Third Friday: Cone 6 Glazes - Firing Methods

By Marsha Neal Studio

Welcome to the Third Friday Cone 6 Commercial Glaze Test Post. This month, instead of focusing on some glaze test results, I thought it might be a good time to talk a bit about how I work around the sagging rod issue with a lot of commercially available bead trees and high temperature wire when firing to Cone 5/6.

There is a lot of information out there on the internet and in previous posts here on the BOC Blog, including one on High Temperature Wire last week, and the BOC Yahoo group, so I'm not going to take the time to reinvent the wheel and research all the various links and details. Just the basics and some general photos on how I suspend my pieces on hooks and rods in order to get an entirely glazed piece and avoid sagging points and overall have a successful glaze firing all the way up to cone 6.

Decal, Cone 2 firing, but still loaded as if firing to Cone 6.

One thing that I learned - the hard way - with bent rods, fused pieces, glaze drips puddled and fusing bead trees to shelves - is that every kiln firing is different.

Pendants that wanted to kiss permanently… awww (not!)

Get to know the "weight" of your pieces and place them as evenly as possible along the rod on the bead tree. If you have a weightier piece, place that closer to one of the actual bead tree supports, not at the end or the middle of the rod, because the weight will cause the rod to sag when it heats up. It is better to be overly cautious then to be fast and not pay attention to details. You've put a lot of work into your piece to this point, don't let it slide now (literally)!

Here is a bunch of pics of my small test kiln. Knowing the inside dimensions of your kiln & max firing temperature are two important things before you purchase your kiln. Nothing like spending money on something that won't work easily for you…

Notice the nice patina on the bead trees from years and years of firing? Also, the kiln shelf does in fact have kiln wash on it. You can see the white when I removed the furniture. I don't bother to re-coat this one shelf. Also, notice that the last picture has two different bead trees in it? The kiln won't shut with the taller one, so that one does not get used as much.

Here is the small kiln after a glaze firing. See how keeping similar weighted beads evenly spaced (and hanging them from wire hooks) allows the rod to sag minimally? A quick note too - I've altered these bead trees to fit an additional row up top by adding up-side-down U-shaped wire stoppers to keep the rod from rolling off the top of the tree. I have contacted the mfgr of the bead trees to see if they would make me some with different "holes" but they will only make them with a certain number minimum order. If you might be interested in any, let me know by email and I will contact them with the design if we have enough interest.

You can also fit more in if you plan how you are going to load the kiln:

The above picture shows you how I sort my pieces out to shape and size before going into the kiln room to load them. This allows me to easily pick out the correct size wire hook (by gauge wire and length of hook) for the piece.

Now by wire hook, I mean a hook that I make with the Kemper High Temperature Wire (Nichrome). I also have some different versions of Kanthal wire to test out (bottom center picture) but that will be another post. I pre-make and then pre-fire these wire hooks using old jewelry making pliers that I don't intend to re-use for actual jewelry making. This allows me to be as rough as I want, whenever I need, without having to dig into jewelry making supplies. I keep the wire hooks in smaller containers separated by gauge. My tiny pendants get the small gauge wire, the larger ones get the larger gauge wire. Pretty simple right? Experiment and see what works for you.

Remember, the wire (hooks) won't last forever when you fire it over and over again. Eventually it will become brittle and break. The rods, well, they just get a nasty green coating from the oxidation of the metal. You could wipe it off, but it will just keep coming back. I read something more about that process somewhere recently and will have to look into it again.

Here is a loading technique that I think a lot of people use. Kiln post furniture with wire supports. Usually topped with another kiln post to keep the wire from sagging or moving.

This kind of firing works well too - but for my obsessive self - it drives me nuts to load a kiln that looks like this:

Here, I've got to end with this one to please my eyes:

…Even better upon opening :) But I never seem to remember my camera at that point because I am too excited to get it all out.

Comment away - questions, concerns, etc. I'll try to get back to you as fast as I can.

E