Epoxy granite or mineral casting

[Washout]

I've done some composite work and make the odd flight case for people using sheets of a carbon/kevlar/glass mix - the easiest way I have found of getting a glassy smooth finish is to use vacuum infusion onto a rigid sheet of perspex "mould" on a flat surface - you get glassy smooth finish with no bubbles.

Not sure, but you might be able to pull a thin infusion type resin through large sized grains of "rock" of some kind mixed with chopped fibres (I keep all my carbon/kevlar/glass off cuts for this purpose). If you can't vacuum through the aggregate, then pouring into a box mould with a perspex bottom should achieve good results. All the bubbles and crappy surface will be on the top and the shiny flat surface on the bottom, which you can then demould and flip over.

Heat would be my only concern, as large volumes which don't have a matrix of some kind tend to go off with cracks in them, but a few sheets of glass or carbon layered in the mixture should help solve that.

(Eyes up the gallon container of resin on the other side of the cave ;-) ).

Edit - nearly forgot - this link might hel with ratios http://www.talkcomposites.com/11/Res...ge-calculation

[mike mcdermid]

I've done some composite work and make the odd flight case for people using sheets of a carbon/kevlar/glass mix - the easiest way I have found of getting a glassy smooth finish is to use vacuum infusion onto a rigid sheet of perspex "mould" on a flat surface - you get glassy smooth finish with no bubbles.

Not sure, but you might be able to pull a thin infusion type resin through large sized grains of "rock" of some kind mixed with chopped fibres (I keep all my carbon/kevlar/glass off cuts for this purpose). If you can't vacuum through the aggregate, then pouring into a box mould with a perspex bottom should achieve good results. All the bubbles and crappy surface will be on the top and the shiny flat surface on the bottom, which you can then demould and flip over.

Heat would be my only concern, as large volumes which don't have a matrix of some kind tend to go off with cracks in them, but a few sheets of glass or carbon layered in the mixture should help solve that.

(Eyes up the gallon container of resin on the other side of the cave ;-) ).

Edit - nearly forgot - this link might hel with ratios Resin infusion; resin usage calculation

My interest in the bases was piqued because of previous works with carbon gantry mills,there have been discussions for stiffer machines and carbon does the job nicely

My original question was to ascertain if anyone had done this granite thing in the UK
It seems getting on to a company that can answer the questions as they manufacture the machine bases cleared all this up nicely