Firing Top and Sides, etc

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lbailey
Posts: 86
Joined: Fri Oct 26, 2012 2:53 pm
Location: FL Panhandle

Firing Top and Sides, etc

Post by lbailey »

So with help from Tony and others I have installed a switch that now allows me to fire 1) both top and side elements, 2) top only or 3) side only. (I can also manually adjust the heat from the top using a rheostat that Olympic installed on the kiln. This is obviously going to require documented testing to be useful, so for now let's just consider the 3 options with the top either fully on or off).

I have heard from various sources that there are advantages to using one of these firing options (instead of the other two) in certain scenarios. I have also heard that some folks actually change from one option to the other during a single schedule, i.e. top only for a slump, switching to side only on the way down to anneal.

Anyone have experience with this or can point me to a trusted source?

Thanks
Tony Smith
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Re: Firing Top and Sides, etc

Post by Tony Smith »

The first thing I would do with just a mold or shelf in the kiln, is to measure the max temperature with just the top elements and then just the side elements. Those will be the limiting cases for your testing going forward. I expect you won't get to slumping temperature with just the lid element, so now, you'll need to see how much side heat you'll need to get to slumping temperature. Make a table listing the element combinations along the side: top; mid-side; bottom side; top + mid-side; top + bottom side; mid-side + bottom side; top + mid-side + bottom side. Then across the top, list the numbers from the infinite switch: 2; 4; 6; 8; full. Or 1, 2, 3, 4.., depending on how many runs you want to do. You'll find that the lower infinite switch setting may be ineffective, so you can just go to a higher number. Also, you will always want to approach temperatures from below. Once heat is in the brick, it will be easier to hold temperature than it will take to get there with the same power setting.

Good luck.

Tony
The tightrope between being strange and being creative is too narrow to walk without occasionally landing on both sides..." Scott Berkun
DonMcClennen
Posts: 381
Joined: Sun Mar 09, 2003 9:09 pm
Location: Ontario

Re: Firing Top and Sides, etc

Post by DonMcClennen »

You will find that one solution/combination will not fit all the various types of firings! ... eg: full fuse, fuse to stick, slumping, bending, Drop outs..etc. Your going to have to adjust schedules for the results required, as I'm sure we all do. Only time and experience will give you the data you require.
"The Glassman"
jim simmons
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Re: Firing Top and Sides, etc

Post by jim simmons »

I have a kiln with elements on all 4 sides and the top.
I have made a schedule for most all types of firings and so don't have to switch any elements.
Just leave them all on and adjust the firing schedule for the type of firing that I want.
The other Jim
DonMcClennen
Posts: 381
Joined: Sun Mar 09, 2003 9:09 pm
Location: Ontario

Re: Firing Top and Sides, etc

Post by DonMcClennen »

I agree with, and have followed Jim's approach... for over 20 yrs. I think (Ibailey) you are complicating things by turning off and on selected elements for 99% of what we do in kilns.
"The Glassman"
lbailey
Posts: 86
Joined: Fri Oct 26, 2012 2:53 pm
Location: FL Panhandle

Re: Firing Top and Sides, etc

Post by lbailey »

Good to know Don, (I've been accused of that before..... :wink: )
seachange
Posts: 223
Joined: Tue Apr 18, 2006 1:19 am

Re: Firing Top and Sides, etc

Post by seachange »

Hi, my kiln has the same choices.

Have been learning to do drop vases lately. Found the best combination in my kiln is 50% power on the top (kiln ceiling) plus 50% low sides.

I like to test for best outcomes, so I did check all the other combos. It is very time consuming and takes a lot of glass :|

Best wishes, seachange
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