Commercial Slip

[Christine]

Hello everyone

 

I recently bought some ready-made casting slip which I'm using with home-made plaster moulds to cast a series of boxes. Even though the slip was incredibly cheap (main reason for the purchase!), old habits die hard and I'm recycling the pour-off from the moulds back into the slip bucket and am noticing that the mix is getting thicker - maybe an obvious thing when I think about it, but my question is this:

 

Shall I add water to the slip to bring it back to what looks like the correct consistency? Can I keep doing this - there'll be at least half the original quantity left when I've finished this current project

 

I have only ever made my own casting slip in the past - in comparatively very small quantities and to a fairly concise recipe. Will my adding water upset the chemistry? and will it matter?

 

Thanks in advance for any advice and opinions - I'm so grateful to belong to such a supportive and interesting forum

 

Christine

[scoobydoozie]

Hi, Christine,

 

I've done cast ceramics before and had a pouring table, etc. Ideally, you should have a viscosity cup to check the slip for consistency/viscosity. I have always added water to get the correct viscosity and have never had an issue. All the ceramic studios that I know of that pour greenware also do the same. So, no issue that I'm aware of.

[neilestrick]

Casting slips contain deflocculants, which make them fluid without adding as much water, so they set faster and shrink less. If your slip is thickening, you can just add water to thin it, but only do a little bit at a time. The deflocculants will make a little water go a long way.

[Christine]

Thank you so much for your replies

 

I shall add water with impunity .... well, maybe just a drop at a time!

 

Christine