Making my own Hydrofoil Board Mold

These are the steps I took to make my own Hydrofoil Board Mold. You can use anything you like for the board (Hydrofoil  board, Wakeboard, wakesurf board, etc). The process is basically the same. Although this isn’t the cheapest process in the world to make your own board, there are many benefits –

· Weight - My hydrofoil board dropped from 12+ lbs to 6lbs 10oz. Although one wouldn’t think that is a lot of weight, you can tell instantly just by picking up the foil assembly.

· Strength – I was having problems with my old board cracking around the tower area. I won’t know for awhile, but have a feeling this one should last a lot longer.

· Customization – you can setup/change the board in whatever manner you choose.

So with all this being said, this is MY procedure. I would highly suggest you NOT follow it. I am not a composite expert, and don’t claim to be one on TV. I take no responsibility if you do this yourself. I’m sure there are many things I did wrong, and there are probably better ways to accomplish this. But this is how I shaved 6lbs from my board.

• Remove everything from the top of the board (foot beds, foot stays, tower, d-nuts under tower, etc)
• Wax the whole board at least 3 times with Carnuba release wax – wait an hour between each coat.
• You want to wax both sides in case epoxy makes it’s way to the top of the board when you start laying up the mold – you don’t want to ruin your old board.
• Put clear packing tape on the top edge of the board all the way around.
• The Tape will help keep any epoxy from sticking to the old board – just in case. It’s on the top of the board, so it doesn’t have to look good since I am only making a mold of the bottom and sides. It doesn’t matter if there are creases/folds in the tape.
• Put black electrical tape around the sides of the board (I used white elect. tape).
• I used a filler material to fill the gaps between the board and the flange – this tape will keep it from sticking to the side of the board, and make it easier to remove from the mold when we are finished. I only put one layer around the board, but after the first mold, I would probably put 2 strips along the sides to make it thicker and protect more of the sides from getting any filler on them.
• Cut a piece of stiff polypro white paneling (1/4” thick from Menards) about 4” wider than the top of the board all the way around. This is the flange of the mold and Here's a pic of the flange and board together.
• Cut small piece of Polypro that will be attached to the front tip of the old board to raise up the flange a little.
  (Picture)
• The front of the board is not thick enough for the 1” Nomex, so I needed to add some depth now, or it would be a pain later
• Use a heat gun to warm up the polypro paneling so that it conforms to the shape of the ski – once it cools, it will remain in that shape. Only heat the back side of the polypro, not the smooth side.
• Attach polypro paneling to the board with double-sided duct tape (Wal Mart) and 2 screws that go in the foot bed holes.
• Make sure the smooth surface is facing towards the bottom of the board.
• Once everything is attached, use some fiberglass reinforced body filler (Wal-Mart) to fill in the gaps all the way around the board.
• There will be a LARGE gap at the tip of the board to increase the depth in that area of the mold. I tried to get the body filler as smooth as possible, but didn’t worry too much. I’ll end up sanding the final mold later after it’s popped off the board.
• I used a plastic putty knife and rounded one of the corners, then just slid that all around the board to have a uniform curved transition between the board and the flange.
• After that sets up (doesn’t take long for the body filler – 15 minutes, work pretty fast), sand a little. Try not to damage the flange (polypro paneling) when sanding. Once again, the final mold will be sanded, so just get the rough edges smooth for now.
• Fill in the t-bar oval and the d-nut holes with non-hardening modelers clay - definitely want to plug those holes.
• Wax, wax, wax, wax, wax – and when I got tired, I waxed again.
• Trust me, it’s difficult to get the board to release from the mold, so wax A LOT (I put about 10 coats of wax on the flange and bottom side of the board) Might be overkill, but I wanted to get my board out of the mold.
• Remember to wait an hour between coats of wax

• Getting ready to layup the fiberglass.
• Put on 2 or 3 coats of PVA (light coats) with an air paint sprayer at 90-100psi
• Wait about 30-60 minutes between coats
• I had to water down the PVA a little due to the low humidity here. It kept “spider webbing” when I sprayed it.
• After the last coat has dried for at least 60 minutes (but not overnight), it’s time for the first batch of epoxy.
• I used polyester resin on my first mold – The rest of my molds I used epoxy.  Epoxy is a little more expensive, but SOOOO much easier to work with! Doesn’t smell NEAR as bad, has a much greater time to work with the material before it sets up, is most likely stronger, and just better stuff. I did use a mask and gloves throughout the whole process. (Here's a pic of the lab)

