Light rutile

[Gin]

Hi, the recipe cone 6 lists light rutile, this is unavailable to me can I calcination rutile to get light rutile if so what temp and how long to hold? 1000F and hold 30 minutes? 
Thank you

 

 

[Babs]

You can make your dark rutile light by putting it through a bisque firing , I think.

Just need to burn out a few gremlins.

 

[Min]

I haven't calcined dark rutile so can't speak directly to this. From what info I could find it seems the crystal structure of rutile changes at around 650C so I wondered how this would play into both how it would behave in the glaze bucket and when fired.

I emailed Tony Hansen asking if he had any info on calcining temp etc. Given his response I wouldn't go higher than the 1000F with a shallow amount of rutile to test it first with. I would weigh the rutile before and after firing to see what the LOI is then try a test amount of your glaze on a flat test piece and see if you get pinholes or blisters.

Or add a small amount to your regular bisque firing and see how that rutile works too.

If you try this could you let us know how it goes?

Email snippet below.

"Sorry, not sure about this. If it was me I would try calcining at increasing temperatures in my test kiln until the desired color is achieved. Then go higher to see what happens.”

 

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-------8<--------
“Hi Tony,
Question for you about calcined rutile that I'm having a hard time finding an accurate answer to. Do you know the calcination temperature of rutile? From my reading it seems like 650C is the max temp before the titanium undergoes a crystal structure change. Would it be reasonable to expect calcining to 600C would be sufficient or do you know if it can be calcined to a lower temp?"

Edited July 19, 2022 by Min
grammar

[Babs]

@glazenerd

Have you worked on this?

Thanks.

[Gin]

Thank you! will test and let you know.

[glazenerd]

Babs- sorry for the delayed response- not been around much as of late. It’s been 10+ years since I dug around on light/dark rutile. I do recall bisq firing sample up to 1000C- with very little changes. 
 

T

[Babs]

On 8/19/2022 at 8:07 PM, glazenerd said:

Babs- sorry for the delayed response- not been around much as of late. It’s been 10+ years since I dug around on light/dark rutile. I do recall bisq firing sample up to 1000C- with very little changes. 
 

T

Just was asking because I have  used either /or with little noticable diference but I guess it depends on the glaze and the clay it is going on.

[Lauren F]

Hi—

I just replaced my light rutile supply with something called "ceramic rutile" which I was told is the same. 

Back in the studio, the new batch looks significantly darker. Before I run tests, does anyone have any experience with light rutile or ceramic rutile? Are they the same and does the subtle color difference matter?

Thanks! 

[Min]

Rutile is one of those materials that can make or break a glaze, it can vary a lot from batch to batch. I would try it out with a small test batch before using it in a large bucket of glaze. Colour difference might just be your new batch hasn't been calcined.