THIS IS BASED IN MY OWN EXPERIENCE — do your own testing!
I've seen a paid tutorial by a very well-known expert that uses and recommends crystal clear powder (BE 1401-0008) on his original firings -- first time a project goes into the kiln. But in my case when I was trying to FIX DEVIT (could this be the difference?), crystal clear powder gave me very frustrating results. I was doing the same thing I had always done. Was it me or the powder?
I turned to the awesome Bullseye Glass Community on Facebook, and the commentary from others I received there was not to use crystal clear, but instead just "plain" clear, BE 1101-0008. Here's the post: https://www.facebook.com/groups/BullseyeGlassCommunity/permalink/1076699992846684
I switched and it worked perfectly! Here's the original BE tip on this, too. (Which can be confusing because the recommended products featured on this page include crystal clear... so maybe both work?)
https://www.bullseyeglass.com/methods-ideas/quicktip-use-bullseye-clear-powder-to-fix-surface-flaws.html
I think more testing is in order... I won’t give up on crystal clear but the clear worked in a snap.
Here are other details in the video
Other BE glass used: Peacock (1176); Clear 3 mm tekta
Firing schedules:
First full fuse:
300-1100-30
100-1225-90
600-1490-15
9999-900-90
100-600-0
Subsequent attempts to add powder and fix devit:
300-1225-30
600-1490-15
9999-900-90
100-600-0
Slump (unknown platter mold -- bought it used, no maker markings)
150-1200-60 (slow ramp just because I wanted to be conservative)
9999-900-120 (two hours, again, just being conservative)
100-600-0