Turning spalted wood

[sawmill]

Has any one turned splated wood on the lathe. I have an 18 foot long 7X7 beam and I cut a chunk off from it and made some bud vases for my wife. It turned good but I had a few places where it wanted to tear the grain. I sanded the tear areas out and everything came out alright. Should I run the speed a little faster to prevent this? I am going to play around with the lathe for the next few days as the outside temps is suppose to be -15 to -20 outside.