Future Finbox Installation AFTER glass Roberts White Diamond

Hello again everyone.  It’s been a while since I’ve posted anything, but thought I’d post something else I just finished.  I searched the archives and didn’t find any step by step topics that had photos of a Future Fin Box install after laminating and hotcoat.  There were quite a few posts that described how to do it but I thought for any newbies thinking of doing it themselves this might be useful to them.  I am not an expert by any means and this is my first Future install so please feel free to make suggestions or additions to the post should I make any glaring errors.  I didn’t have the installation kit and after having completed it there are a few things I would have done differently but all in all I’m pretty happy with how it came out.

I recenty picked up a 5’8" Roberts White Diamond with Futures setup as a thruster and though I love how it rides with the GAM/G1000 setup I had been wondering what it would be like as a quad.  Since getting my feet wet doing my Carbon Fiber Biscuit Board I figured I could manage this myself too.  I was going to go with Probox’s but decided since there were already Futures installed, I’d stick with them. 

First I called the guys over at Roberts to ask what dimensions would work best with the bottom/rail shape, super cool bunch of people over there.  They recommended 4 3/4" up from the tail, 3 3/8" from the stringer, 1/8" toe in and a 2 degree outward cant.

I picked up a set of 3/4" Rail boxes and got to it.  First I taped off the rear of the board and drew out the measurement lines as well as the shape of the Future fin box.  I’d originally made myself a template but realized afterwards that it was too thin for the router bits lengths I had relative to the depth of cuts I’d be making so I ended up freehanding the cuts with the router and cleaning it up with some files afterwards.  Having the install kit would have made it much faster and cleaner but I didn’t want to pay $120 for it.




 

Next I cut out “Racetrack” shapes of 4 ounce fiberglass cloth, one that was 3/4" offset from the finbox flange shape and another larger Racetrack shape that was 1 1/2".  I layered it this way to make the feathering in of the hotcoat surface layer a bit easier to make sure I could get a relatively flat surface transition to the existing bottom surface.  Check out the Futures website and watch the video on how to do the install, they suggest cutting a slot down the center.  This really helped in preventing the “tenting” and avoiding air bubbles that I’d read about (even though I still got airbubbles, it’s tough to not get airbubbles)

Then mix up a batch of catalyzed laminating resin mixed with a gap filler to help bind the finbox to the foam underneath and also fill in any gaps.  I’ve heard you can also use cutup fiberglass too.  Brush it into the hole and push the finbox down into the hole until the resin starts to gush up out of the seams.  Wipe off any excess.  I then pressed the box down at a slight angle to include the 2 degree cant, tilting outward toward the rails, and used masking tape to hold it in position while the resin hardened.  Make sure the edges of the flange don’t come up past the surface and stay either flush of just below the surface.




First I cut in the center deep section with the router at a total depth of 20mm, 16mm for the center and 2mm for the flange and an additional 2mm for the 2 degree cant angle.  Then I router cut in the outer flange area at a depth of 4mm, 2mm for the flange and 2mm for the cant angle.  After I made the second cut, I pulled the tape off and found that my lines weren’t all that straight so I ended up cleaning up the edges by hand with some files.  To make sure I was still lining up the boxes correctly, I drew in with pencil the measurements and centerline.  Had I to do it again, I might have just skipped taping it altogether and just drew my dimensions directly onto the bottom of the board.  Test fit the finbox in the hole and make sure the flange sits just below flush of the surface (if you’re going to put cant angle in, if not, then just make it flush with the surface).






After the resin dried I noticed one of the finboxes was set in slightly deeper than the other and on one side I had a stepped ledge that I knew would give me some problems later with the glass.  The angles looked right with the fins installed so I was okay with this as it wasn’t going to affect performance.  More on this later. 



