Some "experts" claim that machine bases must be cast with quartz fill
whereas others say granite is the only choice. The one thing nearly all
agree on is that the resin content should be between 5-10% of the total
mass.
Now for a caveat. The vast research done by Philly and a few others is not
without merit. Those who build ruling engines and diamond turning machines
benefit from this knowledge base. It's just not applicable to a hobby
machine with rolled ballscrews and ABEC1 bearings. Spectral and thermal
response of the base is the least of problems here.
Start with a true 100% solids epoxy and add your choice of moisture free
stone fill. Again, some claim fine powder is best and others say a variety
of powder and agregate sizes should be used.
At $50 a gallon (10.5 pounds) for epoxy you get up to 200 pounds of casting
mix. With filler you should have about thirty cents a pound in the mix.
That's about the price of steel.
Doug
