I want to make some superlight glass-on fins using foam as a core.
I have some texalium to beef up the stiffness if needed but was really looking at just vacuuming some pre-printed asian yoshi paper on the foam before glassing them up for some added effect. How many layers do I need on each side 6? or is 3 layers of S and some roving around the front edges enough?
I’ve never seen any one post foam fins here yet mostly wood so is there something I need to be worried about.
I already cut out some keels out of 1" 1lb and a quad set out of 1/2" corecel to fair up…
I’m also interested in doing the same thing. It seems like it would be a lot more fun to shape than the wood, it would be easier to tie it into the molded base, and I would like to bring some color to the board.
Yes ive made foam core fins,usually using higher density foams such as d cell etc and using the same system that i did a post on some time back
I think the post name is as below
vac forming fins and adjustable fin boxs for home builders
I make them to suit FCS plugs by just making two small tabs there is no need to use carbon ordinary uni directionals
Ive made them with as little as two layers of 4 oz glass, there strong but do not take impacts that well
So as long as you can surf and not hit any thing they work well, the bigest problem I find is transporting I allways manage to wack them on the car door or house walls etc
Ive never tried Eps Cores,you would have to be carefull that you maintained the correct shape with such a soft foam
Corecel to me is as light and tough if not tougher than balsa so it should work.
I was a little dissapointed with the dcell/wood fins I got from Fiberglass Hawaii the other day as they seemed way to flexible and I really like stiff fins… maybe some nomex might be the answer cause they have glass-on’s with those cores as well just not in the shape I need for my fishes…
Great thread though got to remember to save that one off along with Bert’s fin thread.
Hey One - Don’t know if it helps, but I made hollow fins before w/@ 12 layers of 6oz. Worked great, tough, etc. I did it on a whim, as I was laying up cloth to make “fins,” and when I realized how thin 12 layers was… I figured I don’t wanna spend so much time and money to lay up all this, and the first sheet seemed pretty strong, so…
My feeling is 3-4 layers 6oz/4-5 layers 4oz - if you’re glassing on esp. - should be great.
Looking forward to pics of all your projects, not that I ever posted a pic, but I do love 'em.
if making stiffies via lots of shell fabric (fg or cf) then any foam will do.
I made foam core, carbon/fg shell fins using 2 part pu foam using a fg fin mold i easily made myself…lots of vaccy pulls…
thick foiled, superlight, superstiff, super floaty…
butt ugly cosmetics tho…paint might make them look better
i preferred molding cuz i didnt think i could make symmetric hand shaped foils…proly could with some practice tho but i dont have much time or patience for fin foiling…i guess i prefer to buy fins and focus on boards
So 3-4 layers of 6oz or 4oz S on each side should be enough
maybe a layer of tex and then the colorful chinese patterned rice paper and 2-3 layers of regular glass over that should be plenty stiff with the aluminized tex… Just hate to waste the Tex since I’m doing the rice paper stuff. I saw some silver tex fins someone else did a while back and they looked nice but shark/barrcuda bait for sure…
I don’t know about molding its too much work, I’d rather just sit down and foil since it should cut like butter(with the exception of the corecel) with a block and some 36 grit… I did these back in one of these thick fat fully foiled foam guys back in '72 pattern after Hyson’s experiment but I don’t remeber that far back as to how it worked… A little bit cloudy back then…
Sab’s stuff is definitely unique
I believe Berts teased us with a black carbon one of his back then too…
Yeah Meecrafty you said it…
I think my mantra may one day return to… “i’d rather just buy my surf equipment and concentrate on surfing!”
When I make them again , though , I will use VERY thin foam core , and lots of layers of 5 or 6oz cloth , to make the fcs tabs solid glass, instead of foam cored.
They felt GREAT while they lasted , as did Wildy’s q-cell type core and epoxy glassed fins he sent me …light , responsive [almost ‘alive’ feeling , somehow !]
