Those bases are beauties. Wondering if you went the Poly or Epoxy route? Poly shrinks so much (3 percent) that I imagine having to hotcoat the bases later in order to “shim” them up properly. (Plus epoxy is so strong).
I like the dividers you used. It would save me some more effort. I’ll probably use modelling clay (plasticine) as stoppers.
How close was your fit?
(remember you can increase/decrease by removing/adding masking tape to your mold)
I used general purpose resin …goes on blue, changes to pink when gelled . It took ages [hours] to gel , because it was a cool night …about 6 degreesC [42F] in Grant’s garage.
I wish it HAD shrunk …we made the base gap a bit too wide .
Still , that will be easily remedied when we screw together a base , we will put the masking tape in place before putting a fin box fin in the mould to check the spacing is right .
How many layers of masking tape do you use George ? It seemed to peel off from the glass with no hassles , even WITHOUT any release agent / wax , which was good to know.
I’ll probably pigment the bases from now on , just so as a friend said it will look a bit more like " I wonder how they do that ?" [and possibly , give a more “professional-looking finish”, hopefully!]
To be continued …
ben
p.s. - here’s some [more “pulled-back”] shots , showing the workbench of Grant’s that we do this stuff on …[thanks Grant !]
check side pieces are perfectly perpendicular to the base [a very good reason for using a wooden base !]
make sure all wood is true , and sanded smooth and even
definately use a wood base …resin will leak through a masking tape base. [as we found out]
take straws out BEFORE resin sets overnight…d’oh ! d’oh ! etc… [resin work in the morning , preferably, for that gel time reason ! ]
try to get the fin’s gap right first time [we didn’t!]
Don’t push the fin all the way to / through the base [not with masking tape for a base anyway .]
As mentioned previously , I’ll pigment the bases from now on , I think. Generally , I’ll try to match the colour of the fin , BUT… a contrasting base could look good , too…
[George , do you have a photo of your grey-based red fin you mentioned previously ?]
just like Hicksy inferred, I should have told you that the base gets tape, as well as both sidewalls of the mold.
This way, you can adjust the dimensions of your mold by adding/subtracting tape layers. I have about 6 basic layers of tape on each of the side bits. This tape also acts as a gasket, sealing the sides of the mold to the base.
I use epoxy (recommeded) and the stuff usually takes the outer layer of the mold’s tape with it. I just re-line the mold and I’m ready for the next fin set. Not sure if Polyester will be strong enough; (you can tell me the verdict on this one).
Lastly, I had the idea of molding shapes into the process. For example, the holes for the pin and screw. It might be worth investigating the use of clay (plasicine) in the exact size needed. These sacrifical molds can be left the entire
time and then they can be picked out and the holes scrubbed clean.
I imagine that you can make clay “dowels” by rolling the stuff by hand and then finishing by rolling the clay between two flat plates separated by a couple of appropriately-sized wood dowels. Then carefully chop off stock as you need.
I’ll try to locate that fin (red fin w/grey base) so I can get a pic of it. It was for some fins I did for the LokBox system.
…I was just commenting to Grant sunday arvo “how good it would be if we could mould the tab bit at the same time” . [ I will give that a go on my next one .]
eureka, yeah i think their is a cheap way to mold the lokbox fin base. remember berts contour mat? the silicon rubber i used did not work for me but i found a new use. actually i think you can even use the silicon for bathrooms…and no wax requiered as the resin dosn’t stick to it.
salu2
uzzi
still need some refinemend to hold the angles etc.
here’s MY first attempt at a couple of wood core single fins, in a moulded base , to fit a fins unlimited type box.
A big ‘’ thank you ! " to you , George, for generously sharing your technique with us all !
fins inserted into 200mls of polyester resin [12" wood mould box , with a “divider " fitted at 6”]
Another view , showing divider between fins…
Ben, Nice set-up, like your jig set-ups. George I checked out your stuff on the molding thread pretty Slick! I like how you guys think out of the BOX!!!(-; Mahalo,Larry
