pre-fire dusty kilnwash

[aaa8]

I've noticed this with my latest batch of kilnwash. I'll apply it and let it dry, but thereafter even the slightest touch will result in a fine residue of kilnwash "dust" left on the hands, glass, whatever comes into contact with it. Before firing and after firing. I know post-fire such dust is to be expected, but is the pre-fire dustiness normal? It seems to work just fine, no glass stuck to the shelf. But I know this stuff can be dangerous and want to avoid as much airborn particles as I can. I moved away from thinfire just for that purpose, but I wonder if this kiln wash is having the same effect before I even fire it!

I'm not using bullseye kilnwash. It's some no-name stuff bought off a website. Also, sometimes I'll reuse kilnwash, in the sense that the bucket I used to apply will have some powder leftover after all the water has evaporated, and then I'll just add more water to reconsititute it for the next application. Could this be my problem? I wonder if the evaporation process changes the chemical nature of wash...

Thanks for your help!

[Bert Weiss]

Kilnwashes have 2 basic ingredients, which sometimes overlap. There is a separator (alumina hydrate) and a binder. In the case of Bullseye they use EPK, which is a clay with a high alumina content. The clay holds the wash in place. Primo is different, it has no clay, it uses an organic binder that burns up, making it easy to remove after a firing.

You should be able to wipe the dried wash and smooth it out a little. It is normal for some to come loose.

I'll take a guess and say that the wash you describe does not have much binder left in it. If the maker, mixed ingredients in a large batch, it is possible that your bag does not have a high enough percentage of binder. Or, your expectations for sticking are too high.

[rosanna gusler]

throw some cmc or other binder in there for 'green strength'. elmers glue works in a pinch. expensive though.rosanna

[aaa8]

Thanks! This makes me feel a lot better. I'll try adding some CMC to the next batch. Good idea.