Northstar Blue Velvet acting weird??

[Stacy]

I've been making a vortex pendant this morning with NS Blue Velvet as the background colour, at the time I thought it was quite risky as it looks very similar to unobtainium and I know that that is notoriously bad at being encased or covered, but thought i'd give it a go as it would make a great background.

Everything was going great until it came to the twist. I puntied up to my clear rod and began to heat the pendant. When it came to twisting the punty literally slipped off the gather! I tried it several times and each time the punty would do the same.
I'm not sure how to explain it but it was like the punty had been attached with glue. When it came off it even made a sound like heated glue giving way..a kind of squelch!?!?!? 

In the end I manged the twist using some pliers but I still can't work out why teh punty didn't work.
Now although I'm no expert the one thing I've been able to manage have been punties. I know when they are OK and when they have either melted in or arn't strong enough. The connection with these were fine. They were even able to hold the pendant when I made the droop for the loop.

The only thing I can think of is that Blue Velvet is similar to unobtainium and the inclusions caused this but I would have thought the down side would have been cracks not sliding punties???

any ideas?

[garishglobes]

I've never used this colour, but that does sound wierd. I've just looked it up and Northstar say it is a very saturated cobalt colour with the sparkle coming from chrome. I know chrome causes cracking issues, and the way it causes cracking issues is by reacting in a reducing flame to create a microlayer of new COE glass at about 56 (?) which is therefore incompatible with boro.
So...if you had the blue velvet background in a reducing or possibly even a not-oxidising-enough flame, might it have created this microlayer, which would then slide?
Someone once sent me a rod of striking 104COE glass instead of NS Extra Light Yellow and what you describe is quite similar to the result I got. It did feel like it was just sliding, very wierd.

I should add they weren't a regular UK or even European supplier

[Stacy]

Thanks Emma, that's really interesting!

My flame didn't change much during the whole process so in theory the covered glass would have been in a reducing flame also. am I right in thinking that the pendant should crack ?

Its weird but I hope it does now, then I would know why it cracked!!

Also I could feel quite chuffed that I was near to the answer as I thought it might have something to do with the same reason why unobtainium isn't a great encasee. I just didn't know what that was!!

[garishglobes]

Interestingly, Northstar don't have any working notes for NS108-Blue Velvet, wonder if they have found it caused a few problems. It might be worth emailing them for advice.
I would say that the pendant might well crack. I used some GA agua chameleon the other day, got half a dragon made and the *** thing just split in half! I usually avoid the chrome colours but this one is just so pretty and I thought I'd been really careful. Ah well!