fin layups

Ive heard the standard of 30 layers of glass…does that refer to 6oz. or 4oz.

6 oz.

usually 32 layers.

2 parts lam / to 1 part gloss resin to get the best stiffness/flex.

thanks loads!

32 layers of 6 oz isn’t enough unless you don’t roll it effectively. A layer of 6 oz in a tight lam comes out at 0.01 inches thick, a Bahne finbox fin specs at 0.350 inches thick, so 35 layers does it right, I usually do one or two more and sand or machine it down at the end.

And if you are making a big single fin you will want many more layers - like 40 or so. Otherwise you will get too much flex on a 10-11 inch fin.

For thruster fins it is 24-26 layers of 6 oz.

hi Haubush !

were you planning to make glassons , fcs tabbed , or bahne or other boxed fins , please ?

ben

10"cutaways for FINS UNLIMITED boxes.I’ve made a dozen or so but have just sort of made it up as i go along…my technique has been to lay up 30 layers of 6oz. with sanding resin on the side of an old glass aquarium(so they wont stick)I generally use enough cloth to yield 2 to 3 fins.

I then cut them out with a jigsaw(using a new blade for about every fin as they are hard to cut).

I then clamp down to a table and or throw them in a vise and foil them with the same sander i sand boards ith(a milwaukee)using a small diameter hard pad.

They’ve been a bit on the thin side.

my foiling looks great on solid opaque fins but looks awful on multi-color transparent lams…uneven and really shows!

Any tips?

Aloha,

Joe

thanks mate !

I asked , because I got varying results each time , in terms of the base thickness …

One of the reasons why I really like the moulding fin bases approach . Also because that way , I can give thin flexy fins a go [something I’ve wanted to try for ages !] , while still having the right thickness base for bahne / f.u. boxes [ the Aussie equivalent =‘MultiFins’ boxes].

I use 5oz flatweave , and because I lammed as many as 7 layers at a time , and rolled the resin out quite heavily , I often found in the past I was having to use as many as 50 layers [!] of cloth …you can imagine the cost , at $8aus a metre , and $17aus a litre of lam resin . [And , I still filler [“hot”] coated them , before sanding] … For fcs tabbed , I was finding I needed 33 + layers of cloth .

Foiling I do with a grinder . Then handsand , wet and dry , through the grades , then gloss coat .

Some I sand to 800 grit , and don’t bother glossing .

A friend of mine, who is a really good carpenter and a bit of a genius when it comes to making stuff , always says …“it’s all in the finishing” [meaning , taking my time , paying attention to detail , and doing a good job . Something he excels in , and I am not good at …or maybe not comitted enough to ? I always want to get out there and ride it , almost as soon as the resin has gelled …not really that advisable]

ben

intresting…what do you mean by the “mouldled base approach”.

I’ll check the archives.

By the way ,is that your dog with the goggles?..classic!

could you advise me on what sort of grinder you use,i dont know anything about them…hand held,or bench mounted? etc…

Mahalo.

Joe

Quote:

my foiling looks great on solid opaque fins but looks awful on multi-color transparent lams…uneven and really shows!

Any tips?

Aloha,

Joe

The archives have a lot.

The tool of choice is a 4-4.5 inch angle grinder, with a soft pad and a 24-80 grit sandpaper.

I mark the maximal thickness line on my fins, and then foil the rear edge down, then the front edge, then thin the tip. The layers of glass act as guides for the thickness, and it certainly takes a few before it gets decent. But a good gloss job at the end can cover up a mediocre 5 minute foiling job.

Pls search the archives and read a lot a lot.

yep …Dave ['Blakestah '] said it all !!

re : the base moulding ?

here’s a link for you …*

http://www.swaylocks.com/forum/gforum.cgi?do=search_results&search_forum=forum_29&search_type=AND&search_string=fin+base+moulding

well…have fun, mate !

ben

the “archives” are well worth reading …FULL of informative stuff !

  • see the box down the bottom of the “page” ? [ the blank part ,with “search” written next to it ? ] Well , just type in key words , and click search , and you’re up and at 'em …hours of reading awaits you !! [But be warned …it’s addictive !!]