Re: [CAD_CAM_EDM_DRO] Cast resin for a cnc mill design - good idea?

Tom;
Do a search on polymer concrete and you will find a wealth of information on
the subject. PC has good damping properties and is fairly easy to work
with.

I would stay away from polyester resins because it shrinks as it cures
(about 4%) and gives off styrene as it cures. Epoxy is toxic and nasty to
handle until it cures. After that, however, you can eat off it. Epoxy has
practically no shrinkage if it is solvent free and the cure time is often
easier to control. Polyester also has poor secondary bonding properties
making it difficult to pour in stages.

We pay about $36 a gallon for laminating epoxy which is twice the cost of
polyester. Casting epoxies are about $30/gal. The resin is typically
15%-20% of the PC mix so it isn't as bad as it sounds.

After seeing the price for a 60"X120" piece of aluminum toolplate I am
leaning toward PC for the bed of our router table.

Doug