I have to comment here that the difference in the firings is a lot more than just the cooling rate.
Heatwork. The one hour hold took that firing way over Cone 6 to at least 7 or 8.
Holding at six doesn't mean the firing just sits at Cone 6 .... Firing temps are a combination of time and temp.
Think of holding your perfectly roasted chicken in the oven for an hour longer at 350 ... Different result ... no matter how you cool it.
We really didn't need the basic lecture on heat-work. The essential message of this thread is the quality and quantity of iron, for this batch of Baileys Red, had more visible red effect than soaking and slow cooling with approximately the same heat-work for both firings. This may be exciting news for folks with older kilns who have been told "Slow cooling is an absolute must, or the only way to get iron reds."
No doubt you guys are on the right trail with the orifice size, but consider the frequent need for back-pressure mixing the particle settlement of glaze in the bottom of the supply can.
This is easily done by massaging the orifice with the thumb while squeezing the trigger. Hope the details didn't offend anyone.
I finished my first slow firing of SH glazes yesterday with results not even close. However, I'd be grateful to hear opinions on Baileys Red first. The firing schedule followed SH's for bisqued as supplied by Min on page one post two of this thread. The formula for Baileys also supplied by Min on page two post, #28 was followed using Spanish Red Iron. Only possible difference was synthetic Bone Ash was used instead of natural Bone Ash. I could not find any reference that advised either type for iron reds. The fast sample was fired in a neighbors kiln who used the Dawson sitter and no soaking or slow cooling. The photo shows the slow sample trying to go red on the edges where glaze was thin. There are also some speckles of red that appear to be crystals on the slow sample. Both were dipped in same batch, and the only idea I have is to try it thinner, but it is already not very thick. Thanks. John255
I've given up (for the time being) on Bailey's Red. Right now I'm getting good results with Juicy Fruit over SCM warm. I subbed Spanish RIO for the RIO in JF. Here is a pitcher (two views) that I unloaded this morning: http://ceramicartsda...wimage&img=2641
Jim, Beautiful result on your pitchers. Attached is what my Juicy Fruit looks like on SCM. On SH's DVD he emphasized that 60% of the glaze thickness on his pots is SCM. I followed that and sprayed it on rather thick. It flowed on all samples, but was quite dry to the touch. If Min is right about the Iron being weak that could be part of the failure. Thanks for your input. John255
The Magnetic Trimming Chuck can be a weekend project if you have a few hand tools and some experience cutting sheet metal. The 11.5" diameter steel disc is cut from galvanized sheet stock bought a Home Depot for $4. Although I didn't try it, you could probably get the same result using the bottom of a 11" two-part quiche (steel not aluminum) baking dish bought from a kitchen shop or Amazon, and forgo the cutting.
The steel disc is glued to any 12" bat that already fits your wheel. I stuck mine together with strong double sided sticky tape. Four 1/4" Neodymium magnets are countersunk and epoxied to three 1.75" square pine blocks. (See photos) Dimensions are not critical, but it is a bit of a trick to keep the magnets from jumping together during assembly. The blocks were faced with scrap foam Gripper Pad, but any medium stiff foam can be used.
So far the magnet trimming holder works well and is somewhat easier than using clay wads. I have yet to make up a set of extension dowel rods for holding tall pieces, but will get to it soon. This device is about 1/10 the cost of Giffin Grip and can be used on pots of any shape. Good luck and let us know how it goes, and if you have improvements. Please see edit below. John255
Hardest part of project is epoxying magnets, so I've added a magnet assembly jig. The photos show how to use it to make the three magnetic blocks. When chuck is finished first center your pot then slide the blocks to hold the pot. Not much pressure is needed.
Edit #2 To all members who are thinking of building a Magnetic Trimmer,
My attempts to build simple extensions for trimming tall pots were complicated.
Another approach I use successfully is to throw a double-ended trimming chuck and bisque
it then center it on the mag-trim. (See photo) Dimensions are not critical.
I use a bulls-eye level to level the pot in the chuck. (This assumes your wheel is level.)
You could also buy a set of extensions from Bailey for about $16 and screw then to the mag-trim blocks.