I have been watching and sharing with my Swaylockians friends for about a year now. And I thought my Swaylockian friends would like to take a peek into my world of fin making. It all started back when I was a teenager in 1971, when a friend of mine said, " Larry a new surf shop is looking for some part time workers to help out, you should go down and check it out." I was 13 years old just turning 14 at the time. Not to mention that I was a shop class junkie in Jr. High School and enjoyed re-doing old wooden Navy boats with my Dad since I was 7 years old. This was one of the reasons they let me work at the surf shop at that time. My first job was cutting out fins with a jig saw, then learning the other parts of making a fin from beginning to end. Also I learned and built complete surfboards from shaping to resin pin stripping to gloss and polish. Who would know then I would be making fins for the next 37 years of my life to now. WOW, sometime that even blows my mind when I think about it. Well I can go on forever but let’s stay focus on the fin factory. I am going to show you different stages of manufacturing fins alittle each day. Please feel free to ask me any questions and if I can answer them without giving away some hiddens secrets I will. Hope you enjoy the journey. First we will start with Laminating a fin panel, pics to follow.
Here we are starting to laminate a fin panel after preparing the table. We start by rolling out two or three layers of galss at a time.
Right on !!! Larry !!!
I’ll be watchen
After rolling the glass out, you work the resin in by moving end to end of panel, then work the resin side to side. Keep repeating this process until you have reach the required thickness of the panel.
MAHALO
After you have reached the required thickness of the panel, you then add a flood coat or what some may call a sanding coat. Spread the resin out and start to brush it back and forth which will allow the resin to level itself.
Then you move your brush side to side at a rapid pace. After the hot coat settles it should look like the pic at the right. Now you have just completed a fin panel. I will post this panel in a few days with all the fin templates scribed on it before we go to cutting stage. Mahalo,Larry
Cool. Thanks for posting this.
Hey Larry,I’m lovin your work there mate,BUT, if there is one most important aspect that i’ve learn’t
and practised over the past 30 odd years dealing with all sorts of FRP work,in particular surfboard prouction,
is…PREPERATION.
PREPERATION,saves time and money [specially when on ‘piece-rates’]
PREPERATION,More often than not the difference between ‘‘o.k’’ results and a perfect job.I reckon what
youre posting is fantastic for the novice makers out there, but, before venturing further,how about
a brief outline on setting-up and PREPERATION for fin panel demo…?
Hey Larry,
it loos like all your lams are 0/90. any reason you dont alternate layers at 45/45?
Thanks in advance for the rest of this.
Very kind of you to allow us this look into what it takes to make beautiful fins.
I’ve been trying to make fins for a while with less than satisfactory results.
Already saw one difference. The hot coat before foiling.
Another issue for me has been the halo. I guess with a glass fin we won’t see this?
each three layers of glass requires another batch of resin?
in other words are we to assume the panel is set off with many batches?
or perhaps one durn slow one where there is plenny o time to work.
an no roller ?
I been torturing meself with roller clean up unnecessarily?
…ambrose…
Thanks for this, PBLarry – I’ll be watching with interest!
…hello Larry,
lately I did a batch of fins that after foiling presented a bit of bend (in the tip) in the flat side
after cut them from the panel were all flat
I know too much heat in the foiling and grabbing in the corner of the fin can do that
but I start foiling with heavy grits so I dont know exactly the solution
do you experienced something like that from time to time in any batch?
thanx
each three layers of glass requires another batch of resin?in other words are we to assume the panel is set off with many batches?
or perhaps one durn slow one where there is plenny o time to work.
an no roller ?
I been torturing meself with roller clean up unnecessarily?
…ambrose…
A fin stack laid up with a roller is measurably thinner than a fin stack laid up without. You get a higher glass to resin ratio, which generally is regarded as a good thing.
The roller cleanup for me consists of dropping the roller into acetone when I am done. Then I filter the acetone with a coffee filter into the “used” can. With the roller I’ve had no problems with five batches at once, not letting them set before the entire stack is done.
Obviously the pros may know better.
hth.
Larry, …as part of your series here, could you show how a garage guy with a Vise, jig saw(band saw) and File(s), can follow some technique to foil a fin effectively from one of your
panels.
The thing’s that’s always stopped me from even considering foiling fins is the “itch factor.” Especially now that I’m making my boards in our condo bedroom!
nice…
i keep all my work at the office… i shape on the roof, and i glass in the conference room 
libell go to home depot and buy a painters suit they are cheap and go a great job of keeping the itchy out, esp cuz your face is covered with the respirator and goggles
Larry, ...as part of your series here, could you show how a garage guy with a Vise, jig saw(band saw) and File(s), can follow some technique to foil a fin effectively from one of yourpanels.
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Use a metal cutting blade on the jigsaw, and cut out the desired fin shape.
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Get a 4-4.5 inch angle grinder. Remove safety. Remove stone wheel, and put on a soft pad and 24-80 grit paper.
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Get a powerful fan. Put it next to vise.
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Put angle grinder with sandpaper in vise. Turn on the fan and the vise, with the fan blowing air away from you. Wear an old sweatshirt with long sleeve coverage, and leather gloves (I use gardening gloves). Wear eye protection. A dust mask is not a bad idea either, but if you get the fan setup properly, it will not be necessary.
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Hold the fin in your hand, and grind it.
I prefer to mark on the fin the max camber line.
Then I grind the rear edge, marking the thickness by counting the layers I’ve ground down. It only impacts about a half inch to cut in the rear edge.
Then I make passes parallel to the max camber line, and work the foil from the rear edge to the max camber line. Watch the contour lines from the glass layers to make sure it is smooth.
The rear edge should be 3/4 mm thick when done, no thinner.
When the rear foil is done, go to the front, only make passes to keep the leading edge more rounded.
Finish the front edge with sandpaper by hand. It seems to round the foil more easily than the grinder.
Then, go over the entire fin with 200 grit to smooth it out.
For a final finish, the “at home” finmaker will use simple gloss, whereas the pro will use a 2-part spray similar to automotive finish. If it is for personal use you can just hotcoat it instead, and it won’t shine like a glossed or sprayed fin.
If you follow these instructions, you WILL make a high quality fin by the 5th or 6th attempt. By your 20th fin, you will be able to foil a fin in under 20 minutes to a finished spec. A pro can do that in 2-3 minutes, but he, like you, will use a 4-4.5 inch angle grinder with low grit and soft pads. Because that is the “right” tool for making fins.
Wash exposed skin when you are done.