Dear Dr.Fin! I ve been making fins for the last week.I made some with all kink of molds,I made some with colors,with or without cloth and I always have the same problem ...when the fin is ready I cleaned it with warm water ,before sanding and the fins are always too flexible with the heat!!!I m using epoxy west system...I surf in Maine so hot water never a big problem ...but I hope the board I made with the same epoxy will not get soft when expose to the sun???? (can it be the lubricant I use in my mold that mix with the epoxy)(I consider putting some cialis in the next try!?) thanks for your advices so far and excuse my poor english!
Here s some works I did The woods are bamboo from cutting board bought at the dollar store and works fine!
first..those fins are cool.. i was looking at those thicker cutting boards for handplanes..myself..
anyway.. i asked this question before but didn't receive an answer..
how solid are the molds for this...do you get any flex..deviations from fin to fin?
i worked as a rep to hospital cast rooms...and
used to hear the war stories of people breaking them all the time..
but never with fiberglass ones..
thanx,
dano
quote=canadiansurfer
I always have the same problem ...when the fin is ready I cleaned it with warm water ,before sanding and the fins are always too flexible with the heat!!...
End quote.
So youre saying that when you wash the fin in warm water the whole fin goes soft ??
How long are you letting it set for ? Leave it for a day or two Id offer. I use poly for fins.
I dont think the separating medium ( washing up liquid) would mix into the whole of the fin resin, but you could lay down a single layer of cloth first and wait for that to almost set before continuing.
did you glass the bamboo ones or just gloss coat ?
I would never have guessed that there was anyone else making fins with plaster casts.
BTW, is anyone molding Futures Fins ?
I know there boxes are copyrighted designs but I dont know if their fin bases are. website doesnt say they are...
Canadiansurfer: How are you doing the fcs tabs on the bamboo fins? They look sweet. Would it work to use wood as a core inside the fin when moulding? Im thinking it could reduce weight and add flex?
Danson: The plaster of paris doesn flex at all so your getting the same mould shape every time but it is quite brittle. I just make sure I make them thick enough and add some layers of plaster bandage cloth. Seems to work well.
I've also had some issues with the surface of the fin staying soft, but seems to harden up after a few days. It could be the washing up liquid or the cold weather that Im working in. I think I'll get some epoxy and wait till spring before I do any more glassing. Figured I will improvise by parking my car in the sun with the heaters on and use it as a hot box...
I think adding more layers of cloth should stiffen up the fin. Ive only been doing about ten but will trial and error it. I prefer the idea of moulding fins than sanding a foil from a fibre glass sheet and breathing in the shite. I think future fins would be a bit trickier as the ones I have, the side fins are at a slight angle to the base. Wouldnt worry about the copyright unless your selling them.
nickf- thanx for the info..i've been thinking about doing some fins..thanx for laying
the groundwork..
and i wonder about the copyright for fins also..seems like everyone true ames, rainbow fin co, x-rated , etc
make everyone's(fcs,future's, etc) fins..maybe probox larry knows the answer?
paging probox larry..please come to the white courtesy phone...
Ok! thanks for all the comments and..Dont be surprise that other people do fins this way.....I making fins with plaster mold because you taugh me how to do it Surffoils!and I will try to do a test with a layer of cloth as you wrote .I did my fcs tab with my jigsaw and sander, I only glass it ...no cloth.I did one with cedar and it bent when it dried.And I put a fin I made one week ago ....while in hot water it bent (very soft) its the red one on the pic...I dont really care for fins .....but it scares me about the board I made . Maybe west epoxy is not good when it is half an inch thick!!!
I thought about ' the softening " issue a bit...
are you putting just a thin layer of seperator down or a thick coat ? try a thin coat or try a few thin coats, with the car wax it does soak in to the plaster mold so it then makes the mold impervious to the resin. Try solid car polish in a can like in the earlier pics if youve got some.
The red fin looks like it has something mixed in with it, its got a kind of swirly whitish look on the surface ?
Are you just pouring the resin in and laying the glass or swirling the resin in the mold ?... are the ratios right?
1/2 in of Epoxy should be solid as a rock. Its a mystery why the fins would be soft ??
I just lay 2 or 3 layers of dry glass into the mold to begin, pour about 2 teaspoons of resin in and keep laying glass until it doesnt wet out. Add a little more resin, then glass. Gently.
I'll go home and do a carbon and veneer one tonight for Show and Tell,
they come out looking like the FCS Machado fins.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/ROBMACHADOSIGFIN_THR1.jpg[/IMG]
Great info Surffoils! Ive shied away from fin constructing just because of the sanding. I am interested in doing a silicone mold as I figure it would be even closer tolerance and less sanding. What is a starting point on the silicone/cornstarch ratio? What type of silicone- GE outdoor window silicone?
The recipe for my epoxy west system is 3 resin and 1 hardener.
