I can't get white

Dear Creators,

I worked with Art Clay Silver until I bought the Prometheus Pro1 kiln.
So I can work with bronze and other clays now.
I found METEOR clays a month ago and received the first samples of metal clays. I found a very interesting material -Glass Clay too. Bought some colors to try. Working with it is really easy and fun.
BUT I can't get wight...
I read all (I think) topics on this forum, tried different ways, but didn't get wight...

There is a picture of my tests:
Pic

1 - the first one. I started from 0 and reached 750 C. And and kept at this temperature for 30 min.
2 - as specified in the recommendation - from 0C to 750C and turned it off right away.
3 - from 0C to 450 c waited 15 min, then I raised the temperature to 800C and turned off.
4 - form 0C to 375C, kept for 30 min, then raised to 550C, kept 30 min, and raised to 770C and turned off.

But the result is not gratifying...

I kindly ask you to share your experience. Maybe I'll found a recipe that would delight...

Thank you in advance!

Hi Paperjoker,
Your picture is "access denied"... You can send a picture by clicking on the icon "send a picture" (envoyer une image) -> just look near the smileys button.

If you have a color problem with glass clays, try to fire your objets on a kiln shelf in the middle of the kiln. In the PRO1 kiln, you have to avoid to fire glass clay directly on the bottom of the kiln. Glass clays need higher temperature in the upper side (like all glass fusing kilns). In the PRO1, the resistance is present on each side except the back side and the front door. So, it's a good idea to fire at an higher level. You'll see that the results will be much better ! Good luck !

PS : No problem to use the simple firing method like your number 2 : "as specified in the recommendation - from 0C to 750C and turned it off right away." 800°C is possible too, it will be more rounded and shiny.

Pour les francophones, j'explique que pour éviter les problèmes de cuisson de la glass clay dans le four PRO1 (problème de couleur), il faut éviter de cuire directement sur la sole du four. En effet, la glass clay ne doit jamais être cuite "par le dessous". Hors, le four PRO1 présente 4 faces chauffantes (fond et porte non chauffants). La sole est donc chauffante, et si on dépose les objets directement sur la sole du four, les décolorations sont inévitables. La solution est de cuire sur une plaque d'enfournement surélevée, ou tout système qui permettra de surélever les objets à cuire au niveau intermédiaire voire supérieur du four, pour s'approcher du plafond chauffant et ainsi obtenir une température plus importante au dessus plutôt qu'en dessous.

Dear Farida,

Thank you very much for help!  I will try with the shelf.
And I will try to send the picture

Thanks for the picture
I confirm that this yellowish color is a problem encountered when the glass clay is fired at the bottom of the PRO1 !
Good luck !

Dear Farida,


Thanks a lot!

I'm trying now...

So....



I lifted the shelf.

Upper test - from 0C to 750C and turned off.
Lower test - from 0C to 375C(30 min), from 375C to 550C (30 min), up to 770C and turned off.


But not white - grey with brown spots...

The kiln shelf you used seems to be a 2,5mm rigid ceramic fiber and seems to be a bad idea for firing a glass clay.
This material is full of binder (containing carbon : this kind of material it's never 100% fiber).
The yellowish color can be caused by the traped carbon (tar) from the glass clay binder itself or from an extern origin like your ceramic rigid blanket.
A metallic box or a grid can be a more neutral shelf (with a very thin ceramic paper if use of a grid)... and I recommand the use of a ceramic shelf covered with a thin layer of Alumine/kaolin mix (that we call Fire Clay, available in our e-boutique), or an home made mini shelf made with Fire Clay (5 mm thick, and 7 cm diameter Fire Clay disc). This is by far the best method to fire de glass clay (and in our workshop, we never use something else !)

Note that the ceramic Fiber as shelf is a strong heat insulator and can probably give some unexpected effects on the firing of the glass clay. We have not made tests in this direction. Ceramic papers don't seems to be very good too. They are thinnest but containing a carbon binder too.

Finally, I think that the thinnest objects can cause more yellowish decolorations troubles than thicker objects

I wish you better results for the future  
To encourage you, know that I've the same Prometheus kiln like yours and I can confirm that it can give (on fire clay uprised discs) very good results with shiny colors.

Thank you Farida for recommendations.
I will try a metal mesh box with the ceramic paper...
And I will purchase Fire Clay for the future!

Yes, I hope it'll help !
Sorry for the trouble
I'll put some free glass clay bags to compensation for loses !
(don't hesitate to remind me this offer in comment in the text box of you future order).