Cut some masking tape into strips and cover up the finbox hole and screwhole.  I did the 3/4" offset racetrack fiberglass shape first.  Spread some catalyzed resin all over the top of the finbox and surrounding area with your fingertip, less resin is better.  I used a brush to stipple the cloth to wet it out.  I found trying to do this with my fingertip just moved the cloth around too much.  The brush helped also to get rid of the airbubbles trapped underneath. 




Then while the resin from the first layer is still wet, apply the 1 1/2" offset racetrack fiberglass cloth over it and wet it out with more catalized resin.  Again, less is more you want the cloth to disappear but have both layers as thin as possible, adding more resin to make it thick is not a good thing here.  Stipple (dab) the brush to wet out the cloth and get rid of any airbubbles trapped underneath. 





Next up Hotcoat.  This time I used UV catalyzed resin and spread it out over the fiberglass layers just enough so that I couldn’t see the weave of the cloth anymore.  You don’t want to lay it on too thick here because you’re just going to be sanding it down later.  The end goal is to get this to blend into the existing surface of the board with as little a difference in height as possible without sanding into the fiberglass you just laid.  It was at this stage that I realized how many air bubbles I still had under the glass and the huge/long air bubble that stepped section I mentioned before (to get the 2 degree cant angle) created.  More on how I fixed this later.




You can’t have air bubbles underneath the glass as it will weaken the bond and eventually crack, so I had to do a little surgery with a syringe and an exacto blade to fill the air bubble with resin.  All along one edge of the finbox I had a long air bubble from the step down I mentioned would be an issue.  The trick to fill this is to pop a hole with the exacto blade at one end of the air pocket and then put the syringe tip into the hole, then pop another hole with the exacto blade on the opposite side of the air pocket as an exhaust port.  This way when you inject the resin into the air pocket, the air trapped inside has somewhere to go out of.  Do the same with all airbubbles.





I took the board out into the sun to let the UV resin cure for about 5 minutes.  Then I grabbed a rubber sanding block with 80 grit sandpaper and started grinding off the highest protruding section of the finbox, eventually sanding away the masking tape and exposing the finbox hole.  I then switched to 120 grit and started sanding down the hotcoat, going slowly and watching for signs of sanding into the fiberglass cloth.  If you start to see the weave pattern, stop.  You don’t want to sand through your fiberglass cloth.  Continue to feather out the surface, trying to get the new surface to blend flush with the existing surface.  I had a couple of low spots that I filled in with UV cure resin, took it out into the sun to cure, then continued to sand to get the surfaces flush.




I continued to feather out the edges using 220 grit sandpaper around the perimeter edges of where my 1 1/2" offset racetrack cloth layer was, using center/outward strokes.  I did this until I couldn’t see any edges of where the new layer of fiberglass and resin was.  It bugged that the edges/gaps around the finboxes were not consistent from left to right and a few other things, but the end result came out pretty good.







Now the best part, lately around Los Angeles we’ve been getting a couple overlapping S/SW swells and Topanga has been lighting up with chest to shoulder high waves.  I took the White Diamond out with Vector 2 438/375 quads and what a difference in feel.  I love riding it as a quad!  It rockets through the flats and still holds really well on hard bottom turns.  It feels much looser to me now too.  I didn’t get to surf it as long as I’d hoped as the sun was going down and just 2 weeks ago there was a 12 ft great white spotted at Topanga so I didn’t want to push my luck.  This whole week is supposed to be good so I can’t wait to get used to the quad setup.  I’m stoked on how versatile this board is.

I hope this info helps someone in the future!

Hey swanny,

As far as Futures quads go, I believe they offer the rear side fins in both 1/2" and 3/4" options… That being said, you can install the 1/2" “X” boxes and probably be OK… Make sure you check before you start routing though.

Hope this helps, let me know if you have any questions.

Hi Swaylockers,

 

Bumping this thread up since I am planning to do the same thing and this was a great step by step thread. I had a question, though as my board is really thin in the back. The back of my board is just barely over 3/4" thick. I believe futures side fins are 3/4" deep. This being the case, do you think I can follow through with routing fins out? Curently its a thruster, that will be converted to a quad.