dies ist ein Ergebnis von Tests nach einer Meldung über zerbrechende dünne Kato-Streifen zur Herstellung von Carol Blackburns Muschel-Ohrringen.
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und dazu eine Ergänzung, über Color Shifting:
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und hier für die Nicht-Facebookler der Text des 2ten und 3ten Links:

"Hi All;

This week I received an email about Kato cracking! Oh, no, I just hate emails like this. Anyway, Kim had experienced some difficulty with the clay after it was cured (she was making Carol Blackburn's Shell Earrings from her CraftArtEdu class and the strips were cracking when they hadn't before.

I also hate "it didn't happen before"! But clearly this was the case. So, yesterday, I tested and tested and baked and bent and you know what? She was right.

At 300F, the strips were brittle, they did crack. 300? (scratches head). I cure this stuff at 300 and I have not had problems with cracking or breaking….hmmmmm.

So, it was time to find out why and you know, the answer was so simple, I haven't made anything fine or fragile. I've been in a solid, big stuff mode and so, no cracking or breaking. Evidently, I've been in this mode for some time.

Kim's email was a blessing in disguise for I learned something important. Cure Kato between 325 and 340 for maximum durability. I cure for at least 40 minutes (oven is not preheated, it's cold when I begin). 300 is fine for those solid pieces but not so good for fragile work. I hadn't had a problem so I was happy to assume 300 was fine.

The happy ending is this - I recommended Kim re-cure the strips at the higher temps and, lo and behold, bendy, bendy, bendy.

I emailed Tony - hmmm, it's a mystery, the formula hadn't changed one little bit. So, I can't tell you why Kim's first strips bent, then her later strips didn't.

I don't usually monitor my oven and my old oven (it's retired in the garage) tended to spike so often I honestly don't know what temp I was curing at, I set it at 300 but the potential range was huge. So, I'm now using my Farberware (thanks, Darlie) and that sucker holds a temp true. Also have a mercury thermometer so I know my test temps were accurate.

Now, we just have to change the package instructions!

Here are my test earrings with the bendy strips cured at 340F. So, please feel free to pass along this information - might save someone some grief and that'd be very nice!"

3ter Link:

"Okay, so today I cured white at 340F to test how much it changed. I tented some with foil and cured some without. Results were the same, I cured on a tile so even though the clay was tented, it got the full heat from below.

Some color change, now, only you know how much this matters to you. For me, this shift is totally acceptable for my work. I don't need eye popping, white, white, white. And, if I have to choose between white-white and strong-strong, I choose strong-strong. And, how white the color looks also depends on what it's next to. Next to white, white, it looks off white. Next to black, well, then it'd look white.

Also included pic of the violet, turquoise, green mix. There was a very, very slight color shift in the green but none in the other colors.

Note: photos are not enhanced, I didn't lighten or do anything to them other than cropping. I did lightly sand the white, though, primarily to clean it up!"

Der Thread ist ja schon etwas älter.

Hat sich bei Kato inzwischen in der Rezeptur wieder was getan? wird es wieder fester produziert.

Grüße
Stuffl

Liebe Grüße Nicole

liebe Grüße

LG und schöne Ostern!