Wow! Great experiment. You saved me a bunch time, work and material. I was about to do the same test. Now I know the the expected results. Thank you kent for this ceramics mythbusting.
I've had occasional crazing similar to what you're showing where there's an interface between bisqued clay, decorative slip and glaze. The slip was Pilcher's White (supposedly a wide ranging multi-cone firable slip). So, time for some more testing, but I'm suspecting a bit of a fit issue where there are three different substances with subtle COE differences, which ultimately showed in the clear glaze (Jess' 2167 clear - clayshare). Also, I wonder if anything would have behaved differently if you'd used Darvan instead of water to thin-out your slip to make it more paintable. Useful video! Thanks!!!
Thanks Bob. I think you're right about the COE. I've been having more crazing with my clear glaze and think I need to ramp up the glass formers (from my limited understanding of glaze chemistry). As far as using Darvan - that's an interesting idea. For my large batches of slip I don't notice a huge sensitivity to the amount (once I have enough). It might be interesting to see if in a small batch it does get more fluid.
@@PotterybyKent Re: COE and "good fit." - I've found DigitalFire to be a good resource. Ultimately, it seems it's the glass formers that are the most important factor when it comes to crazing. Re: Decorative slip - When I make my Decoratve slip I've been using my bone dry scrap ^5-6 B-mix rehydrated at 1000g clay to 600g water, which yields a very thick slip which I use as a base. If I want something more "paintable" I add about a 1/4-1/2 teaspoon of Darvan to 400g of slip. The transformation is pretty amazing. Previous experiments with painting leatherhard pieces with a slip containing more water have sometime led to a piece crumbling in a few minutes; this is less likely to happen when using a deflocculant. FWIW I also have Sodium Silicate on hand, but have been not using it so much as it can shorten the life of my molds. One last thought: I recently went to a 0.6mm nozzle for one of my 3D printers; it's proved to be a good choice in terms of shortened print times, and I can still get pretty detailed mold masters at 0.15mm resolution.
Monique at Nu Kua uses mason stains, slip and water to make her underglazes, and they work fine. Cutting costs is a great idea - this stuff gets expensive!
Yes technically an underglaze can be applied on bisque ware and this cannot. But applying colored slip like this is a good way to add color. As far as costs, the easiest solution there is actually to make more valuable pots to bring in more revenue!
I really love and interested in your works but ihave no idea of what are those materials being used and where can I purchase ! Thank you so much if you can share it to me ! I am from Cebu ,Phillipi es and a senior citizen and love to try it anfd for my extra earnings ! Thank you so much!
Thanks! I'm not sure I can help directly. But what I'd suggest is finding some sort of local class or studio and talk with them. Or even a local potter who can give you pointers.
That would depend on the relative costs of your ingredients, and kiln firing costs. My kiln is HUGE so often I can pack in more pots, especially in a bisque firing where I don't need to worry about most of them fusing together (like I would in a glaze firing).
Wow! Great experiment. You saved me a bunch time, work and material. I was about to do the same test. Now I know the the expected results. Thank you kent for this ceramics mythbusting.
Sure thing! It's not quite the same as underglaze, but depending on the effect you want it can work well.
I've had occasional crazing similar to what you're showing where there's an interface between bisqued clay, decorative slip and glaze. The slip was Pilcher's White (supposedly a wide ranging multi-cone firable slip). So, time for some more testing, but I'm suspecting a bit of a fit issue where there are three different substances with subtle COE differences, which ultimately showed in the clear glaze (Jess' 2167 clear - clayshare). Also, I wonder if anything would have behaved differently if you'd used Darvan instead of water to thin-out your slip to make it more paintable. Useful video! Thanks!!!
Thanks Bob. I think you're right about the COE. I've been having more crazing with my clear glaze and think I need to ramp up the glass formers (from my limited understanding of glaze chemistry). As far as using Darvan - that's an interesting idea. For my large batches of slip I don't notice a huge sensitivity to the amount (once I have enough). It might be interesting to see if in a small batch it does get more fluid.
@@PotterybyKent Re: COE and "good fit." - I've found DigitalFire to be a good resource. Ultimately, it seems it's the glass formers that are the most important factor when it comes to crazing.
Re: Decorative slip - When I make my Decoratve slip I've been using my bone dry scrap ^5-6 B-mix rehydrated at 1000g clay to 600g water, which yields a very thick slip which I use as a base. If I want something more "paintable" I add about a 1/4-1/2 teaspoon of Darvan to 400g of slip. The transformation is pretty amazing. Previous experiments with painting leatherhard pieces with a slip containing more water have sometime led to a piece crumbling in a few minutes; this is less likely to happen when using a deflocculant. FWIW I also have Sodium Silicate on hand, but have been not using it so much as it can shorten the life of my molds. One last thought: I recently went to a 0.6mm nozzle for one of my 3D printers; it's proved to be a good choice in terms of shortened print times, and I can still get pretty detailed mold masters at 0.15mm resolution.
Thank you. I love the way you explain things. By the way you have a very nice voice!
Thanks so much!
I have a big boy question, i wanna make my own underglaze out of a clay that fires red. Do you think that will affect the fired colour?
It might and really depends on the amount of pigment in the slip you apply to the surface and how thick it goes on.
Monique at Nu Kua uses mason stains, slip and water to make her underglazes, and they work fine. Cutting costs is a great idea - this stuff gets expensive!
Yes technically an underglaze can be applied on bisque ware and this cannot. But applying colored slip like this is a good way to add color. As far as costs, the easiest solution there is actually to make more valuable pots to bring in more revenue!
Beautiful
Thank you
I really love and interested in your works but ihave no idea of what are those materials being used and where can I purchase ! Thank you so much if you can share it to me ! I am from Cebu ,Phillipi es and a senior citizen and love to try it anfd for my extra earnings ! Thank you so much!
Cebu , Phillpines!
Thanks! I'm not sure I can help directly. But what I'd suggest is finding some sort of local class or studio and talk with them. Or even a local potter who can give you pointers.
Very Good and Perfect
interesting video, thanks for sharing! Also, what is that tape you use (and where to find)? Thanks very much!
Sure thing. I got the tape from amazon - amzn.to/3Cqmp29
@@PotterybyKent Thanks for your helpful and fast reply!
Very nice
Thanks!
Slip is authentic to pot making. Is not the poor man's glaze?
Slip is clay - so ends up with a different surface finish than glaze
Good but if you have Ro bisque fire again , it is not any saving
That would depend on the relative costs of your ingredients, and kiln firing costs. My kiln is HUGE so often I can pack in more pots, especially in a bisque firing where I don't need to worry about most of them fusing together (like I would in a glaze firing).
😍