Matching fin for First Board

Used 40 layers of 6oz glass with cotton cloth in the middle, the same cloth I used for the nose of my board http://www.swaylocks.com/forum/gforum.cgi?post=256445;search_string=first%20board%20pics;#256445

I also experimented with boat resin (cut out on the right) and I think about 20 layers of cloth, about as many as I could make myself cut before I got tired of it. The boat resin turned out pretty ugly since it’s so yellow. No sparklies though I think. Maybe because of the resin, maybe because I wasn’t as tired when I did it because 20 layers is easier than 40.

This is a for a fins unlimited box. I know somewhere I had read exactly how many layers to use with what boxes but I was too lazy to look it up again. Turns out 20 layers is too few for the width and 40 layers is too many. I think I used 64oz of resin for the 40 layer fin. Not going too much bigger than the fin on the rectangle I laid up. I also wasted proabably 32oz of resin burning it by having it sit in the cup. After that I started using dixie cups to wet out 2-4 layers of cloth at a time.

Left something to clamp at the bottom while I foil as well.

Cut it with a band saw, tended to wander, probably needed a thinner blade. Cleaned up the shape with a dremmel when I went to foil.

Clamped into a vice and foiled using first the dremel to rough the edges then a palm sander to sand… and sand… and sand… till I got sick of it and said good enough. There is a rather wide flat area in the middle of my fin.

Dremmeled the slot tab, one side is nice and smooth, the other side has waves in it. I dremmel better on the right :stuck_out_tongue:

I tried doing both sides at once with a fairly thick coat by taping it to the edge of my outdoor table with blue painters tape. Came back to check it 2 hours later and it had fallen in the dirt :confused: Sanded it all off.

Next I taped off one side at a time and put a thick coat on which ended up with big flanges sticking off which I had to grind off and redo the foil somewhat which resulted in my sanding into the fiberglass.

Here it is with a thin wax coat put on both sides while clamped in the vice. All I want it to do is make it shiny. Probably the best results. I just brushed it on really thin. However, I did find some bristles stuck inside after it had gelled and I could not resist picking them out so I might sand it off some and redo it with foam sponge brushes.

Sparklies abound. They look like little bubbles sticking to where the weave crosses. Did I just mess up when I was laying it up? Does it have something to do with contaminated fiberglass? On each side there is like 1-2 bad layers and that is what you see. Too dry? If I thought the previous layers were too dry I would use less layers on the next step hoping the extra resin would soak down into the previous layers.

One big thing I learned, $50 for a fin is well worth it :stuck_out_tongue: Materials and sandpaper plus the hours…

What do you guys use for the back swivel? It’s some sort of expanding metal tube on the fin I was modeling from.

thanks for that Kai , an entertaining read … [I think you might have edited a few words you might have <span style=“font-style:italic”>said</span> , like when for example you found your fin lying in the dirt !]

I use 40 layers of 6oz for a fin panel for a box , but I’m laying up 5 layers at a time , with polyester resin . So results may vary , with epoxy , and the numbers of layers laid up at a time . [I have yet to make an epoxy resined panel …one day , maybe. ]

The little pin at the back I get from my surf supplies guy …they have brass , and also plastic ones . I guess your home depot may have some metal the right diameter there ?

I like your fin mate , it will be interesting to see a shot of it on your board …[hint hint].

How did you go with drilling the hole for the screw ? [That’s the bit I always get nervous about …one slip / crack …oh , bum ! …"repair time’ ! [been there , wrecked that !]

A drill press is something I keep thinking of getting . Maybe once I start making a few more fin box fins ?

Like you , I would say $50usa is reasonable for a fin …

by the time I’ve bought 5 metres of fibreglass cloth , at least litre of lam resin , 500mls of filler [‘hotcoat’ ] resin , 500mls of gloss resin , roller[s] , brush , tints / pigments …$50usa sounds a fair figure to ask for a homemade fin , I reckon …Especially when you factor in the time to lay it up on glass , the foiling / sanding / drilling / glossing … yep !

It’s FUN though , isn’t it , making your own templates / colours / inlays ?!

well, good on ya , Kai !

keep up the good work mate !

cheers !

ben , west oz …

Kai, its a ‘split roll pin’ available in the little bin drawyer section of your ever lovin’ ACE Hardware. I’ve found 'em both at Markus ACE on 3rd st and Piedmont ACE on Grand Ave.

Did you lay up with a metal roller? That’s the only reliable way to pop all the little air bubbles out - those are what makes your sparklies.

Chip, if you clamp the base firmly in a vice, your screw hole will drill much more reliably. If there is room for the fiberglass to expand - like if you’re holding the fin in a clamp, not a vice - the layers will split apart to accomodate the bit. If you clamp it solid, the bit has to remove material to go in because the layers can’t split apart. And, of course, pilot holes are good too… :slight_smile:

Hey Kai,

It didn’t turn out too badly for a first attempt.

I’ll venture it took much more work than you anticipated.

