Nice project!
I stiffen boat moulds using offcuts of foam laid on the mould surface and glassing over them to create a framework of “girders”. I glass on ply afterwards as the mould is already stiff, the ply is cut so that the finishes mould site level on the floor or a table…
Speaking of flex… I made a set of about twenty 9’1"s with varying flex patterns. The boards came from the same molds, and were identical in weight and dimensions. The difference in the way they surfed was HUGE.
I cant get enough of these types of posts Kendall…your insight is the best…even better than Burger’s…your comments are stimulating, but still down to earth.
Are you going to be putting a vent in the board? Is it even necessary?
That mold looks really good so far. This should be another interesting thread.
Making a USA made popout of a Chinese made board. I love the irony of it.
Consider 1lb. EPS for the support ribs. As mentioned earlier it will help isolate the compression/tension loads that the top and bottom skins will have. Maybe Gorilla Glue them in place. Here a pic of a broken Salomon board as a visual, very similar to what you’re working on:
more pictures here:
Are you going to be putting a vent in the board? Is it even necessary?
Vents are only necessary if you take the board in the sun, put it in or on your car, or take it on an airplane. If you live ON the beach, and can get your board to the water without it getting hot first, then you can do without the plug. Endlesswinter probably wouldn’t need a plug on his hollow board. Anywhere else the answer is put one in.
I cleaned the mold up a little bit
I finished the frame for the bottom half and I also sprayed my mold release. I will lay the fiberglass to make the bottom mold in a few days
Great thread, can’t wait to see more.
Nice. I’m just glad that someone is building surfboards more complicated than the one’s I’m building. ha.
WM
Have you considered some type of isogrid for the skins of this hollow board. After following your previous build, I feel like you would be the most accepting of an untested (on surfboards) design.
http://composite.about.com/library/weekly/aa980525.htm
but you could have done the same 5 second google search.
Here is the bottom half of the mold. I still need to mount each half of the mold in rigid boxes
I built wooden boxes around each mold and wet sanded it.
I made my first test section.
I think the lack of responses is because we’re all completely blown away here, I know I am. Suddenly SurfTech doesn’t look so much of a threat.
At the start of the thread, you mentioned the parting board, and then, POOF, all of a sudden you had a mold made. Did I miss something? How do you account for the thickness of the parting board when creating the molds? Are you going for a finish right out of the mold? If so, could you please elaborate on your technique for avoiding pin airs in the outer surface of the fabric?
The parting board thickness does not matter because it was destroyed before the second half of the mold was made. The first half of the mold serves as a parting board for the second half. I hope to have a perfect finish out of the molds. My final design allows a board to be made without any exterior sanding at all. The interior flange must be sanded in order to bond with the other half. I dont know if there will be pin holes or not, the mold is painted with resin first, then the wet fabric is placed on top. Hopefully, painting the mold first will solve the problem.
“My final design allows a board to be made without any exterior sanding at all.”
Wow! I can’t wait to see this! This may sound dumb as hell, but how does the ‘interior flange’ work? So you mean the board will come out of the mold with both halves joined? Again, I think this is awesome!
JSS
No. The top half and bottom half will be made seprately. Then they will be joined later. The joint is internal. There will be a seam across the side of the board all the way around.
So, is the interior flange built into one half of the board, and will achieve a kind of ‘press fit’ when both halves are joined?
JSS
yes. I will pop this part out of the bag in a few hours and post a pic so you can see
Well… The test section looks like crap. Hindsight is 20 20, here are my mistakes.
I did not prep the mold properly. I thought I could get away with only PVA mold release. It worked well molding poly resin to poly gelcoat, but it does not work so great when epoxy is molded poly gelcoat. The part was very hard to pull out. I waxed the whole mold with part-all and I will spray with PVA. I know this will work.
I got anxious and I pulled the test section out too early before it had hardened. I damaged the test section while pulling it out.
When I brushed the mold with epoxy, I should have waited for the epoxy to tack before laying the carbon. The texture of the carbon can be felt on the surface.
My schedule was 6 oz carbon, 5 mm divinycell, 6 oz carbon. This is not strong enough. I will change to 2 layers of 6 oz carbon, 5 mm divinycell, 6 oz carbon with carbon tube reenforcement on the inside.