I recently purchased some turning blanks that are 1 1/2 X 1 1/2 X 18" to use for riser material, has anyone ever used this material, or if it is dry, ready to use
No real way of knowing without testing it. Chances are pretty good that if the ends aren't sealed, and it hasn't checked, it has probably been kilm dried, but even then the moisture content can still flucuate. I've used turning blanks for longbow risers without any issues.
I use turning blanks all the time. Most turning blanks are going to be dried before they are put on the shelf for sale unless they are advertised otherwise. Only way to know for sure is with a moisture meter, but there is no real need to go out and buy one. Whoever sold it to you should know if it were air or kiln dried, or still green.
I have used them for riser and tip overlays. I plan on using them to laminate a riser but it will be accent strips only. The ones I get are wax coated.