Mixing Slip
When mixing slip there are a few considerations to take into effect: Start with about 5 % warm water. Add your deflocculant to the warm water. Because the defocculant is likely to be less then 1% of the recipe, it is important to measure it carefully either by weight or by volume. Beginning with the lightest ingredient mix ingredients one at a time to avoid pancaking later. Every clay/slip will have a clay, a flux (melting agent), a glass maker, and most likely has a filler. Sometimes ingredients will do double duties. Kaolins (porcelains) will be lightest, ball clays next, other clays next, then things like talc, silica, and feldspars are likely to be the heaviest. You can do a simple touch test to determine density. Sieve and add water to get to desired consistency based on your needs. I recommend double sieving at about a 40/60 and 80/100. When recycling slip, its best to dry it out completely then add warm water and double sieve. If you have used a Darvan as your deflocculant, you will not need to add more. If you have used sodium silicate, recycle your slip as above, then test the webbing properties. If it is not webbing properly, add sodium silicate a tiny drop at a time. Go slow with this and be careful not to add too much water until the deflocculation is complete. To avoid this, use a Darvan. Tips: Over deflocculation and under deflocculation look almost the same. Vinegar will cut deflocculation, go slow and if in doubt, revisit it the next day. I have found that slip is best after sitting for a day.
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