Wednesday, September 30, 2009

Line test of SCM with yellow iron oxide



The results of a line test of strontium crystal magic with yellow iron oxide 3-12%. The results were meh. Shades of brown and tan. I get much better results with an iron red over SCM. Though I think I will mix a batch of this with 5% YIO and use it under an iron red.

Saturday, September 26, 2009

New lorio ash recipe

As promised the new version of lorio ash. Samples pictured in prior post.

Alberta Slip 43.5
EPK 5.9
Whiting 29.6
Wood Ash 13.9
Grestely Borate 8
RIO 3
TiO2 6

Reworking a glaze for testing

So I have a version of strontium crystal magic I had some decent success with and want to line test it with yellow iron oxide to see if I can coax a good orange out of it.

First thing I want to do is normalize the recipe to 100 grams. This is done by getting the total weight of the ingredients ... I'll call that W then dividing each ingredient by W. I'll call each ingredient's weight x. The result of this equation is the normalize weight I am after, I'll call that number... R. The equation is pretty simple:


R = x/W

Keeping in mind that R will be a decimal, less than one. It can best be thought of as a percentage. I set up a simple spreadsheet template to handle this for me.

Here is my initial recipe:

Strontium Crystal Magic

Custer spar 120

Whiting 45

Strontium Carb (type D) 33

EPK 39

Fr 3124 12

Lithium Carb. 12

Titanium dioxide 36

Bentonite 6

Yellow Iron ox 6 for orange


Now I did one other thing to get this recipe ready for line testing. I pulled the yellow iron oxide out of the recipe. I did this because I want the main recipe, the recipe without colorants to equal 100. I can add colorants later. Here are the R values I get for this recipe:



Custer spar 40
Whiting 15
Strontium Carb 11
EPK 13
3124 4
LiCarb 4
TiO2 12
Bentonite 2

Add it up and you get 100. Which is much easier to work with when testing a glaze. Now because I pulled the yellow iron oxide out and it was initially 6 I know that it was initially about 2%. So I am going to start my line test at 3% and go to 13%.

For line tests I use 100 gram batches mixed up in the plastic beer cups you get when you go to a party. I'll mix up 10 identical batches of dry ingredients then drop in the correct amount of colorants, add water, drip or brush my tiles (spraying them is a hassle) and wait for the next firing to see the results.


Friday, September 25, 2009

The new version of Lorio ash

A couple pictures of a vase with the new version of Lorio ash I made. I really like how it turned out. Again the glaze doesn't run past where it was applied.

The recipe is at the studio on a piece of paper. I will post it when I bring it home.


Rule Number 1 of Glaze Club


I have some new glaze test results.

I tried a new version of strontium crystal magic that I got from a cone six glaze group.

Strontium Crystal Magic
Custer spar 120
Whiting 45
Strontium Carb (type D) 33EPK 39
Fr 3124 12
Lithium Carb. 12
Titanium dioxide 36
Bentonite 6
Yellow Iron ox 6 for orange

I was very excited to get this recipe. I have a working version of SCM but I couldn't
for the life of me get the signature orange color of Steven Hill's SCM. So here is this group that Steven Hill is involved with and I have high hopes for this glaze. Here's
the result:


The result is promising but not exactly what I was looking for. I forgot the first rule of glazing... glazes don't travel. To give you an example of why glaze tweaking is so important and how badly some glazes travel I give you my own story. We have three electric kilns in the studio I use. I have one glaze that looks different depending on which of the three kilns you fire it in. One kiln is beautiful, one I get teadust crystals - this is not a teadust glaze, the third never fires it to maturity. So I was foolish to rush out thinking that someone else's version of SCM would magically work for me. Developing a glaze is a very personal and individual quest.

The reason I got a pale peach color instead of the vibrant orange could be any one or a combination of several factors. As always someone else's gaze recipe should never be anything more than a starting point.

So the next thing for me is to start pulling the levers to adjust this glaze to produce the color I want in the kilns I have. One thing to note is that I will only adjust one factor at a time. If you change more than one item at a time you will have trouble determining what worked and what didn't. The first thing I will tweak is the amount of yellow iron oxide. I am going to do a line test - 3% - 13%. I expect to get the color I want somewhere in that range.

I have 3 other new glazes but I am late starting dinner I will post those later.

Thursday, September 17, 2009

Pitchers

I have been pretty busy looking for a new house and haven't spent much time in the studio.

I did get a chance to make some pitchers. I have 3 drying. Not a lot but I don't do pitchers very often.

I am hoping to get some of the bisque ware I've accumulated glazed this weekend. Try out that new version of lorio ash.

Thursday, September 3, 2009

Test results

Opened the kiln this morning.

I had two test glazes in the kiln, a very modified lorio ash and a modified Leach Yellow Seto.

The modified lorio ash came out exactly how I expected and what I wanted. Yellow with darker rivulets. As importantly to me the glaze ran but not too much. The amount of run I am looking for is a pronounced but controlled run. Sound confusing? Not really, my criteria is simple; No running past the application point. So on a vertical test tile the glaze runs no further down the tile than the brush/dip line. This glaze didn't. The runs stopped right at the brush line. I am extremely happy with this test. Now the next step, putting on pots.

The yellow seto came out strange. Very matte. I suspect it didn't melt. But the thing is... it came out purple. Yeah, freaking purple. A dry matte purple. While certainly not what I was after it's interesting nonetheless. I am debating next steps here. Not sure if I fork the recipe keeping a small batch of the recipe as is or just bagging it and working on the recipe to get the result I was after.

Lastly my very dark blue glaze - I had three pots glazed with this glaze, all three developed tea dust like crystals. Not what I expected. Not sure if this was an application issue (too thick) or the kiln under fired. I didn't load or fire this load so there were no witness cones, normally I always use witness cones. Without the witness cones I can't say for sure what cone the kiln fired to.

Wednesday, September 2, 2009

Back at it

So the house thing fell through. The house had dry rot, insects, and a bad foundation. We're looking again but in the mean time.... back to the studio!

I pulled a couple tumblers out of the kiln that came out very nice. I used an iron bearing stoneware to make these. I normally use porcelain but once in awhile I like to switch it up and use an iron bearing clay just to keep things interesting.

Well, these tumblers had clear liner inside, the outside had a thin coat of strontium crystal magic (mod), then a coat of an iron red, then some highlight stripes, grestley borate/rutile and a copper saturated nuka. The combinations worked really well.

One of the glazes I am missing from my palette is a reliable yellow. To that end I mixed up a modified version of Leach Yellow Seto today:

Wood ash 48
Yellow Ochre 25
Neph Syn 25
Lithium Carb 2

We'll see if it A. Melts B. Doesn't suck.

Oh and in the same kiln load I am firing a test of the modified lorio ash I mentioned a couple posts ago. I replaced the rutile with RIO and TiO2 and bumped up the flux to increase the run and smooth out the bubbles.