For the record the time you spend foiling to get all the flat spots out of the fin are really important. Why go to all the bother and not do the whole job? Flat spots on a double foiled fin are dead. Draw a line where you want the vertical cord to be and foil too it. Fair the foil out with a block and 80 grit and finish it out with finer grit paper. The fin will be much faster and more effecient.

No Worries, Rich

No Worries, Rich

kai, there are TONS of articles in the archives on how to make this type of fin, you probably would have been twice as fast, at least, if you spent an hour or so searching and reading before plunging in…

For the best shine gloss it just like you gloss a surfboard. If you don’t know how check the archives.

Also, a small angle grinder with soft pads and 24-80 grit sandpaper will make your foiling a WHOLE lot easier.

On the fin I foiled I did use polyester surfboard resin. The cut out on the right with the yellow resin is also polyester but it’s the cheaper stuff they use for boats and it has a yellow tint to it. It also cures a lot slower and doesn’t wet out as easy though I didn’t get any bubbles in it for some reason.

Benny, I did use a fiberglass roller but only to roll out the dry sheets of glass on top of the wet sheet. The roller makes them lie down real flat without any stretched parts to the weave. I used a squeegee to apply the resin. So the way to get rid of the bubbles is to just press them out? Problem is I don’t think I saw them when I was doing it and it only happened in 2-3 layers out of 40.

The Ace on Grand Ave is real close to me, I’ll check for the pin there, Thanks.

Chipfish, with the screw hole I actually just drilled it by eyeball. The front wasn’t clamped in the vice either. However I do think I drilled it before I cut down the width to fit the slot. I have a shopsmith which can turn into a press too but the thought if it breaking never crossed my mind. Ignorance is bliss.

Halcyon, It did take far longer that I expected. I thought the foiling would go much quicker and maybe it would have it I had used an angle grinder. I thought I remembered people saying they used sanders though. I used a makita random orbital palm sander with 60 grit paper to do the foiling and I know I spent over 5 hours the first time and then tried to add more foil later on when I removed the coat that got dirt in it.

I used to think fins were overpriced, not anymore. Probably took an hour just to cut the fiberglass panels out. Maybe 2-3 to do all the prep and layup. Who knows how many hours sanding.

Blakestah, I still don’t have any gloss resin so I was just planing to put on a very light coat to make it shiny and to cover the exposed fiberglass, then start at a very high grit and then move to polish. I ran into problems with flanges of resin forming at the edges of the fins when I did one side at a time taped off like you would normally do with a board.

I found Halcyon’s thread on foiling. I’m afraid all I have for my angle grinder are grinding wheels and cutting blades and after having some close calls with the dremmel I think I’d be too afraid to do such fine work with it. I can still go back with the 60 grit and sand some more though. Do blocks cut faster than random orbital sanders? The sander did seem to cut the reinforced glass very slowly.

Quote:
I found Halcyon's thread on foiling. I'm afraid all I have for my angle grinder are grinding wheels and cutting blades and after having some close calls with the dremmel I think I'd be too afraid to do such fine work with it. I can still go back with the 60 grit and sand some more though. Do blocks cut faster than random orbital sanders? The sander did seem to cut the reinforced glass very slowly.

Use a 4-4.5 inch angle grinder. Get a soft pad. 24-80 grit sandpaper for foiling. Really, it takes enough work if you start with the right tools, using other tools will really throw a monkey wrench in things.

for the smooth finish you have multiple options. You can use a clear lacquer spray. You can hotcoat it with a brush and polish it some. But that “perfect” look will require a gloss coat (and on a flexing fin it will crack anyway). I’d recommend hotcoating it and polishing it and accepting a sub-pro finish. When you are ready, and get some gloss coat, and polishing pads, it’ll look SWEET.

Single fins are about $8-10 in materials, and for a good non-pro, 1-2 hours of labor. For a beginning DIYer, 10-12 hours. I love riding my own fins, and enjoy making them. With the right tools, lots of pouring over the archives, and some “lesson” fins, you’ll get pretty good quickly. After a half dozen fins, with feedback and guidance from Sways, and the right tools, you’ll make some great fins.

good luck

Found the expanding pins at the Grand Ave Ace btw, took a long time for the guy to understand what I needed and then he had no idea where it was. I happened to accidentally find them. I should have brought a fin along to show him.

I bought three, one was the right size in diameter but the wrong size in length. I’ll have to cut it.

I want to try foiling it more before I add the pin though. I bought a 4 1/2" polypro sanding pad and some heavyduty 60 grit paper. It’s not a foam backed pad but it will take material off fast. I’ve actually been using spray glue cause I don’t have any “sticky.”

Might take a trip to Santa Cruz sometime soon though to get the right stuff at FGH.

“Single fins are about $8-10 in materials,”

???

…wow , you’re lucky !

