Best mold sheet to use?

[backyardskier]

me either, but I'm going to try 5 ribs at 18" wide with that hardboard I linked above.

[gerryrig]

I would put more ribs in. My guess is you will get rib indents in the bottoms of your skis. 14 lbs/inch sq~2016 lbs/foot sq.

[troublemaker]

I'd put a rib every 3/4" with aluminum or something like it.

[sammer]

You definitely need to have more ribs.
Even if you skinned it with 3/4 mdf you'd still get print thru.
You can get away with gaps between but you need more support than gaps.
The hardboard you linked to will break between your ribs.
I had an 11" gap between shims under my mold and broke the 3/4' table, permanently deformed it.
I know you don't have 11' gaps but 14psi, even though it doesn't sound like much, is a lot of pressure (over 2000lbs/sqft).

I guess if your attaching your membrane to the top of your mold you can get away with it but you'll want something more substantial for the skin.

sam

[knightsofnii]

Just use a softer, like 5053 .063 aluminum. Seriously. Coat the aluminum with mold release,counter sink your screws along the outer 2 ribs, route a channel in the form under the aluminum sheet for your heat blankets and be done with it. It's the way everyone does it...unless you just want to get weird about it for no reason.

can you explain the part about "route a channel in the form under the aluminum sheet for your heat blanket" ?

just curious, trying to picture this.

[backyardskier]

New game plan yet again, going to make one solid ski mdf mold with .06 aluminum, got a quote today for it and it isn't very pricey. As well did some tests today with .06 pieces I have at work, and if a small dent is in the mold it wont show through the metal which is good. Some of my molds have small router bites in them. Still learning the ropes of ski building there is a lot to it.

[MontuckyMadman]

pretty sure he means rout a recess in the wood topmold not the AL sheet for the blanket.

[Brazen]

^ bingo ). My blankets are, as I recall about .080, so just route that recess to the width of your blanket so everything lays flat when you screw the aluminum down. Alternatively, just leave the outside ribs .080 higher...either way.