Hi, i am just starting to make my own fins and am having trouble finding good info on how to lay up a decent slab, any suggestions on how to make a mould or another way to do it. &
Does anyone have any ideas on what alternate materials i can use, I have made some wood fins and glassed them but any other ideas would be great.thanks
First link - laying up a fin w/ fiberglass:
http://www.swaylocks.com/forum/gforum.cgi?post=151400;search_string=fin%20layup;#151400
Second link - Bert Burger’s excellent tutorial on wooden fin building.
Make good use of the search function and the archives. Those were only 2 examples. There’s loads more info in the archives…
Good luck…
I would add some more tips, from someone who has been learning in the last year.
Use a different center layer in a symmetric foil fin. I’ve been using carbon fiber there, but a different color glass would work, or a piece of fabric. This become quite useful when you go to foil.
To foil, use a rotary sander with a soft pad and at the lowest a 50 grit disk. Draw a line on the fin with a sharpie to indicate the max camber line. Don’t do the extreme front edge - it is very easy to screw up with the sander, and very easy to do by hand. Keep the sander within 10 degrees of flat to the surface. Always wear a dust mask and gloves and long sleeves.
As you sand the fin, you will expose layers of glass. These are like topo-lines - they allow you to be reasonably precise in the foiling.
Once done sanding, work the fin over with 200 grit until smooth, clean the surface, and clearcoat it with lacquer. Then go surf it and enjoy riding on a fin you made yourself.
Also, I find 32 layers of 6 ounce works pretty well for a single fin finbox, it would work out to 22-23 layers for a thruster fin. If you are too thin, it is very easy to add scraps to the fin tab later. If you are too thick, you can sand or machine it down.
Good stuff by the Blakestah. Let me add a few things that might make life easier.
I make fins one by one, using three layers of 1.5 ounce mat in the center, plus a layer of 1/8" thick three-ply mahogany plywood on the outside. There are several advantages to this method.
One, the wood is 2/3 of the fin, and it’s lighter.
Two, the glass is at the center and forms the leading edge, just where you need rock resistance.
Three, the glass is at the trailing edge, where the fin is thinnest, and needs some strength.
Less hazardous dust;
Wood is easier and quicker to grind.
The wood layers are a good guide to how evenly you’re foiling.
Final smoothing is easier on the wood.
It’s cheap on materials.
I use a 50-grit disc on my grinder initially, then (sometimes) 60 grit by hand using a hard block, then the soft pad might come out for smoothing if not the 100 grit quickie hand smoothing.
Be sure you adequately wet the wood when you’re glassing these on; I use a 1" brush to glass on a fin and it comes out pretty well; rope and two layers of 6-ounce on each side.
Question,
When foiling do you place the fin in a vise so its in a vertical poition or do you clamp it down to a table w/ c-clamps?
Aloha,
Joe
Hi Joe,
I hold the fin in a heavy duty work glove and go at it with my orbital sander. I’m sure there are better methods. Don’t forget the glove. Ouch! Mike
“…Does anyone have any ideas on what alternate materials i can use, I have made some wood fins and glassed them but any other ideas would be great…”
I like using thin foam core [polyurethane] from time to time . And now we have PlusOneShaper’s secrets revealing “moulding fin base” / ‘fin base moulding’ threads, I no longer have to worry / puzzle about how to make the bases strong . Hallelujah ! …heck , the ‘Hickster’ even made one out of CARDBOARD core [!!] … ben
Question,When foiling do you place the fin in a vise so its in a vertical poition or do you clamp it down to a table w/ c-clamps?
I use a bench vise and hold it vertically. I’ve been meaning to mount a vise to the wall so I could hold it flat with the ground, I think that would be optimal. C-clamping it to the bench works OK.
An old shaper (started in 58) that still makes fins for every board (says they are too important to not customize for each board), does it in his two hands. Left hand holds the 4 inch sander (24 grit paper), right hand holds the fin. His fins are smooth, although he is not as concerned as I am with foils. He doesn’t mark a max camber line, thin the tip, etc.
BTW, since I discovered the power of a good roller in a layer, I use 1 layer of 1 ounce for every 0.01 inch thickness, or 35-37 layers for a single fin, and 25-27 layers for thruster fins. Every layer rolled heavily for maximal glass to resin ratio.
hth, happy fin making.
I think clamping the fin is backwards. I clamp my belt sander to the bench, use the little red button on the side to keep it on, and hold the fin down to it.
The round end of the belt sander gets into the trailing edge just as well as you like, the flat section takes off material in a hurry, and you never have to unclamp your fin to look it over.
Plus, I’ll never hurt myself with the sander if its not moving, its got an outlet for the vac so I’m pretty dust-free, and it clamps down easy with 2 little bar clamps on the front & back handles…
check out post: “awesomest material for fins” I think you will like it