liambesaw

When it thawed the water from the ice caused it to collapse

It fell apart when it thawed, I was thinking the same thing!

Oh sure, I agree with .3:.7, I'm just saying that paper made no sense, because even at .3:.7 there was significant leaching above 3% copper. I'd just say restricted compared to what? And how do they know? The evidence is missing from the paper.

Yeah but if it says the ratio made the glazes durable with no leaching, but then a few paragraphs later talked about how they leached quite a lot. So that throws the entire premise out the window in my book. I do believe that the most durable glazes keep within that range, but obviously copper had a very large affect on the durability, so their premise that copper would not affect durability is false.

That was my issue with the paper, it contradicts itself quite a few times in the durability section.

Sure! Freezing damage is VERY obvious

Cake decorating ribs have this profile

Yep, and really bad for pvc as well. My tap water from the city is generally extremely soft, 20ppm tds, and I've asked the city about it, but it's river water in the northwest and they are averse to adding minerals. So far so good though, and I have no copper piping in my house, but I know the mains are all probably steel. It'll catch up with them some day.

I do the same. My bisque chucks sit on a shelf because they're kind of a pain, the leather hard ones are best

Well there's also a pretty big difference between metallic copper pipe alloys carrying buffered water and copper oxides and carbonates in glaze. And if your water isn't buffered, well, look at some of the places in the country having some awful problems with lead in the water right now. Acidic tap water is real bad for pipes and solder.

Well they say their test yielded zero copper release but then post that almost 1 gram per liter leached into the acid with their matte glaze at 5% copper cone 6, and only 173 milligrams with 3% copper. I'd say that's quite a bit of durability loss at 5%. But the also say that their matte glaze also was more durable than their glossy, so I am not really computing what they're trying to say, other than copper is safe in glazes because it's not really that toxic.

The issue isn't with the copper itself, it's with the copper causing a softening of the otherwise durable glaze iirc. You could actually eat copper carbonate and live just fine (edit: don't eat copper carbonate)

I'd think tea would be acidic enough to pull copper from a glaze. Barium is a trickier beast that requires special chemistry and firing to be durable. I'd say no to a barium matte at cone 6 oxidation because from my research it is not possible to make this durable.

I just sent an order to the Netherlands, was only 12 mugs but they were quite large! 35lbs, $150 shipping. Shipped in multiple packages was much more expensive! I used heavy duty moving box (double layer corrugated) from home depot as the main box and wrapped each mug in clay box like Marc. Was enough room in the box for a 2 inch layer of peanuts all the way around. The mugs were all taped together in the center. Worked great.

Primary clay is not as plastic as secondary and tertiary clays. For instance, ball clay is secondary and bentonite is tertiary. Fired clay is neither biodegradable nor compostable. There is no biological process that breaks down ceramic, there is no carbon available. The only thing that breaks down ceramic is physical force, ie. erosion, milling. I'd think a soil researching would know these things...

I use a 12 inch lapidary disc fixed to a bat. Cheaper than the pottery specific ones by at least half. If you have amazon or ebay search for 8 inch 240 grit for a cheap one or 12 inch for a pricier one that can do larger feet. I use 60 grit for really taking them down but 240 is a nice smooth finish that won't scratch furniture

Yep throw in the garbage, it is not harmful once hard.

Drier porcelain also takes in throwing water much faster.

For me, if I'm making something to look rustic, I want it to look intentional. To me your photos are a blend of intentional and accidental. If you aren't happy, don't be surprised if someone else isn't happy either.

For a glaze firing maybe leave the top peep out until glowing red and then put it in place. I normally don't leave any peeps out on a glaze firing after 1200⁰f (red glow)

There are more plastic porcelains out there that are easier to deal with. That sounds like a pretty temperamental one.

When dipping you're relying on the bisques ability to absorb water to have the glaze stick. If the clay becomes saturated, the glaze will not be able to stick. So for glazing very thin things, you may need to dip for less time, but multiple layers letting it dry between. Or what usually works for me is to glaze the interior of the vessel, and then wait for it to dry completely and then dip the outside of the vessel. Good luck!

I've read that 5% or under zircopax is stable for cutlery marking. This is for glossy glazes. Satin and matte glazes will cutlery mark at a lower rate, but because of the other chemistry in combination. Alumina matte, quite abrasive on its own, titanium matte less so but still prone.

This depends on whether you can get it to dissolve. It's quite difficult once it goes hard, usually needs some aide like hot lye (sodium hydroxide) which dissolves silica. If it dissolves it will be fine, if not, get some new stuff because hot lye is dangerous and sodium silicate is cheap

I'd get some of the thicker mdf or glue two masonite bats together and then have your friend route a foot into it. The problem may be when it comes to releasing. Plaster would be best so it releases without tearing