• Mix the epoxy according to the manufacturers specs (if you weigh your epoxy, check the books – 2:1 or 3:1 ratios are for volume – weight is usually less for the hardener.
• Note – pay close attention to air temps and cure times. I tried Aeropoxy in a 60-65 degree garage, and it never cured (or at least took way too long) I ended up using heat lamps on the mold because I didn't want to wait a week for the epoxy to dry.  I ended up TRASHING my old board since the board expanded and trashed the mold and the board. Had to find a different board and started all over.
• Mix up a little epoxy and add silica or some type of thickener to make a peanut-butter like paste that will be gooped on the d-nut indents and the t-bar oval indent. (here's a pic of the finished area) Also put this all along the edge of the board where the board meets the flange. It will make it easier to get the 2oz fabric to lay down properly without air bubbles since you don’t have such a severe angle between the board and the flange. Smooth out with a putty knife/spatula or something similar.
• Mix more epoxy for the first coat
• Add a colored pigment (black, orange or brown – something other than white so you can see it well)
• You CANNOT use polyester based Gelcoat for this step – you either need an Epoxy based gelcoat, or just color your own epoxy. Polyester gelcoat will not stick well to epoxy, and will most likely pull up when you release the board from the mold. Epoxy with brown pigment worked great for me.
• Brush on the first layer of colored epoxy pretty thick. You’ll think your board will never look the same, but as long as you waxed it well, and used PVA, it will come out better than when you started since it will now be waxed. J
• Lay down the first layer of 2oz fabric.
• DO NOT USE ANYTHING HEAVIER FOR THE FIRST FEW LAYERS (unless you want to make another mold) You won’t get the air bubbles out, even if you vacuum bag it. Make sure it lays nice and flat. I cut a slit at the tip of the board from the flange to the tip of the board to make one side lay over the other side to get rid of air bubbles. (I did this on all the layers)
• Make sure to wet out completely, and remove all air bubbles. Any air bubbles at this layer will translate into a void in the mold which is a real pain to fix later.
• Lay up 2^nd layer of 2oz
• Lay up layer of 4oz
• Vacuum bag for 8 hours (depending on temps) (NO HEAT LAMPS!!!!!)  (Pic of the vacuum pump)

• From now on, you do not need any pigment in the epoxy.
• Lay up another 4 oz
• Lay up a 9oz
• Lay up another 9oz
• Vacuum bag – 8 hours

• Spread a HEAVY coat of epoxy over the mold and then lay up the coremat material (stiffens the mold by adding thickness without adding a lot of weight – fiberglasssupply.com)
• The core mat will not lay well around the curves, so you will need to vacuum bag this layer for sure.
• Lay up a 9oz – make sure to wet out completely – the coremat is like a sponge, and will soak up some of the resin
• Lay up a final 9oz
• Vacuum bag – 8 hours

With the mold I used for the first board, I stopped there. It ended up that the mold twisted slightly when heated for the new board. I went back in and added 4 more layers of 9oz to stiffen up the flanges and sides for the next boards I will be making.

• Let cure for at least 3 days before you begin to remove the board from the mold.

• Remove the polypro paneling flange from the top of the board
• Use a screwdriver to remove the fiberglass body filler around the board edge.
• Should pop up pretty easily since you put packing tape around the top of the board and electrical tape around the sides of the board.  It will probably break into pieces, but that's fine.
• Use a rubber mallet to pound on the mold and try to break the board free.
• Most likely it will not break free, but hopefully will allow a very small screwdriver, plastic putty knife or something to be placed between the tip of the board and the mold. It’s easier to pry the tip up (front of board) then to try to get something behind the rear of the board.
• Keep prying up on the board (try not to damage the board), and insert bigger screwdrivers/wedges in the gaps until you get the board to pop. It took me about half of the board being pried up before the board finally popped from the mold.
• Inspect your work of art and be proud that you didn’t have to make 4 molds to get to this step like some of us.

• I had a few minor imperfections in the surface of the mold, and I wanted a very good mold, so:
• Sand the board with some medium sandpaper, and then some fine sandpaper
• Mix epoxy and silica and fill in the imperfections to get a flat surface,
• Mix up epoxy and brush a thin coat of epoxy over the top of the whole mold.
• After the epoxy cures for a full day under a heat lamp, sand the surface coat (very fine sandpaper) to make a very smooth, very clean surface for the mold.
• Mold is finished. Let stand for a few days before using the mold.
• On to making the board