The Welding Tips and Tricks Podcast from a couple weeks ago had a rep
from Walter Abrasives on:

"For this weeks episode we had a great time chatting with Jonathan
Douville again from Walter Surface Technologies about Grinding
Abrasives. Jody wasn't able to join us for this episode so we asked
Jason Hurst of Worksbyahurst on Instagram to join in in his place. We
all learned a lot about the different types of Abrasives..."

Direct download:

http://traffic.libsyn.com/wttpodcast/Ep_80.mp3

all their podcasts:

http://wttpodcast.libsyn.com/

or find it on your favorite podcast/music provider.

There was a lot of interesting info there. A lot more involved than I
ever thought. It's 70 minutes long but well worth the listen if you run
any kind of cutting, grinding, sanding... disks for yourself and/or
business.

--
Leon Fisk
Grand Rapids MI/Zone 5b