Marciemcg Posted November 27, 2018 Report Share Posted November 27, 2018 Was wondering if anyone has had issues with Darvan swirls in slip making a marbleized mark on pieces. It is subtle but I do not use colored glazes on my pieces, so it still shows through. Link to comment Share on other sites More sharing options...
neilestrick Posted November 27, 2018 Report Share Posted November 27, 2018 Do the swirls still show after firing? I think I know what you're talking about, but I've never seen it show up after firing. Link to comment Share on other sites More sharing options...
Marciemcg Posted November 27, 2018 Author Report Share Posted November 27, 2018 Yes, they do show up after firing it is less obvious on the white but even more pronounced on the ones where I color the slip. Initially I thought it might have to do with mixing the stains but it happens on those that aren't mixed as well. Link to comment Share on other sites More sharing options...
Babs Posted November 27, 2018 Report Share Posted November 27, 2018 How much darvan are you using? Maybe need to mix your slip constantly when using. I guess darvan has a sodium silicate base?? If so pos. using too much and not stirring enough... Link to comment Share on other sites More sharing options...
Marciemcg Posted November 27, 2018 Author Report Share Posted November 27, 2018 This was actually pre-mixed slip from Standard. I had them send me a different lot because I thought they had one that had too much in it. I recently made a batch of porcelain slip but haven't fired it yet. I noticed some swirling on that as well. I may try syphoning off the top to see if that works was just wondering if anyone had any thoughts. Link to comment Share on other sites More sharing options...
Babs Posted November 27, 2018 Report Share Posted November 27, 2018 Keep agiating as you apply. Fettle out any thicker areas. Are you brushing or pouring the slip? Are you dipping brush in water? Link to comment Share on other sites More sharing options...
neilestrick Posted November 27, 2018 Report Share Posted November 27, 2018 Slip needs to be stirred a lot. Commercial slip casting operations have mixers that continually stir the slip. Link to comment Share on other sites More sharing options...
Mark C. Posted November 28, 2018 Report Share Posted November 28, 2018 You need to stir the slip more just before using. I ran a slip business for years on the side. We kept the mixer going in barrel while pouring our 60 molds to keep the slip mixed. You are not staring enough before pouring is my guess.Use a power mixer as well to get better mixing. Like a jiffy mixer on a cordless drill. Link to comment Share on other sites More sharing options...
Marciemcg Posted November 29, 2018 Author Report Share Posted November 29, 2018 Thanks for your help - will try stirring a bit more. Link to comment Share on other sites More sharing options...
Babs Posted November 29, 2018 Report Share Posted November 29, 2018 More than a bit, get agitating but not with your brush:-))) Link to comment Share on other sites More sharing options...
tinbucket Posted December 1, 2018 Report Share Posted December 1, 2018 Are you casting or applying slip to thrown pots? I have never heard of using deflocculated (Darvan) slip on leatherhard pots, only for slip casting Link to comment Share on other sites More sharing options...
Babs Posted December 1, 2018 Report Share Posted December 1, 2018 Defloc. Slip will have less water content than non defloc for the same amount of viscosity, thus less shrinkage thus can be applied to leatherhard without as much risk of peeling off before or during bisque firing..so it is handy!too much can turn it to choc pudding sorta Link to comment Share on other sites More sharing options...
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