Freeze and fuse powder color change

[LondonShard]

Hi Everyone,
I've been experimenting with a freeze and fuse technique using CMC as a binder.  I have a silione mould of a swan-- put a small amount of Crystal Clear Bullseye powder so it will be on the surface of the finished piece, then a few sprinkles of dichroic frit and clear powder, and the remainder with a white opaque.  Fired on my normal fuse cycle (tack fuse).  The swan came out opaque light gray.  The mold details were good, so I think the temperature was Ok.  Any ideas on why it came out this colour? 
Thanks

[Flyingcheesetoastie]

Residue from the binder burning off?  I don't use anything but water in my freeze & fuse, but it can still be difficult to get a pure white if you have any contaminants in your water.

[LondonShard]

Could be... The mix was CMC and distilled water.  This was my first try with CMC gel. Isn't this a pretty commonly used binder?

[Flyingcheesetoastie]

Also, did you let the water wick out of the pieces into the kiln shelf, as sometimes this boiling directly from the glass powder can cause discolouration.

[LondonShard]

Hmmm... Hadn't thought of that!  Thanks!  Will do some more experimenting!

[Flyingcheesetoastie]

You should leave your pieces at least an hour on the kiln batt before starting your kiln but longer if they are larger.  They can be inside the kiln so you don't nee to worry about knocking them but it's quite an important stage to the process.

[LondonShard]

Thanks for the tip!  I had just popped them into the kiln
Will let you know how the next batch turns out in a few days!