New base mold idea

COsurfer · Post by **COsurfer** » Wed Oct 20, 2010 5:52 pm

Thanks DBS. The width of my track is 14". This particular board is a 161=63". Do you think I should have more space vertically, it would be easy to do.

MontuckyMadman · Post by **MontuckyMadman** » Wed Oct 20, 2010 6:32 pm

I know we have been over this time and time again, but beating a dead horse is what I do,
Does the cattrack not transfer the energy/pressure effectively?
It has to be in constant contact?
My bladder is completely flat because I have like no room in my cavity so I don't care but Just making conversation.

doughboyshredder · Post by **doughboyshredder** » Wed Oct 20, 2010 6:49 pm

COsurfer wrote:Thanks DBS. The width of my track is 14". This particular board is a 161=63". Do you think I should have more space vertically, it would be easy to do.

I'm thinking less. Inflate your hose and measure how much of your hose is actually making contact with your cat track. Easy numbers. If you are inflating to 50 psi, but only have 100 square inches of contact then you have 5,000 lbs of pressure transferring to your cat track. All of that will be transferring to your laminate. If your laminate is 200 square inches then the actual pressure that is seen at the laminate is 25 psi.

Montucky, do you get what I'm saying there?
If your cat track is 100 square inches with 1000 lbs of pressure but is only contacting 10 square inches of material then your pressure is 100 psi at that material. (assuming rigid cat track with no deflection.)

A completely flat bladder that isn't allowed to expand vertically is ideal.

Richuk · Post by **Richuk** » Thu Oct 21, 2010 1:48 am

So, it would be helpful to find out what the epoxy content should be when the fibre is saturated - as per manufacturer parameters...maybe. Weighing etc is no great shakes. Once this is known, you don't need to over-pressurise your press, which could be helpful for some

doughboyshredder · Post by **doughboyshredder** » Thu Oct 21, 2010 8:02 am

Richuk wrote:So, it would be helpful to find out what the epoxy content should be when the fibre is saturated - as per manufacturer parameters...maybe. Weighing etc is no great shakes. Once this is known, you don't need to over-pressurise your press, which could be helpful for some

From what I have found there isn't such a number published. More pressure flattens out the fibers more, reducing the voids that would be filled with resin, otherwise. So, I think it's kind of dependent on pressure. You could have all of the fibers saturated, and still have voids with no resin. It sure would be nice to have a definitive answer on what the best ratio is for our purpose, though.

Jekul · Post by **Jekul** » Thu Oct 21, 2010 10:40 am

COsurfer, looks like the rocker/camber shape turned out great. I'll be pressing a pair of skis with my 9mm camber plate this weekend, so I'll try to get some good pictures to see if the MDF changes density. I have pressed 4 pairs of skis/boards on non-cambered mdf and have not seen any indentations caused by the edge...time to press and find out.

krp8128 · Post by **krp8128** » Thu Oct 21, 2010 3:10 pm

You want around 60% fibers to 40% matrix (epoxy). This number varies with material and resin/epoxy.

Epoxy sucks as a structural material, in an ideal layup your loads are carried by the fibers.

Not going to get into the PSI thing again, i feel like we have been there before...

doughboyshredder · Post by **doughboyshredder** » Thu Oct 21, 2010 3:49 pm

we have, but it's a hard concept to grasp, and there are a lot of newer posters on the board, that may have missed the previous conversations on it. They usually tend to be in obscure threads about other topics. (Like this one)

falls · Post by **falls** » Thu Oct 21, 2010 8:31 pm

What's the idea behind this skate banana mold shape?
Camber under each foot for edge hold when carving? Why rocker in between? Floats in powder when the board can return to its pressed shape? Or is it for catchfree turns on hardpack?

COsurfer · Post by **COsurfer** » Fri Oct 22, 2010 5:42 pm

What's the idea behind this skate banana mold shape?
Camber under each foot for edge hold when carving? Why rocker in between? Floats in powder when the board can return to its pressed shape? Or is it for catchfree turns on hardpack?

According to Lib tech it floats in powder and carves on hardpack. I am a little skeptical but thought it would be a fun board to make and test. Here is the final board. I used birds eye maple veneer and a clear top sheet.

Camber:

[/quote]

doughboyshredder · Post by **doughboyshredder** » Fri Oct 22, 2010 10:19 pm

BEAUTIFUL!!!!!!

So stoked for you.

MontuckyMadman · Post by **MontuckyMadman** » Fri Oct 22, 2010 11:37 pm

that's pretty flippin' awesome. How does the plastic topsheet look with the veneer? Bubbles?
Is that duraclear? The natural from skibuilders looks... not good.

really nice work.

COsurfer · Post by **COsurfer** » Sat Oct 23, 2010 10:17 am

Thanks guys, I appreicate it! I have clear top sheet from both crown and skibuilders. I am pretty sure this is the skibuilders clear. No bubbles! The clear top sheet looks great but not as good as a hand finished board. The trade off is a heck of a lot less work. I will probably press another one this week with the crown clear.

MontuckyMadman · Post by **MontuckyMadman** » Sat Oct 23, 2010 12:04 pm

its funny, I thought the mold looked exaggerated. How much do you account for fall in camber/rise if at all?

So that's the "Natural" from skibuilders? In the store now? it looks allot clearer than I have seen it previously on the forum but most of that was vacuum. I guess its hard to tell from your pic how clear it is..

COsurfer · Post by **COsurfer** » Sat Oct 23, 2010 1:39 pm

Yep, I just double checked and I used the ski builders Ptex almost clear. I will press with the crown this week and put them side by side for comparison.

I had no clue what rocker and camber to use so I guessed at 5mm for each. Since the curve is pretty small in length the camber/rocker held pretty well. Based on the appearance it will work great. We should have a ski area open next week to try it out. I designed the whole board in google sketchup.

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New base mold idea