Positive Flex Fcs Fin Recommendations?

[hart]

Hi Kev, thanks for responding. These are the buggers. You can see they are layed up in three 'layers".

What you are looking at is a clear smoke tint through the bottom one-third lay-up (ie read the trailing edge of the fin) and then a white opaque (ie pigment) followed by a black opaque on top

Each opaque lay-up reqires a hotcoat (fillercoat) between them to preserve the integrity of the laminate (ie the line between the colours) so we have something like 5-6 seperate lay-ups to produce this one panel that you are looking at (and about 30 layers of cloth..dependent on weight of cloth)

It is commonly known in the industry, that opaques DO NOT FLEX (and they are used to stiffen glass) and the only way that BLACK and WHITE can exist in resin..is by an opaque method (meaning solid colour)

All true FLEX panels were layed up as CLEAR (green) or a TINT (ie transparent colour of whatever description)

I think the pigment alters the flex characteristics

Yes it does, because it has NO MEMORY and no memory = a negative flexural characteristic



Hope this is of interest to the thread

hart

[Headwax.]

Hart wroteth

Hope this is of interest to the thread

Well it very certainly is. Thanks for backing up those observations on flex and pigment. Good to get some feedback from someone so well respected in the industry.

I guess I should ask MR whether it was a design choice or a cosmetic choice.... if only I wasn't so shy

But seriously, the flex in those fins is anything but non-dynamic. Guess it says something about craftsmanship and meaningful design.

Bruce, nice to see you posting. Be good waves on the morrow.

retrograds

(BTW Lewis Carroll always makes me feel saner)

[hart]

I guess I should ask MR whether it was a design choice or a cosmetic choice....

Opaques are generally a cosmetic choice..because of their solid nature

You won't see any trapped air beyond the colour, so opaque panels can hide a multitude of sins

hart

(not saying the MR panels have trapped air, of course )

[RMcKnee]

..

[Kev]

thanks Bruce
yes very interesting stuff

I think I can see some of those flaws in the Fins I bought from Shapers recently
well they were cheap
haven't used them yet so perhaps I should go back and exchange for some cleaner looking ones
might require looking through a few sets to get 3 I like the look off


is it possible to buy stock to cut a fin from
I'm keen to DIY a fin or two

probably just a centre fin as then I don't have to make two the same

just to have a bit of fun and to learn something

[frankfqr]

Kev---if your willing to take it as far as cutting out and foiling the template from the blank sheet, with the base to fit a box (that's the complex part). Then take the full learning curve and lay up your own sheet (that's the easy part). The ground work has been spelled out in this forum. And setting aside the advanced suggestions on full compression, each layer can be squeeged out very dry. If you go lightly on the catalyst it will set off and the layers will wet out to a consistent mass. Very rewarding endeavor.

[Kev]

... setting aside the advanced suggestions on full compression...
... go lightly on the catalyst it will set off ...

the compression was the bit I didn't have an alternative on

I guess that brings the last choice of what style of juice and cloth
I was planning to buy the typical repair kit or a slightly larger quantity of the same
perhaps even a Glassing 101 Kit

these things contain
4 ounce cloth
Surfboard Laminating Resin and Filler Resin
the UV Sunbake Solar Resin Additive

so by making one purchase could you have the materials to do repairs and knock up a fin or two ?

I guess if you were to use the UV and did try a compression jig with garage bits and pieces then it

might not go off evenly ?

[RMcKnee]

..

[hart]

And you need to squeegee the bejasus out of the laminate when laying up. Do not be shy.

Sorry mate..a squeegee will do nothing (except tendonitis)

Resin rollers of various radii are necessary

And your other suggestion about using clamps/ compression and UV resin?
(Without light..that stuff won't do sh!t)

And thanks for the hint about board designers

I'll have to google that one myself and pay more attention to this forum

hart

[Bumps]

Hey McKnee,

I get the impression from some of your posts on resins, cloth and laminates you've a bit of knowledge. Industrial? Engineering? or hobby?

All the best

Bumps

[RMcKnee]

..

[Kev]

the UV thing was my doing

not really a suggestion
just a reference to the typical repair kits and glassing kits that would probably contain
4 oz and UV bake stuff

so if one were to make a fin then I would need 6oz and normal resin materials
and then require the things Bruce talked about " rollers and radii"
and it is very likely that with garage based ideas the trapped air would probably be a result

that's why
I'd much prefer to get a workable piece of stock material and then just start cutting and filing etc

a few hour in the garage watching the footy finals
and knock up an unusal shaped fin

googling FGI now
( ... orthophthalic, isophthalic and terephthalic ... )

where is that dictionary

hey wow
thanks for the link
they have a trade centre in Springvale
right near my place

now all I have to do is work out which products I want

[cake]

Is phenolic a good material for making fins?

[frankfqr]

Thanks for being there Hart, I've only used rollers for paint. So I wasn't inclined to go that route, but, if they work-do it. Never tried it, thinking that the sticky solution would pull up on the back side of the roll (not good) while the squegee does nothing but compress. 6oz., good call, squares cut approx. 1 inch over template. 40 layers should yield 1/4 inch thickness. No UV. 50/50 lami. and sanding (unless you want to play with wax? [let's not go there]) No baking pan mould, use 1/4 glass (totally flat) and 1 layer of wax paper. Go real light on the catalyst, it will set off. Believe me, this parts the easy part, worst being the cutting of the squares. MOW---sometimes I think your out there lookin' in, just enjoying the banter Cheers if you are

[stonefish]

i really like the spitfire template , let me know how you like them. ill post current shots of my custom twinfin with finlets design. i left the flex considerations, as it seems to give a soft return when really pushing through a turn. i havnt been able to feel any increase of speed out of a turn from a flexy like i can with a stiffy.