Larger kiln - schedule adjustments necessary?

[Eryc F.]

Hello! Now that I have my larger kiln (Jen-Ken 15/6), I was wondering...

An example:

If I use one shelf, with four smallish pieces on it, and I use a System 96 schedule...

OR I use two, or even three shelves, with 10 smallish pieces on each shelf, with each shelf seperated with one inch risers...

Do I use the same schedule? Do I have to slow down the ramp times to adjust for the extra "stuff" heating up and cooling down, or will the kiln adjust for it?

[Morganica]

Every kiln is different. You'll want to run some test firings to see how the new kiln fires. Probably it won't be that far off, but you've got new elements heating a different volume of air with a different controller/thermocouple, so you may need to make some small changes for single-shelf firings.

Stacked shelves in the same kiln? Usually not a great idea without a lot of experimentation, and even then it may not save that much time, because you'll be extending the schedule for overinsulated stuff in the middle and slowing down to avoid overcooking stuff on the edges. It's certainly doable for flat fuses, but it may take some time to get it right.

[haleybach]

Never mind
Misread the question and I can't add anything to what was said already.

[Eryc F.]

Thanks for the response! I'll do some experimenting!

[Richard Blummer]

Hi, Eryc,

I also have a JenKen 15/6, and I have never been successful doing multiple shelf loads in it at the same time, regardless of the my schedule rigging. The thermocouple is reading the temperature at the outer edge between the shelves, so the top shelf invariably overcooks while the outside of the undershelf is ok, and the middle of the undershelf undercooks. Glass kilns run by single-zone controllers simply don't have the "brains" necessary to pull this off.

Sorry, buddy. If you do manage to make it work for you, though, please post your method; I'd love to be able to use the JenKen for next years MagLess!

Richard

[Eryc F.]

Ha! Thanks Richard! I'm not going to doubt you. I may experiment if I have time, maybe in a few months.

I can't tell you how happy I am with this kiln! Bought it VERY LIGHTLY used for about half of what a new one costs from someone a half hour away that was moving to another state.

And going from a Evenheat Pro 8 manual controller to this... I'm pleased!!

Now I run both!

[Laurie Spray]

I do up to 6 shelves in one of my skutts. I always use at least 6" between shelves. That lets a lot of heat circulate and adds a tremendous amount of production. I do not, however, do large pieces this way as the edges will seal before all the air escapes in a bubble squeeze on sandwiched shelves. The largest I do stacked this way is 8 x 8". I do slow down my ramping but not that much.

[Eryc F.]

That's a great way of doing it Laurie. Unfortunately, the JenKen is only about 6" tall inside!

[Bert Weiss]

Heat up schedules change relative to different kilns. Heatwork is what you are looking for and it can be quite different from kiln to kiln. Take notes to remember how to get the job done in each kiln. The good news is that annealing schedules, for the most part, are the same. The one factor that can effect annealing schedules is uneven temperature in places inside the kiln. If you spend too much time in an uneven environment, you can introduce that difference in to the glass and this could make annealing impossible. One place to look for this happening is close to the kiln walls.