Foam Core Drop Pin

[Niles]

I tried searching for info, but couldn't find anything.

I'd really like to make a drop pin much like Longboard Larry's, and I was wondering if I could do it with a foam core to make it lighter...but I don't know if you can bend the type of foam used for such a thing.

Would this be possible?

[cam75]

I tried searching for info, but couldn't find anything.

I'd really like to make a drop pin much like Longboard Larry's, and I was wondering if I could do it with a foam core to make it lighter...but I don't know if you can bend the type of foam used for such a thing.

Would this be possible?

of course it can be done, look at the carbon evo, the curves in that board are way more radical than the curves in the drop pin.

[Spencer]

from what i know is that they sand down the foam to make the shape not bend it

[cam75]

from what i know is that they sand down the foam to make the shape not bend it

Nah mate, im fairly (99.99%(thats how i do it)) sure positive that the foam is bent under vacuum, sanding the foam into shape would be fairly inprecise and time consuming.

[vj922]

I was going to ask that question, guess i dont need to now.
s So you have a normal foam mould in the bag as well as the foam core? Ithink im beggining to understand this.

Thanks, Rob

[SteveC]

I'd be quite surprised if landy' didn't simply laminate thin foam sheets together in the normal molds.
I assume they reinforce the bolt holes somehow, but that's not hard.

[Niles]

If I were to go ahead with this project, how thick should my foam be? Do you think I could get away with one sheet or should I use a couple thinner pieces and laminate them together?

Last question: would one type of foam be more pliable (read: less likely to crack) than another.

Thanks for the info guys!

[cam75]

If I were to go ahead with this project, how thick should my foam be? Do you think I could get away with one sheet or should I use a couple thinner pieces and laminate them together?

Last question: would one type of foam be more pliable (read: less likely to crack) than another.

Thanks for the info guys!

Well the thickness of the foam is dependent on the density of the foam, ie if you have high density use thinner foam, if you have low density use low density foam.
Again any PVC foam should conform to the shape of your mold under vacuum, provided that your mold does not have really extreme curves.

I just have one mold that the laminate is sucked down onto, seems to do the trick.

[scratch]

This board is being built to test the wedge/dewedge angles (5 & 7degrees) before building a full concrete mold.
The foam is simply scored to assist bending, fitted to a mold under vacuum with lightweight glass, then given its final shape (and inserts for truck mounts), then vacuumed again with structural carbon, and a sexy carbon wrap.

[Niles]

This board is being built to test the wedge/dewedge angles (5 & 7degrees) before building a full concrete mold.
The foam is simply scored to assist bending, fitted to a mold under vacuum with lightweight glass, then given its final shape (and inserts for truck mounts), then vacuumed again with structural carbon, and a sexy carbon wrap.

Sweet. Do you have any more details on construction? It looks like it drops A LOT. I'd love to see future pics.

Thanks for sharing!

[CrisVA]

I'd be quite surprised if landy' didn't simply laminate thin foam sheets together in the normal molds.
I assume they reinforce the bolt holes somehow, but that's not hard.

You can find metal tubes with flanges that can be laminated into a board in just about any hardware store. That
would be the way to go, and just make sure the flanges sit between plies to add to add to the reinforcement. Then you wouldn't have to worry about hardware eating away at the foam.

[scratch]

You can find metal tubes with flanges that can be laminated into a board in just about any hardware store. That
would be the way to go, and just make sure the flanges sit between plies to add to add to the reinforcement. Then you wouldn't have to worry about hardware eating away at the foam.

Tubes with flanges? maybe, I'd guess the bolt/truck stress would be to focused... a "plate" would dissipate the load with less torsional stress/ twist and less chance of failure. It is just as easy to lam in G-10, bakelite or some other composite plate... these materials are meant to work with glass/foam and it is how they mount winches on high performance composite sailboats. I have used G-10 as a drop through plates for pair of foam cores and they performed (& still do) better than wood any day.

[scratch]

Sweet. Do you have any more details on construction? It looks like it drops A LOT. I'd love to see future pics.

Thanks for sharing!

Thanks! This is just one experiment in an ongoing project, really just to test wheelbase & angles... It's still a little funky... My friend Will has taken over cause he wants to race it... I'm onto the redesign but, as it unfolds we'll share the fun.

[CrisVA]

Tubes with flanges? maybe, I'd guess the bolt/truck stress would be to focused... a "plate" would dissipate the load with less torsional stress/ twist and less chance of failure. It is just as easy to lam in G-10, bakelite or some other composite plate... these materials are meant to work with glass/foam and it is how they mount winches on high performance composite sailboats. I have used G-10 as a drop through plates for pair of foam cores and they performed (& still do) better than wood any day.

It's not the face you should be worried about with foam core boards. If you make the board correctly the faces have plenty of strength; it's the bolts passing through that can wear away at the composite. Other composite boards I have seen have had tubes passing through, or had the drilled holes filled with resin and then redrilled. The flanges would just make it easier.

Not that you couldn't stick something extra in there on the face, but the bolt passing through is an area that needs to be reinforced first assuming you make the rest of the board correctly.

[scratch]

The G-10 was used under the face... It's a solid block of glass with a tensile strength that can't be beat

[CrisVA]

The G-10 was used under the face... It's a solid block of glass with a tensile strength that can't be beat

Ah, well my bad then. I tried looking it up prior to writing the post and could only find the winches, which made me think it was surface mounted.

[thomasberg]

hey scratch, is that board 100% foam and carbon? it looks like there isn't an ounce of wood in it anywhere.