Reclaiming slip casting with Darvan 811

[VirginiaUser]

Hi everyone! Im hoping someone can help me before I start experimenting with reclaim slip. 

I started slip casting with sodium silicate and I'm noticing that my plaster molds are changing on some ways. I've produced a lot of scraps from my previous castings and I'd like to move into using Darvan 811 as the deflocculent for my next batch of casting slip.

Would I be able to use slipped clay scrap that was previously used with sodium silicate as part of making new slip with Darvan 811?

Thank you!!

[Mark C.]

Yes no problem but working with slip have the right tools is always good .

Im a little rusty but I was in a slip business for 10 years and we made many thousands if aria therapy lamps. We had out own slip made in dry for by the ton.we used the trools below to mix it in our slip mixer.

You will need to measure the flow rate (timed with a ford cup) and use a slip hydrometer (one made for slip-they are fat and short) to get it perfect. 

[Jeff Longtin]

As Mark states you should have no problem mixing the two.

If by using the term "sodium silicate" you're referring to the standard "N" brand I would point out that Darvan is a bit better at deflocculating so you can use less. Darvan 7 is the "standard" deflocculant while Darvan 811 is more intended for porcelain and other "hard to deflocculate" clay bodies. 

For many years I was content to use the N brand but in the last few years I have moved to Davan 7. It is an improved sodium silicate. I first encountered 811, in the 80's, when I contacted RT Vanderbilt directly and they strongly recommended 811. They also sent me a sample. I used it, but didn't find it that much better, so I didn't change my process.

[Mark C.]

We used Davan 7 as well even in our porcelain body . I never have used Darvan 811 only read about it. Whatever you use keep it from freezing

[Harold Roberts]

I have used both 7 and 811. RT Vanderbilt seems to always recommend 811 but I find Davan 7 to be better.