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I have been using Excaliber dental plaster, which has an 18,000 psi and a 0.09% expansion in the white color. I stay clear of the gray as it has bubble issues. However, recently I picked up a box of Merlin's Magic and will be giving that a thorough testing. It has a 14,000 psi with a 0.06% expansion. There seems to be a consensus that Merlin's Magic is easier to work with and it has been more than a decade since I originally gave it a try.
Where do I get it from?
Only one place, Clint Sales and Mfg. for nearly 15 years I have done business with them and they have -never- let me down. Not only is their prices on dental plaster one of the best out there, they have always had the best rates when it comes to shipping. When you are buying 50 pound boxes of dental plaster that means something. Having cast more than a ton (yes...literally more than 2,000 lbs.) of Hirst Arts blocks I appreciate prompt service, consistent quality plaster, and reasonable prices.