accurate. if anyone wants to know give me a PM
How I did these glass-ons without roving (heh, heh, heh):
there are certain advantages to building your surfboard out of plywood!
...OK, gotta go send my pm for the inside skinny!
I don’t quite get what you are trying to say, but I don’t think the method used to initially attach the fin at its toe and cant, has any effect on how the fin deflects from sideward pressure.
What method are you speaking of? Glass and roving? or are you talking about setting the fin tips parallel to the planeshape?
...
Pay $12 and buy a book called "The Ding Repair Scriptures" by George Colendich.
Read the book and then it will all make sense.......
Never did and epoxy glass on job, why...because they are too ugly to do. You never get a clear lam. Plus boxes are way faster and in my opinion stronger when done right.
But a poly job. Lay down your glass patch...you need the patch cause when you start sanding the whole mess you'll be glas you had the extra buffer. Tack fins on patch, lay roving around fins, put glass over roving, lay roving down again, put glass over...sand whole thing smooth, gloss. It wont move, when cured.
Maybe you are working too fast with epoxy, maybe it's not cured enough to be bending it and F'ing with it.