Since searching and the re-formatting in the Archives makes some things really confusing, I made a Word doc out of these really cool posts for my own use in thinking about making a flex fin, and thought I’d throw it up for anyone else to see in a more readable format–not claiming these as mine, all credit is due the guys–just wanted to share
I’m still looking for more stuff about flex fins (somewhere I saw one from Matt about 25 layers of glass, I thought) and dealing with fin box fittings–
All credit and gratitude to the original posters given inline, of course.
Re: Suncure fin panels
Posted: Mar 16, 2002, 6:12 PM
Post # 9 of 11 ( 167 views)
I use a 3/4" piece of plywood as a work surface, cover it with wax paper, pieced together with masking tape works fine.
Decide on your dimensions, I use 15" x 24" , it works with 30" cloth well.
Cut your cloth up and stack it in sheets of 5 layers. I made my last ones for FCS boxes so your layer count will vary with the boxes you are using.
I believe 30 layers of 6 oz. cloth works out to proper fit for Fins Unlimited type long box. FCS- 25 layers, and I used every bit of 56 oz. of suncure UV catalyzed resin which I tinted blue.
Layup 5 layers at a time, working ALL the air out and really concentrate on wetting all the cloth out. Five more and so on until you’re finished. No reason to hurry if you have your lighting setup right.
I walked it out into the sun (last one was a 40 degree day, try that with catalyst!) Within minutes it was curing to the point I could lift the panel up to cool it some.
I was cutting fins within a couple of hours. I use straight lam resin, no wax solution and do the cutout and foiling like this.
You can finish them with a brush job using a hoatcoat mix also with UV if you want. Really check on the actual thickness you need for the box you are working with, regarding cloth layers.
Oversize is better than undersize, it’s easy to thin them down for a close fit in whatever box you are using them in.
I believe Jim Phillips posted some good numbers in the archives now about Bahne’s specs for layup of box fins. Hope that helps.
Tom Sterne
cutting fin from lay up panel
Posted: Aug 23, 2002, 8:17 AM
Post # 1 of 12 ( 45 views)
the last time i layed up a glass fin panel, i let the panel cure and then scored a cut line on it from the template, and attacked it with a sabre (jig) saw…it was a pretty miserable experience since i didn’t have a diamond blade. i went through about 5 steel blades and it took friggin’ forever! today i layed up a pretty thick panel,3/8"+, and when it got to medium gel stage (more or less) i put my template on the panel and cut the fin out with a box cutter. like buttah, baby! took about a minute. i’m not saying that i’m mr. inventor or anything, but i hadn’t seen this mentioned yet so i’m sharing. …
36 layers of 6 oz. …i did a careful initial pass with the blade that might have gone 10 layers deep or so, and that was my guide for the second pass, all the way through to the plate glass below. i didn’t mix real hot, it’s 90 degrees down here g’day
Ramon
Hey Ramon! That is a great tip. I did a big panel last Fall for making old 5x7 wide base Fish fins. I used the same method you did with a sabre saw. It was slow but not that bad as mine were layered to fit FCS rather than Bahne boxes. What did work surpisingly well for me was to use SunCure catalyzed resin. I was able to use a light tint color and ended up with a ready to cut sheet in short order. Hmmmm…all I would have to do is do a short UV exposure to start the cure, cut while still pliable then re-expose for final curing. Great idea mano!
Tom Sterne
Re: Fin Foiling -- Methods????
Posted: Jul 14, 2002, 10:38 PM
Post # 3 of 15 ( 277 views) [In reply to]
…I start the rough foil with a 4" disc grinder with a 36 grit disc…After that, I’ll move to an orbital sander, starting with 50 grit progressing to 100 grit…I might hand sand the leading & trailing edges…Be sure not to work one side too much…A little bit on one side , flip to the other, etc…That ill keep your mistakes smaller and more easily correctable…
I put a drop of hot glue between the two fins to hold them together while grinding/sanding…After I’m finished I’ll slip a putty knife between them to seperate the fins…
Paul Jensen