What Alumilite resin is best for machining?

While all of Alumilite's rigid resins can be machined, sanded, and tapped, we do recommend Replicator 400 as a first recommendation. It is a filled resin with a 6-8 minute open time and machines beautifully. Avoid mixing in excess air by steadily mixing for a minute or two and scrape the sides & bottom ensuring to mix it thoroughly.