Production Edge Fixing

[flatlander]

Hey everyone,

I'm wondering how manufactures keep the extremely tight fit between edge and base. I know they receive edges pre-bent to tip rads. Line in their old video held 'em with clamps, the Burton Jeremy Jones layup video shows locating fasteners that I assume push the edge snug into the base (top video on http://www.grafsnowboards.com/index.php?url=media). I was wondering if anyone had any thoughts or more details on how this was done. I'd like to achieve a tighter fit with edge and base in my rides.

Interesting side note, has anyone on this forum toured any factories? Just curious.

Thanks from the prairies.

[endre]

they use casettes to hold he edges in, often with magnets to hold them down.

[flatlander]

Thanks. Could you please describe a bit more. The cassettes you're talking isn't the mold track system is it? If the cassette is a mold insert is it tapered such that it provides lateral load from vertical installation? Thanks, just trying to picture whats going on.

cheers.

[Idris]

You need a very very precice mold (casette) and prebent edges to be able to just press the edges into place.

To get a tight fit, lots of clamps and lots of patience. By hand you can get acurate enough to avoid any visable gap. Learning on this one is slow and hard. Just be prepared to take the edge off, scrape off the super glue and try again.

When teaching somone to edge bases it normaly takes them a whole day to do the first one right. Maybee 2 the next day.

[flatlander]

So in essence a recess is machined into the lower mold of net shape, base and first edge laid in, then the second edge is wedged into place so to speak. Correct me if I'm wrong. Thanks again.

[Cadman]

Some of the manufacturers do not glue their edges on. Their molds are designed with magnets so they snap the edges in place.They work very hard at getting the precise edge length correct so when the board is pressed the edge does not separate at the ends and leave a gap. On ski that the edge was not correct, you will see a tiny gap between the ends of the edges. The tolerance between the edge and the cavity opening is somewhere around .010 to .015 inches. Since ptex expands quite a bit, the base material pushes again the edge which pushes against the cavity of the bottom mold when heated in the molding process.
This kind of process requires that the area be climate controlled in many cases since the ptex can expand enough that you can't get the edges to
snap into the cavities.

[flatlander]

Thanks CADMAN. One additional question. So there is in fact a cavity milled out of the bottom mold, depth of which I assume to be edge thickness with vertical walls, and plan shape corresponds to base profile plus edge thickness, would this be correct? Also, is aluminum or steel tooling used from what you've seen?

For a sandwich ski, is the top mold flat, not meaning planar, but that it is a flat surface shaped to the desired upper surface of the ski, or would it be a 3D mold top like a cap ski, which has an upper cavity?

Thanks, I appreciate the help.

[endre]

Both alu and steel is being used, and it can be both milled or put together from two sheets, in the last case the top steel sheet has got the negative shape of the ski cut out from it.

[Cadman]

Some companies do two at a time and the bottom mold is normally machined out in the cavity area about 2mm deep with about 2mm underneath when doing aluminum. The sides have a raised portion to hold the side walls in place. The top is usually a flat piece of 2-3 mm
thick aluminum.