As it was not windy today i played around in workshop. I have wanted to start reboxing fins as you cant buy decent quick weed fins.

I knocked this unit up. I have the stuff to make the mould.

The arm that holds the leading edge is on a hinge so i can change the angle as i wish. The ali track that hold the fin is the mast track out a my long gone course racing borad from years ago(Windrush XP). The fins(well all of mine do) wedge in nice and tight so minimal clamping is required.

can anyone see and improvements i could make before i pour in the goo to make the rubberised mould(yes Sam i have ripped off your design).

Evets, the fin in the picture will be used to make the mould for reboxing fins.
It should give me a perfect size and angle for the fin base

Good point Elmo. I might look at adding a trailing edge guide as well.

I will also make a jig for pointers. This project is mainly to get a good tuttle mould.

evets said...

Cannot see what else you could add Bender..... maybe a computer controlled positioner to maintain the correct angle
What are you going to do to the fin in the picture?

Also do you modify the foil once you have altered the angle? I have a series of different sized images for a particular foil and use that and a profile gauge (pin gauge) plus car body filler to try to achieve what I hear is a good profile. I measure the fin parallel to the bottom of the board and fill/ rub down to try to get the profile. The result is not pretty as I have not taken to painting yet but seems to work.

evets, the only foil mods that the bent one does on the foil as far as i know,................. is when he runs it into the rocks at hardies
seriously tho i cant speak for bender but i can tell you i just wack mine in the box at 45deg and leave the foil as is,the puritans and experts would probably say different but the things work ok leaning over imo.as long as elmo's snot doesnt hang on the end then its all good
what you describe above sounds too much like hard work,but if your happy with the results,then thats good.

slowboat said...


Old pointers can work great for weed fins. The trick is to find one thats quite stiff to start with, otherwise the geometric twist will kill the performance. They can also be a bit thicker.

So the freeride jobs that are thicker should do the job then?

Thanks for the info Slowboat.
The fin on which I have increased the foil thickness was quite thin and did not produce sufficient lift to get comfortably up wind. Result was very few speed runs as getting upwind took ages.
It is also all I have in that size (about 22cm) so until I get another I wish to try to make it as good as possible.
So far it has given me my pb of 32.5..... hope it will go faster yet!
As for twist, Decrepit demonstrated what you mean with the fin in question....... nothing I can do about it until I get another fin.

keef said...

Bender said...

. can anyone see and improvements i could make before i pour in the goo to make the rubberised mould

hows it going bender have you poored the goo yet and what sort of goo are you useing, if its a two part urathane you will have to vaccume the air out, or if its a one part latex you will have to do a slow build with a brush to avoid airbubbles

Yep the mould has come up a treat. it was a worry as i mixed up the brew and poured it in and found out my maths were wrong as it was a 10mm low tide. i just pushed in a bit of round foam, (sausage like) this diplaced enough goo to bring the level up nicely. i have since shaved the foam off level. All is good.

Now i just need to pluck up the courage to take a jig saw to my new 48cm JP slalom fin and turn it into a weedy. I cant remember what the goo is called. It's like latex rubber stuff(white). Elmo got it for me. it cost $65.

i wil report back after my first attempt

heres a pic of my jig bender,good luck with your project.i've used mine for reheading fins and the two in the pic i've made from scratch.i'm keen to find out what you used [goo] for your moulds,made mine[tiga , power]from polyester resin,there a bit rough but.also keen to find out what is recomended for the fin heads,i used the polyester risin,poked in some matting but concerned they are a bit brittle.

The Goop which bender is using is the Silicone moulding agent which Sam put us onto

The product is called “Elastosil M4503” and I buy it by 1 Kg for 50 bucks (you make 2 moulds medium size with it)

You can find it at *Fibreglass & Resin Sales* they are in Welshpool

111 Kew St, phone 9470 2571 /
web: www.fibreglass-resin-sales.com.au

The release agent which they recommend is in a little pump pack which actually is supposed to condition the silicone as well as act as a release agent, bender recons it's pretty good.

How I mould my fin bases is in some eyes a bit of overkill.

I always keep as much of the fin as possible so that the fin runs along the bottom of the base, this may loose a little length but I think it makes it stronger.
Generally use 3-4 layers of clothe (don't know whether it's 4 or 6 oz).
I use West Systems epoxy with 206 hardener (the slower one)
I mix in 3 heaped teaspoons of glass fibre pulp, into about 50ml of resin.

I've been using fibreglass split moulds which I made after the "axe removal incedent" but they are starting to look a bit sad, seeing the results of Sam's work I will be starting to make silicone moulds this weekend.

Sorry for got to put down

For the F'glass moulds I use 2 coats of release wax then the PVA release agent