[JWOOD]

At my last job we did some experiments with replicated surfaces using epoxy based materials. What we found was that we were able to produce replicated surfaces, using a large granite surface plate, with a flatness within .001" over about 3'. The biggest problem we had was the hardness of the surface. We were running an air bearing over the surface. If any grit got on it tended to get stuck in the epoxy and could end up scratching the way or worse the bearing.

[walter]

Schrupphobel72, thank for posting the pictures. That is exactly what I had in mind!

I've got to talk to those guys... Does anyone speak german...

[schrupphobel72]

Walter,i'm German just ask what you want to know!
Schrupphobel

[lgalla]

Mark
I am always saying sand as other posts are saying quartz aggreates.The large rocks looks good on paper but would have high resin demand as the spaces between large aggriates is large.This would not be true if the rocks were like little bricks tightly packed.I only have experience with 50% filler loadings and micro spheres.Example,a box of spheres any size occupies 52%of the box leaving48% voids for the resin demand.We use a mix of different sized spheres to fillin the spaces.I think basicly we are each 50% right.I will mix the sand and we will put in your rocks.We are hear to try to figure out what a good balance is.I have had filler descusions with I think NC Cams quite sometime ago.He perfectly described the reasons for fines and has seen people using E/G.Hopfully he will respond.
Larry

[walter]

Walter,i'm German just ask what you want to know!

What did they put in there..? They may also have some tips on mixing the stuff...

Thanks!