Sunday, November 17, 2013

Metallic Satiny Copper and Chartreuse Lime Green Glazes tested

This weekends results from the continuing tests of modifying and testing (and re-testing) ingredients and ratios to create both exciting color and silky smooth finish with a shimmer or sparkle:
This week I am looking for an apple to chartreuse green;   sorry my pics are washed out and don't quite show the amt of green they did achieve

One blend of barium glaze with the addition of rutile and copper, plus some titanium yeilded a more limey green when applied very very thin. But a bit too matte with a tendancy towards turquoise where thicker. Also the rutile lent some speckling (probably should have seived it better).  Interesting but not exciting.

Then I tested with chrome, adding high amounts of lithium in hopes of that sparkle, a good but not saturated enough yellow green color response, and a totally crazed finish and I mean badly.  (I am sure I am part to blame for removing it from the kiln just a bit early - however, I think this would have crazed even if I had waited)  Further tweaking to that test glaze with the additions of more barium,alumina, neph and a scosh of titanium.  This yielded a smoother less crazed finish, but lost some of the green and leaned more yellow.  My next modification of that will be to add some more chrome and a little more flint.  The one thing I found really exciting about this blend is near the top and bottom where I applied some RIO and Mng wash the line where the yellow green and the black meet turned a brilliant turquoise.

The thing that grabbed me the most was an unexpected shimmery smooth metallic burnt copper orange in a small area inthe well of the foot of a piece I had refired, where I had failed to wash away all of the glaze from the dunk.  Now if I can only figure out what created that!

Saturday, November 9, 2013

Glaze with a pearly sheen..... More testing ensues in my never ending search for "The Glaze"

I have been running a lot of tests tweaking and tweaking that barium glaze recipe for my little weed pots over the past week.  I veered off the purple variation for now looking for additional colors I could call my own.  Had a number of disappointments, but also some really promising ones.  My favorite tonite is a lovely mint green with yellow, which I will enhance with a bit more copper in the next batch to see if I can get a bit more of an apple green.   But I can't stop looking at it, it has a lot of promise!  Also born was an interesting deep mottled forest green and a super pretty medium blue purple too.  The light turquoise as well as the mint both have a lovely sheen, sadly the turquoise has to be applied so thin to retain the color that the throwing lines on the pot shows through and the texture is a bit too dry for my liking.  I guess burnishing them will help in that respect and maybe taking it up another cone.  I love the sheer veil and sheen in the turquoise, even with as hard as it is to get an even application,  so it will be worth the extra time to do that.  Take a peek at my results from todays kiln offering.


Friday, November 1, 2013

a study of crawl glaze pieces

Recently I mixed up a new barium glaze recipe that was noted as a lowfire cone 04 glaze.  Note, I used midrange porcelain for my testing bodies.
Interesting color response that I loved, but the feel was a very dry matte and the surface had a crawl effect (although it looks crazed it is not, the edges are smooth)  on the areas where thicker, the glaze turned a very vibrant purple and crawled, on the thin areas it was a lovely turquoise.   The color was brilliant though and I wanted to pursue perfecting the glaze to a smoother surface, in hope of keep the same color response.

I started by simply firing another piece to cone 5,  the glaze did not run, did smooth out a bit, but it still crawled in larger patches and  the brilliance in color was subdue.  The mottled look inherent of the nature of a matte finish.  Still I wanted this color, but in a silky soft finish. 
I mixed up another 1/2 batch (#2) this time increasing the flux via added neph and barium and continued firing at cone 5-6, no more low fires.   More neph seemed to make a deeper inky blue while more barium a lighter denser denim blue. 
Smoother, but where's the purple?  One more batch (#3) that I poured 1 cup of mixed epsom salt water solution into as part of my liquid, hoping the MgO would brighten the color up.  Well it did, but now we're back to a crawl effect.  Apparently all the mgo in the epsom salt water was overkill.  I will continue on, not making that mistake with the epsom salts and report new findings later on.  During these tests, I notice that on the pieces with a wash of red iron oxide at the base, a light green was occurring, so I also tested a few pieces that show the color response when iron is added.  I also had a green results over iron bearing clay bodies.

If anyone knows what ingredient will increase the purple, please feel free to leave a comment and I will play around with the amounts.
Ingredients in the glaze are Barium-Neph_EPK-Flint-Lithium-Copper
Happy Testing!