…here in West Australia , it costs me $50aus minimum , in materials alone , to make an 8"-9" x 5" finbox fin , with a minimum of 3" rake …[being that 4metres of cloth alone [enough for 40 layers ] costs $32aus…

cheers !

ben

Quote:
"Single fins are about $8-10 in materials,"

…here in West Australia , it costs me $50aus minimum , in materials alone , to make an 8"-9" x 5" finbox fin , with a minimum of 3" rake …[being that 4metres of cloth alone [enough for 40 layers ] costs $32aus…

For a 12 inch by 12 inch layup, you need about 36 layers, or 4 yards from the 36 inch 6 oz roll. If you buy by the roll that is about $3/yard. But that will make well more than enough for one fin at $12, I make 3 7.5 inch fins from that.

If you buy 4 yards instead of taking 4 from a bought roll it will increase glass cost about 50% to $16-17.

Then resin…half a quart, about $6-7 for the three fins.

Throw in some miscellaneous pigment and replace a roller now and again etc and it costs a little more, but that’s about it. Maybe replace your sanding pads too…

Fins wholesale for $20-25 in the US. And you can get them done custom for $50-60…

I did bunchs of 3 fins from a 12x12 layup and the costs were about $25 a plate.

Of course, the REAL cost is in foiling time and clean up of the infernal sanding dust. Hack hack hack…

You only use half a quart for a 12x12? I think I used 1 1/2 quarts for an 8x12 panel. I’ll keep better track next time I do it

hi Dave and Kai !

no idea what ‘quarts’ are in mls ,

but I use 60mls of lam resin for every four layers of layup

therefore 10 layups = 600mls of resin , which costs me [a litre] $16.50aus

our cloth is between $6.50-$8 per metre . [And the $6.50 a metre version is not that good a quality , I find]

4 metres therefore costs me a minimum of $26aus.

so , that’s minimum $42.50aus , right there …

[and that’s before a brush , hotcoat resin , tint , pigment , and / or gloss resin is thrown into the mix.]

Rollers ?

$10-15aus a piece . (I use three , if making multi-coloured panels . )

Dave , are you using polyester or epoxy resin for your layups ?

cheers !

ben  

p.s. …although it is pretty time consuming and ‘fiddly’ sometimes, and quite a LOT of work , it is still worth it for me to make my own fibreglass single finbox fins , as (apart from the new F.C.S. ones ! ), fibreglass single fins retail HERE for an average of $120aus , upwards …

I think I used between 48-64 oz for an 8x12 sheet, 40 layers.

Get a roller, you’ll use a lot less resin and get a better strength to weight ratio.

chip, I’ve done both…the polyester is faster, the epoxy stinks a lot less both when doing the layup, and when sanding, but both work out quite similarly in the end. You can even gloss coat an epoxy panel with polyester resin.

that’s good to know about the polyester gloss resin on the epoxy panel , thanks for that !

…Which resin do you prefer , do you find the epoxy fins stronger or lighter or anything ?

I hope to lay up an epoxy fin panel one day [maybe soon !] . I always just figured the extra time for the epoxy to gel / cure / harden might be a bit inconvenient …

cheers !

ben
Quote:
that's good to know about the polyester gloss resin on the epoxy panel , thanks for that !

…Which resin do you prefer , do you find the epoxy fins stronger or lighter or anything ?

I hope to lay up an epoxy fin panel one day [maybe soon !] . I always just figured the extra time for the epoxy to gel / cure / harden might be a bit inconvenient …

My fins don’t break, so strength is not an issue.

On stiffness, any differences in stiffness are pretty minor compared to adding a few more layers of glass to the max camber line. Probably too close to tell the difference in this application, even through epoxy is twice as stiff on paper.

It really comes down to smell and speed. Since I usually laid up panels on day and ground them the next, it was no biggie for me. I’d just cure the epoxy in a small closed room with a space heater, whereas for the poly I’d add a lot of MEKP.

If you gloss poly over epoxy, be sure to clean it with acetone after sanding, and before glossing.

Is this what you are talking about when you say roller? I used it for my multicolored layup the other night and I think it actually created more bubbles.

The first time I used it I only rolled out the cloth dry on the previous layer just to make it lie flat without as much stretching.

This time I used it to try and remove bubbles but while it was good for getting rid of medium to small bubbles it seems to have left tons of the microscopic bubbles (sparklies.)

That looks like a fiberglass roller.

I lay down wax paper. Pour resin, squeegee it around.

Put down cloth. Roll it until saturated.

I repeat this with each layer. When I cannot saturate a layer by rolling, I add more resin and squeegee it around, then roll. Then I go back to adding layers and squeegeeing them until I cannot saturate the glass, then I add more resin.

At the end I roll it over and over and squeegee off the excess. The object is to saturate the glass with the least resin possible (and the highest glass to resin ratio).

With a pressure pull you can make the ratio even higher, but that is extra equipment.

hth

I tapped off the area first making tape walls, then smeared carnuba wax all over the tables and tape. Wet out the flat, lay down the first sheet, then 2-3 sheets at a time with 1 guy squeeging, 1 guy rolling, 1 guy laying down the sheets (I had help last night.)

Looked fine, just like my first fin layup. But when looking at it today it had little tiny bubbles all over, sort of stuck to the cloth weave.

Could it be moisture? It was raining yesterday.

BTW, I used probably 55oz of resin for a 10"x20" panel, 39 layers.