Experience Mounting a Foil on an old LF Kite Fish?

kitebot · Since 20 Feb 2007 251 Posts Obsessed

Hi All,

I'm considering mounting a foil with a base plate to an old Liquid Force Kite Fish. I know the foil-specific Foil Fish has reinforced holes through the deck for attaching the foil's mounting plate. I was wondering if anyone else here has done this type of mounting and how they have gone about reinforcing the holes. I'm also curious as how well it has lasted.

Any info is appreciated, thanks!

henjj · Since 09 Dec 2010 25 Posts Spokane

Check with Matt V. I know he has a few LF kite fish boards and he put a foil on one of them.

Matt V · Thu Oct 22, 15 3:55 pm

I kind of did it the long way, but I know I have more rigidity than the new LF Kitefish (Foilfish) production board. Pepi at SecondWind does it with just washers on top, but I did a full "G-Flex" pour for the holes. DO NOT USE STANDARD EPOXY - only use G-Flex! I feel that, by connecting the top layer of glass to the bottom layer, you wind up with less slop due to board flex and get ZERO deck/bottom crush. This is because you are crushing the G-Flex epoxy, not the foam.

My hole locations are the same as was supplied to me from the retailer that I purchased the foil kit from (stock location). Once I have located exactly where the holes were to be, I drilled out to 3/8ths inch. From there, you use a die grinder (think Dremmel on steroids) with a carbide double cut bit to get your holes large enough. If you just keep drilling with larger sized bits, the bit will grab and you will crack the fiberglass on the top or bottom sheet. SO A DIE GRINDER IS NECESSARY! And do not use more than a 3/8-5/16th drill bit on this board or any board as you have the chance of causing some serious tearing/cracking. You can use pretty much any "Christmas tree" die grinder bit that is small enough at the tip to start making your drill holes bigger. Harbor Freight has a pretty good electric die grinder but it will thermal cut out on you if you use it when the air temp is high. A $20 "Christmas tree" carbide bit, that will do many more repairs, is needed to go with the grinder. You can find these at a construction tool supply place or somewhere like Fastenall. I do not like the grinding stones as they almost immediately clog up with gunk when used on plastic containing topsheets like on the Kitefish.

Once I have the hole sized, I used a Dremmel with a 115 or 117 bit to back cut the foam under the top sheet and bottom sheet around the hole.

http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=115

This makes it so the surface fiberglass layer is supported by the G-flex pour. The pour is also completely held in place by the fiberglass top/bottom sheet of the board so it cannot come out.

Then I tape off the bottom and pour solid the holes from the top of the board. After that cures (1 day at least for G-flex), I then remove the tape and layout precise marks for where the holes need to go again. Then I drill, and countersink the holes for the foil hardware.

The countersink was a bit of a problem as I could not find a 90 degree countersink. Metric flat head hardware (supplied with the foil) has a 90 degree lip angle as opposed to an 82 degree lip angle for standard hardware. Not finding those locally, I just used my drill bit sharpening skills and made a counter sink out of 3/4 inch steel rod. If you have the skills to sharpen a drill bit on a bench grinder free hand, you can make your own countersink that will be adequate for this application.

I intend to publish (here) my layout on the quad fin setup I use on these boards along with the specific pour layup steps for my fin re-inforcement or foil attachment points. I need to convert 2 more of these boards to quad fin so I will take pics and notes when I do those. I also have 1 board, my original red one, that I used West System 105/206 epoxy on. This was not the best idea.

Standard epoxies will not work as most epoxies are too brittle and crack. I found that out first with trying to pour some of my own Mini-tuttle fin boxes out of epoxy. I poured my own since I wanted them to be "3 position" adjustable at 1/2inch increments on a Slingshot "Coupe" that I converted to quad from twin. I made a set of plugs (machined aluminum dies) for the longer boxes, coated the plugs with wax, then poured epoxy around them in the board. All of these boxes cracked at the corners after about 1 month of use. But I did like the performance of the board and the locations I used for the fin boxes. The sliding box worked great too, but I need to try that with G-flex.

Now priority is my Kitefish family of boards. I do not use my old surfboards anymore. The kite fish is the do all board for me. I do need to repair my old surfboards and let them make someone else happy, but for me, the Kitefish in a quad-finned configuration is all I need for all non hydrofoiling situations. Then, when I have less wind, I use the my other Kitefish with the hydrofoil.

If they LF ever stops making this board, I will be copying these and building my own Kitefishes.

kitebot · Since 20 Feb 2007 251 Posts Obsessed

Wow Matt, very well done, thank you for taking the time to put together this post. I can pretty safely say that after searching for info like this online above post is the best reference available out there.

All the best!

Matt V · Thu Oct 22, 15 4:23 pm

Hope to do the detailed version soon. But the damn wind keeps blowin!

And I must say it will have to wait till spring if the snow starts to fly anywhere I can get to.

Slappysan · Since 13 Jun 2012 308 Posts Obsessed

I put mine on a twinskim with just big washers, works fine.

Matt V · Fri Oct 23, 15 3:47 pm **Edit!**

I left out 1 major thing in my desciption of the process! I use West System "High Density" filler in the G-flex to add a bit of supposed strength. Maybe it is not doing anything, maybe it is. But only add enough that the G-flex is still runny and will fill the sides of the pour.