Here are a couple of foam core center fins attached. The glass on was done back around '73, I still have the board. The flowered one is on my 9’10" Hap Jacobs. For my money if you want a rigid glass-on fin that’s super light a foam core fin is hard to beat. I put a spine in center fin singles. For center box fins I draw the line at 8.0". Anything smaller than that you just loose to much strength for the weight differental. With new carbon, kelvar, fiberglass & epoxy composite construction available it only makes sense to make high performance fins out something that more resilient, lively and durable. However for glass-on grand things are possible with foam core fins. For rail fins you don’t need a spine. For the center fin foiling raw foam would have to be done completely by hand. One could do the same thing with rail fins and then put a shell over the foilded foam. For rigid, thick longboard Bayne box fins it’s the way to go. The fin that comes up on this sight next to my posts is one I made for one of Al Baggetts Lance Carsons. It’s shown at the raw foam stage right after foiling and before any cosmentic work was done. He wanted a fin an inch thick. I missed to a couple thousands, oh well ~~
The first ever fin i made was made using corecell. Made for a fin fin box. Made the fin from two pieces of corecell foiled each side individually and then laminated together sandwhiching in the fin box piece that was made from wood. The fin was hand laminated with a 50/50 carbon glass mix with polyester with 4zo over the top of that.
A final hotcoat was applied and then sanded. See photos. The fin worked well until the wooded fin box part broke, the fin itself was more than strong/stiff enough.
Will definately be vag bagging the next one and reassesing my fin box insert construction.
I’m on the same program as you meecrafty- except that I find that making my plugs out of harder wood (such as poplar) is actually easier in the long run- here are pics of my newest set of plugs- fins for my fish. -Carl
As always, beautiful work, Carl! The vertical cord is well placed IMHO. ~ These look like they’ll be glass-ons, but I guess if you were to cut holes up into the bottom of the fins and insert hardwood plugs for the fin tabs they might work for FCS or Lokbox. It occures to me thatfixing the fin tabs on the fins before foiling might be the best approach.
its just a simple molding technique using a vac pump, plywood board and plastic sheet.
i copied/molded a fin a really like but molded it thicker by propping up the leading edge, pic3…pic 2 is the foil comparison of the original v. the modified copy…pic 1 shows the molded results…the foam is molded around the balsa, which is reinforced with fg
basically if you have a vac pump and plastic sheet you can figure out how to do it…the plastic just prevents things from stickin together when processing. i used suncure resin to make the fg mold…plywood board, plastic, fin, plastic, fg/resin then into a small vac bag and when its just right let the sun hit it and in 5 minutes you got the mold…to make the foam core just put the FG mold alone in a plastic bag, vac it and pour 2part pu foam into the cavity, flip it down on plastic covered ply, hold it there for 5 min and badabing, molded fin core.
Blue resin base fins are XPS, 4oz., Balsa, 4oz., 2 layers of 5oz.carbon in the middle with the FinThing attachment.
Dark and Light colored fin on right is 2 layers carbon, redwood/bamboo (no Foam).
I’ve tried the foam/balsa fins on three different occasions. They ‘ding’ easily and the last surf with them I broke three at the base. I think I need to put more layers of glass on or go back to wood.
The XPS/Balsa fins are 3/4" thick… I LIKE THE THICK ONES!!! They seem to turn easier with more drive!
Oh ya… so far no delams from the XPS and their sitting in the sun.
I’ve also been thinking about composite fins etc etc…
One idea i had was perhaps instead of foam, what about gel core structures? Or a softish plastic core structure…
I’m not talking liquid gel but say rubbery type material, greater flex and strain capabilities… maybe with a nice skin of carbon fibre to give some strength and rigidity…
its just a simple molding technique using a vac pump, plywood board and plastic sheet.
i copied/molded a fin a really like but molded it thicker by propping up the leading edge, pic3…pic 2 is the foil comparison of the original v. the modified copy…pic 1 shows the molded results…the foam is molded around the balsa, which is reinforced with fg
basically if you have a vac pump and plastic sheet you can figure out how to do it…the plastic just prevents things from stickin together when processing. i used suncure resin to make the fg mold…plywood board, plastic, fin, plastic, fg/resin then into a small vac bag and when its just right let the sun hit it and in 5 minutes you got the mold…to make the foam core just put the FG mold alone in a plastic bag, vac it and pour 2part pu foam into the cavity, flip it down on plastic covered ply, hold it there for 5 min and badabing, molded fin core.
HTH
Cheers
Thanks Meetcrafty. Now that I have a pump, I think one of these days I’ll try something like that.
