cleaning molds

How do I get old kiln wash off molds after a few firings and it starts to chip off?

You should be able to get if

You should be able to get if off with a scrub brush.


Jester's Baubles Fused Glass Designs

3m pads

Use the 3m green pads that you get at the supermarket. They won't scratch the mold and they get into most folds in the mold.

Scotch Brite pads

I use the Scotch Brite pads to clean molds, right in the grocery store. You can get them in different degrees of coarseness also, you just don't want to be too aggressive with them as they will scratch the mold if you're not careful. The standard green ones are almost always the ones I use, and do a dandy job! Just start out with a gentle hand.

Think about your slumping temperature

I have not had to re-apply kiln wahs to my moulds for years. If your kiln wash is chipping off after a few firings, you should consider at least two things:

Are you firing higher than you need?  usually 630 - 677C is enough with a longer or shorter soak is enough.

Are you putting a lot of kiln wash on the mould? A thin layer is most often better than a number and thicker layers.

My method of preparation is here:

Stephen Richard

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I am putting a thin layer (I think) of wash. I water it down a lot if that is what you mean. You only apply 1 coat of wash? I am putting 2-3 coats on. If the slump is only to 677c that is more than your slumping schedule is and I pretty much go by your schedules on here.

I am totally self taught so all this is so helpful. The schedules have been the hardest thing.


Proportions of powder to water

I don't know what your proportions are, but the recommended ones are 5 parts water to 1 part powder by volume.  Since I spray my kiln wash on, it is only one layer.  If I brush it on it is two coats - one from centre outwards and the other around from centre outwards.

Stephen Richard

blogs at: and

Heat and Glass

If you are having difficulty with schedules, look at the Bullseye tech note called Heat and Glass.  It has good descriptions of what happens to glass at different temperatures, so you can get a good idea of how to programme your controller to achieve the results you need.

Stephen Richard

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Mold Care

Thank you!  I did not have this lesson very well and have been using too much kiln wash.  You just made my work so much lighter!  There is not much chatter about this as I hoped to find online.



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