Hi Nick, someone showed me the recipe for silcone / cornstarch in about 1975 , its common knowledge with computer nerds and garden variety geeks like me.
Go to www.instructables.com and search for SUGRU and OOGOO, theyve got more variations there.
I like the stuff, its a common thing to fix and build things with and can be cut, sanded and coloured, you'll think of more things to do with it once you try it.
hi surffoils
i really like to see your molding technique with the silicone-plain mixture…
maybe some pics and some details?
thanks a lot
klaus
I havent got any materials for that as Im doing plaster molds at the moment, but its dead simple, just read the posts on www.Instructables.com, they pretty much cover the basics.
If you havent tried molding before its probably better to start with Plaster of Paris to get a feel for it because the silicone needs to be handled quickly and with a bit of accuracy.
So here another easy way to make fins, these ones come out like the aforementioned Machado fins.
You can do it this way or lay it up in a mold for the same effect.
Get a piece of foam, just a sliver will do.This one is about 2mm thick.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias1.jpg[/IMG]
Outline and foil it but dont get too complex.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias2.jpg[/IMG]
Then cut out a dozen outlines in glass, 4 or 6 oz, and do 1 copy in 1/32 inch veneer.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias4.jpg[/IMG]
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias5.jpg[/IMG]
Cut about a 4mm strip off the outside of the foam wafer and chamfer (thin) the edges again. .
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias6.jpg[/IMG]
And position to see that its even all around.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias7.jpg[/IMG]
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias8.jpg[/IMG]
Now lay down 5 or 6 layers of glass ,wet them out.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias9.jpg[/IMG]
Put the veneer on top and then a thin coat of resin.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias91.jpg[/IMG]
Put the foam sliver on top.
And this is where you would put a piece of carbon on. ( But I dont have any at the moment) But first you would wet the carbon, let it set and then cut it out to a fancy shape.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias92.jpg[/IMG]
Now cover the foam and the carbon cutout with another 5 layers of glass. Youre aiming at making it 7 mm thick so you can add more layers of glass.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/sias94.jpg[/IMG]
When it all sets it, it takes about 5 mins to grind back the edges and a few swipes with the power sander and its done. I'll do that tomorrow.
In the end you would see the veneer at the back, the foam core in the middle and the carbon cutout at the front. Looks fancy but so easy to make.
and you can do the same technique in a mold and put in lots of cutouts so its different on both sides..
Heres a fin I made with this technique yesterday, just foam and glass, 5 in high.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/P2140107.jpg[/IMG]
And then after the sand I just put a thin coat over the top and polish. I screwed up with the tiny bubbles in the top left.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/6MAY012.jpg[/IMG]
So Ive got two ideas for side fins and I need a system with a full base so FCS are out, but Futures are perfect for these ideas.
I checked the Futures site and I cant find anywhere that says their fins are patented just the boxes.
So here goes.
Sliced a 7mm wide X 113 mm long slot in a block of XPS with a Stanley knife.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF1.jpg[/IMG]
Run some resin thru it, dry, light sand and then some car wax as a mold seperator.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF3.jpg[/IMG]
Make sure your final slot is the right size.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF2.jpg[/IMG]
And I prep the fin base by exposing more surface area.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF4.jpg[/IMG]
And glass it in place. I used chop strand mat.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF5.jpg[/IMG]
Check the cant.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF8.jpg[/IMG]
And left it to set with a hi-tech weight system.
[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/SURFFOILS%202011/MF6.jpg[/IMG]
I pulled it out yesterday but didnt get any pics.Tomorrow.
The single slot was easier to make than the 2 tabs of FCS.
I think Im liking the Futures system better for experimenting.
Reps are welcome to send me a box or 3.
how do you flick the fin out? i’m stuck at this step…
Hi Brett and thanks for the question, When you put( invest) the originals in contact with the wet plaster, they need several coatings of the carwax prior to coming in contact the wet plaster, so when the plaster sets it doesnt stick to the fin. Its good to think of plaster as the enemy, you need to keep your distance from it whether its wet or dry. Always use a seperator like carwax and several coats is better than just one.
So use the carwax on the originals before you push them into the wet plaster and later on,
do the same on the inside on the plaster mold before you pour the resin in to make the fin.
If youve got the originals stuck in the plaster thats now set, put the lot into a bowl of very hot water and any seperator will soften and even the plaster will expand enough to flick the fin out with a sharp knife edge.
I can make the fins for you if youre really stuck.
Yep, got a couple coats of car wax on the fin and plastic board before laying the plaster down. Just took a little scraping of plaster so the outline of the fin was free, and some tapping to free the fin enough to pull it out. Only pulled a little plaster away on one of the moulds. I’ll post some pics, came out really well. Hoping to lay up the fins in the mould next weekend. Thanks for the tutorial!