Preparing Kiln Shelf for Glass Fusing

Primed Kiln Shelf for Fused Glass

When I fuse glass in my kiln, I put the pieces of glass on a kiln shelf. The shelf has to be prepared with a separator, called kiln wash. This prevents the glass from sticking to the shelf when it heats up and fuses together. Sort of like flouring your pastry board before rolling out a pie crust. What you don’t make pie crust?! I don’t either anymore. Preparing the kiln shelf is not a particularly fun thing to do.

I started out by using what all the books said. A putty knife to scrape clean the shelf, and a haik brush to brush on the kiln wash. And then I would brush on 8 coats of the kiln wash. Used to! Not anymore. Now I use a razor to scrape off the old kiln wash  – way more effective than the putty knife. I use a green scouring pad to help with the last bits of kiln wash that sticks on the shelf. I use a cheap chip brush to apply the kiln wash – it doesn’t loose as many hairs. Then I brush on four coats of kiln wash. If I’m being really conservative I’ll put on 6 coats.  And I am way not as meticulous with this as I was when I first started out. When I brush on 6 coats I can for sure get two firings out of the shelf. Anyone have any other kiln shelf prep tips they”d like to share?

5 thoughts on “Preparing Kiln Shelf for Glass Fusing

  1. chaniarts says:

    you don’t need as much or thick of a coat. it’s a separator, so you need only as much as it takes to act as a barrier. the hotter you go, the thicker the layer you need. my normal fusing temp is 1430 so i go on the thin side.

    i typically don’t scrape until i get a ding in the surface; something sticks and i pull up a chunk of the wash. if that’s in an area i can ignore, i still don’t scrape. i just put a couple (at most) of thin layers on what’s already there and it’s good to go.

    also, you don’t have to really scrub off every last bit. as long as it’s smooth, the remains of the previous coat are just covered by the new coat.

    if i’m using fiber paper for any reason, i don’t bother putting new wash under that. the remains of the previous coat are just there for protection against mishaps.

    i have a fiber shelf for bigger things. you can’t scrape those type of shelves, so i usually just add more wash onto whatever is there. if i have a ding in the wash, i either fill with a paste of wash instead of thin layers, or i sweep off my driveway well to get all the gravel off it, then use it as a flat lap to remove old wash and even out the surface again.

  2. Zane says:

    I use the straight edge of a scrap piece of glass to scrap the old kilnwash off of the kiln shelves. Trying to fire as low as I can to get the effect I want, I have been able to fire a surprising number of times before having to redo the kilnwashing of the shelf.

    • Margot says:

      Zane, Thanks! ‘m going to try the glass idea. I’d be thrilled if I could get three firings out of it. May have to experiment with lowering my process temp.

  3. Ursula van Beek says:

    I want to let you know that i prepare my self with something else.
    I put 50% koalin and 50 % plaster together in a tupperware and mix that.
    Than i scatter it on my self and make it flat.
    So your ready and can use it. For several times.
    Every time you miss a little bit, scatter new misx and make flat.
    I make ik flat with an ordenairy paper.
    I hope you understand my englische because i am from holland.

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