Glaze tests

[Randy McCall]

There are a number of glaze tests on my web site in the Potters Corner if anyone is interested.  Many tiles are layered glazes some of which are commerical glazes I have tested plus many others.  Pictures are included.

 

Make sure you scroll down past advertizements at top of page.

[eleanor akowitz]

Randy - i checked your photos and saw several mentions of the grren matt and the blue matt. are these commercial glazes? if not, i would like to see the formula for both these glazes. they are very interesting especially when layered.
hopeing to try them on porcelain ^6
eleanor

[Randy McCall]

The green matt and blue matt are from Jane Shatz. I do not have access to my glaze formulas right now but will get back to you tomorrow. Those glazes work great under and over nutmeg especially if you do a hold at 1650 F for one hour.

[eleanor akowitz]

thanks in advance. i look forward to getting and testing them. i am running a kiln tomorrow and will include them if i have the chance. i do a slow cool from ^6 to 1900 then drop to 1400 with another slow cool. i will try it on my schedule to see how it works and then will probably try again with your ide of cooling.

[Randy McCall]

From what I have gleaned from ClayArt with the iron reds the most important temp to HOLD is around 1650 F. I just do an hour HOLD after reach top temp at that (1650)temperature. I usually fire for 15 more minutes after my kiln sitter drops to make sure I get a hard Cone 6. That seems to work with the glazes I have been using. I was getting alot of pinholes in some of my glazes but started putting my med temp on both bisque and glaze firing to 5 hours. This cured my pinholing in my semi transparent glazes.

[Randy McCall]

Eleanor

Here is the green matt. I derived this glaze from Jane Shatz Blue Matt. I used this glaze extensively under and over nutmeg. It works best using it thin over and under thin nutmeg. One coat of each. Consistency of milk.

Recipe Name: GREEN MATT

Cone: 6 Color: blue
Firing: Oxidation Surface: Matte

Amount Ingredient
7.2 Dolomite
11.3 Gerstley Borate--1999
13.9 Talc
39.1 Nepheline Syenite
9.5 Kaolin--EPK
19 Silica

100 Total

Additives
4 Copper Carbonate
6 Rutile

[Randy McCall]

Green Matt over Nutmeg next picture is Nutmeg over Green Matt

The nutmeg over green matt usually turns out a nice smooth celadon green as long as both glazes are applied thin.

[Jeff Poulter]

Hi Randy,
I went to your site & the one combo that got me going was the Baileys Red/Orange w/C. Shino & C.Red Gold over it. I didn't have time to make up a test batch of Baileys, so I took a tile & put Ketchup,Brick Red,Ron's Red, Red Wood, Flame & Pete's Tomato Red as the base. I had 3 different Coyote Shinos, Regular, Light Blue & Leopard. They went next. Then to top it off, I put Red Gold & JB's Brown. Talk about good combos! My only regret is that the test tile was white/buff clay instead of a red clay, so I think they will look even better on a red clay. Now I just have to throw something to put it on. Everything that I have sitting there bisqued is ^10. Anyway I am glad you did those tests as I would have never thought to do a combo like that. I had forgotten that I even had those Coyote glazes in the basement. This was a fast up & fast down. I wonder what a slow cool with a hold at 1650 would do? jhp

[Randy McCall]

Jeff

I have never been disappointed by doing a hold at 1650 F. Everything seems to turn out great. I have discovered that layering is the only way to go at Cone 6. You can get some wonderful effects. Layer everything you have and it will be like Christmas time at every kiln opening.

Take pictures and show us your results. Share, share, share.............

[Jeff Poulter]

So here is a test tile that I did after viewing Randy's site:

The vertical stripes from left to right are:
1-Ketchup
2-Brick Red
3-Ron's Red
4-Red Wood
5- Flame
6- Pete's Tomato Red #13(spangly version)
The 3 horizontal sections from top to bottom are:
1-Light Blue Shino
2-Shino
3-Leopard Shino
The upper stripe of each section is Red Gold & the bottom stripe is JB's Brown.
This was a fast fire to ^5 with a 20 min. hold, which gives me ^6 touching down.
This next pic is the same tile re-fired to 1220 C., quick cooled to 1100 C., then slow cooled(50 C./hr.) to 900 C. with a 60 min. hold @ 900 C. & then off.

jhp

[Tracy Shea]

I'm with Randy on the hold at 1650 for an hour.
This is a red glaze I use, almost identical to "Randy's Red"- got it years
ago in school.


flint-26
epk-4
RIO-18
Gerstley Borate-28 (I still have a stash, haven't subbed yet.)
F4 spar-18
talc-12

M^6 "Waterfall Brown" will also turn red if you fire this way.

[Teresa Wooden]

I just experienced an unusual reaction with Coyote Cedar Shino, which I've been testing recently. Fired some to cone six. Peeked in the kiln at 350 F (yes, I know...but hey, I've seen Steven Hill pull his out of the kiln at 400...) I was sad to see that the Cedar Shino was dark brown, very overfired/burnt looking. Well, bummer. So I pulled that one piece out and sat it on the table to get a good look and feel sorry for myself. Went about my business glazing other pieces.
In about half an hour I glanced over and low and behold, the piece had turned from ugly dark brown to a lovely deep red, just sitting right there on the table! I've never seen a glaze react to room temp cooling like that before. It was neat.
So far in my testing this glaze has performed well and has had no problems with pinholing, crazing, etc. I probably wouldn't put it on a food surface, as it has encapsulated cadmium (at least not without having it tested on your claybody). Nor would I use it in combination with another liner glaze without stress testing it for COE compatibility.

[1486rcsfei9hn]

We use a lot of coyote glazes and they do change colors as they cool.  We have had very good and consistent results.