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    When I was at OSU many years ago I polished chunks of crystal and pieces of blown glass. Once I got past the cork wheel to the felt wheel I was told the reason the felt step got that shinny finish was the wheel along with the cerium heated up the surface, I’m guessing like a fire polish. So before I go to the expense of the cork and felt wheels will that remove or reintroduce the film back into a nice shinny piece of glass?

    Thank for your time



    You will need to remove the devit completely or coat the piece with a layer of powdered frit or with a devit agent (do a google search —  you will find products such as spray-a, superspray, and a do-it-yourself solution made of borax). Just firing polishing without treating the surface will likely just cause the devit to spread.

    Dana W.

    Jester’s Baubles Fused Glass Designs

    Stephen Richard

    Unless the piece is flat, fire polishing, even to a matt finish will probably distort the piece as fire polishing occurs at ca. 740C and over.

    Stephen Richard

    blogs at: and



    Thanks so much for that reminder!  I was just cruizing through the posts here, and even after fusing for many years now had a piece ready to refire after sandblasting off the devit…and sure enough it was about to go in without the Spray A …except for your good reminder. :)

    Funny how things happen like that.

    Happy Day!



    Windows listen attentively for the sound of broken glass.


    Cerium oxide, combined with some water and heat, chemically bonds to the glass to fill the ultrafine scratches left behind by the previous abrasive (typically pumice).  That heat – which is a result of friction – may be what you are remembering.  That little bit of warmth (just warm to the touch – too much and you can thermal shock the glass) is a far cry from fire polish temps.

    Helios Kiln Glass Studio


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