I think it depends on how the software blends the radii. It looked like the tip and tail radius were effecting the region of the profile from the contact point to the tip or tail respectively, and not effecting the profile between these two points. In this case, by increasing the tip and tail radii by the offset from the mold, you only effect these regions.

I am starting to think that since the contact points are offset perpendicularly (straight up) from the horizontal plain the board sits on, you are shaving off the change in the center radius, however you've essentially flattened it.

If you draw a curvy W in Autocad, and then use the offset function a few times to make parallel curves, you can kind of see it happening.

If the center of the profile was dictated by a radius, as is the tip and tail, you could just decrease this center radius by the offset distance, while increasing the radii of the tip and tail by this offset distance, and you should come out with what you are looking for exactly. But, because the center profile is dictated by effective edge and camber, it's a little trickier.

It's virtually negligible. I think when I calculated the changes to these dimensions, it was less than .4 mm on the effective edge, and .6 mm on the camber. Not much you can do with that.

Dante, could you tell me what the clear mold surface material is that you are using? Is it plexiglass, Lexan or another type?

Thanks,
Nathan

It's Lexan (aka Polycarbonate). Plexiglass is too brittle to work as a mold surface.

What thickness is recommended? Also when using lexan as a surface should a mold release agent (like vaseline) be used on the surface?

The surface I use is 3mm thick.

I use TR Mold Release wax but I've heard Partall Paste #2 wax also works well.

To compensate for the build up on top of the mold ribs you can export your profile (.dxf) and in autocad use the offset command (offset by the thickness of the build up) to create the correct shape you'll need. Hope that makes sense. If you don't not only does the overall length get smaller but the radius of the tip and tail gets smaller. The camber is also inaccurate.