Using Oxides On Clear Glaze.

[Rex Johnson]

Doing some experimentation.

 

I'm using some Laguna Clay WC-520 #16 Transparent (all-purpose clear gloss glaze which fires from Cone 5 to 10.)

as a base over several ^5 bodies including Santa Fe, RSMC,WC-401 B-Mix, and ^10 Soldate.

 

I've done one firing and found some inconsistency with the oxides vitrifying with the clear, mostly due to imconsistent mixers and brushing and colder spots in the kiln.

 

I'm doing some upgrades to the to my gas kiln now (bagwall, insulation, etc).

 

I want to just use red iron oxide, cobalt oxide, and rutile and fire at least to ^5 with a reduction to get everything matured.

 

What's the water to oxide recipe? What consistency am I looking for for brushing?

[Rex Johnson]

Any input on this?

 

I'm wondering if using the oxides under the glaze might be a better idea than on top of the clear glaze.

Not trying to especially get a clear pattern, more just looking for a blending of color.

[Marcia Selsor]

I would take a few plastic cups and fill them 1/2 way with your clear glaze.

This would be about 50 grams of dry glaze already in water. Then, add your rutile about 2.5 grams (5%), iron 5-10% or 2.5-5 grams and then cobalt carb. about 1%.

Or, mix the colorants in a slip.

Marcia

[KarenMcPherson]

Any input on this?

 

I'm wondering if using the oxides under the glaze might be a better idea than on top of the clear glaze.

Not trying to especially get a clear pattern, more just looking for a blending of color.

 

 

YES under the glaze-- think of the clear glaze as a lotion- and the pot as dry skin. Once you put the lotion on, it is hard to put colorant "in" to the skin. You want to put the colorants on first and then seal over it with the clear glaze. I usually mix Colorant with a flux and clay, or just flux (i.e Gerstley Borate or whatever feldspar you use)- You could also start with 50/50 Gerstley Borate/EPK. Then you add your colorant- you can find charts out there that tell you how much of each to add, i.e. for iron you could add anywhere from 2% to 8%, but for cobalt you would add .2 to .5% and get effects. Just depends on the strength of the colorant and they are all different. You can also add a little barium or lithium (both toxic) to get some cool effects (and brighter colors- I usually fire lower range, not sure how these would do midrange). Small amounts. Experiement. Keep track, take notes.

Then put up some pictures!

[KarenMcPherson]

In response to your consistency question, I go anywhere from cream to a wash- depends on the effect. SOunds like you want to "blend" the colors- I would say do multiple coats of a lighter wash.

k

[Rex Johnson]

Thanks for the input folks.

Yes, looking to add as a free-form pattern (stripes) that will flux enough to not bubble and over color the glaze. Pattern retention isn't optimum but some control over it would be nice. Will report later on this.

[Rex Johnson]

Medium-green and Turquoise stains with an iron oxide stripe under the Laguna #16 ^5-^10 Clear 20 minute reduction. These over RSMC^5 and Santa Fe^5 Laguna clays.

It was a bit over fired as you can see by the ^4/5/5.5/6 conepack.

There was alot of crazing going on, I suspect due to the stains...

 

 

These are a Shino ^5-^6 over white Rod's Bod ^5 from Laguna on the bowls. Bowl on left has turquoise stain, io stripe, it worked well enough without crazing.

 

The fluted shapes (beloe) are RSMC with the Shino , io stripe under the Shino, wax stripe over.

[Deb Evans]

Do you tap the damper in and reduce air for your reduction ? > pic shows no reduction on bottom shelves.

Anyway

you'd be better off mixing a clear vrs laguna > they can be very inconsistant w/ their glazes and don't warn you when they've made a material substitute that can change the color or firing temp.

 

easiest way to control color- colored slips (colorent or mason stainsw/ bit of flux) under the glaze or as MS said >add color to thin downed glaze and experiment w/ amts.

 

For glaze coat > glaze consistency = vicousity of mcdonald milkshake should do it.

 

 

 

 

 

 

[Rex Johnson]

Milkshake was about right, one complete dip and a couple quick shakes to loose the excess glaze.

 

Yes, reduced are and closed the flue up a few notches til I got 4-6" flame coming out the peeps.

I think thre was more flame out the two top peeps than the bottom (uneven).

But I have those blower burners and not venturis.