Might be a big deal, might not. Sorry for the inaccuracy. Again, hope to do a full write up with pics sometime soon.

As for the twin skim - I have one for sale but I am back in the Midwest waiting for snow now so I would not be able to sell it locally on NWkite. And washers can work fine and have to since Second Wind is letting them out the door like that. I am just a bit overweight so I like my gear to be bomber. And the Twin-Skim or the Kitefish are both even more bomber with a full pour plug. My thing is that I want foot straps on foil board. I cannot make a foiling jibe yet (without touching down), but I can get some ugly landing backrolls to keep the foiling fun. If you are strapless, more power too ya! I just like being able to send it.

Maybe my next project is to mount the foil on the Twin-skim and make some footstrap inserts for it. Kind of scary with the sharper edges on the Twin-skim than the foil fish though. But I know of a few people using plywood as their foiling platform.

stringy · Since 23 Jun 2006 1726 Posts vancouver XTreme Poster

I have helped the local foil army setting up fish boards with my foils. they have worked well even the older red fish from a couple years back. we haven't had to reinforce the fish at all. just drill some holes and I would suggest some larger diameter fender washers to better distribute the load around the holes.
the one thing you are going to need is a transition plate for your baseplate to sit correctly. the fish has a vee hull so I machine a transition plate that allows a flat baseplate to sit against the vee perfectly. if you need this plate, pepi at 2nd wind may have them in his shop. if not send me a pm and I can machine one for ya

kitebot · Since 20 Feb 2007 251 Posts Obsessed

This is great info thanks Jim. Are you still making and selling the Stringy foils? If so are they sold exclusively through 2nd Wind?

Thanks!

wylieflyote · Sun Oct 25, 15 5:36 am

I might be unique, but personally I found the factory drill locations to be too far forward and required too much FF pressure for a balance stance and quicker progression. Ask Jim, and Pepi before drilling, and probably %99 of riders go with factory. But for me it was almost instantly that my ride went from "oh sh*t" to "Hell yeah!"
With mine, I only punched 2 additional holes. So the plate moved about 41/2 back placing the mast and balance more perfectly beneath the arch of your back foot.

Drill and large washers is all you need.

EDIT: Stringy foils are BOMB!

stringy · Since 23 Jun 2006 1726 Posts vancouver XTreme Poster

Matt V · Mon Oct 26, 15 6:54 am

I used to wish that the holes were drilled further back too. That was until I watched the video on the touch down jibe.

https://www.youtube.com/watch?v=Oabf749pMQ0

From a strapped stand point:

Given the video, I am pretty sure that you need that mast forward so you can STAY on the foil through the jibe with the back foot in front of the rear strap. You also need to be able to GET UP on to the foil with the back foot in front of the rear strap. If your mast is to far aft, you will not be able to get on to the foil as you have too much leverage holding it down. Hence the uncomfortable forward position when riding in a straight line.

But my goal is to stay strapped so I can experience the aerial (jumping) aspects of foiling. Jibing is key to this and I am working on it but have not foiled through a jibe. And I hope to maybe even get to some of the freestyle aspects once my skill develops. So stock position is where it will be for me.

Pepi · Mon Oct 26, 15 12:40 pm

Hi guys :

Sorry for not responding until just now.
Yes, we have both the LF Foils and the Stringyfoils in stock at 2nd Wind.
The LF Foils are on the floor display and the Stringyfoils are prepacked at our back counter (we try to keep these packed to reduce floor damage).

RE: Mast placements
Regarding Kips mast placement. Kips board was among one of the very first modified boards from LF and the holes were moved to another location since that point in time.
However, we have found now about a year later that mast placements really do not affect skills development levels that much for most individuals. Honestly, time on the water is the number one asset. If you were to look at most of the foils we are all riding at the Event Site, we each have our straps and masts all in somewhat different locations. Each of us rides specifically well with our foils mounted in manners that meet our skill level needs. Yes, this may sound corny, but it is a reality. There are still many details regarding mast placement that are hard to quantify. This is based on my personal experience directly working with customers, observations of other peoples gear we ride with in the Gorge and testing out other peoples foil set ups.

RE: Drilling holes in the LF Fish boards.
There are no real needs to reinforce the holes due to the boards being of compression molding construction with extra layers of fiberglass utilized just in the construction and the heavily compressed foam core that is not of a water absorbing nature.
We have multiple boards that have been drilled out in many different ways and with different washer plates that are all running strong and have shown no issues of wear or fatigue (I still use the original frankenstein fish that I gave to Stringy almost two years ago which was later used by the LF boys. The board is still running strong and has around a dozen holes in it)
That being said, if you have the time, resources and knowledge to reinforce the holes, there is no reason not to do a quality job like MattV has done (*Seriously impressive work Matt. Also very excellent points on the nature of the appropriate resins for handling the stress and torsion of the mount).
Would love to see some examples of MattV's construction with a surfboard !!

kitebot · Since 20 Feb 2007 251 Posts Obsessed

This is more great info, thanks Pepi!