Is the top collar on old Gare 2327 kiln necessary to reach c6?

[mikeblake]

I have an old Gare kiln. I fired it for the first time doing a bisque fire, which was successful.   However, the glaze fire would not rise above 2050 for a couple hours (it was actually climbing but only 3-5 degrees an hour) so I shut it down. I was firing c6 glazed wares.

This kiln has an upper collar which I did not use because I had enough to fill up the bottom part, and I’m wondering now if it needs those upper elements to reach c6.  Does anyone know if this might be the case?  The elements are old but seem to all be glowing during my initial tests.

 I’m assuming that even if things look good tomorrow morning when it is cooled down, that any dinnerware would be deemed unsafe to use having not been brought up to c6. 
 

Thanks for any info or help anyone can offer.  Feeling a little disappointed with my first real home studio firing.

[neilestrick]

Is the extra ring a normal part of the kiln that you took off, or is it an add-on to make a certain model bigger? How is the extra ring connected to the mail box? Post a pic of the serial plate.

Kiln elements are made to work with the known heat loss from the bricks. If you have a kiln that's 3 rings tall, you've got a certain amount of the interior surface area producing heat (the walls with the elements), and a certain area that is just losing heat (floor and lid). The elements are made to produce enough heat for that ratio. If you remove a ring, you've changed the ratio of heated area to unheated area, and the elements may not work with that ratio. However, if you've got a kiln that was made to work with 2 rings and you add a ring, then it won't matter.

Do you have a meter to measure the element resistance? It may be that they're worn out.

[Chilly]

14 hours ago, mikeblake said:

dinnerware would be deemed unsafe to use having not been brought up to c6

Did you use witness cones?

2,050F for a couple of hours might have reached ^6.

[Bill Kielb]

15 hours ago, mikeblake said:

if it needs those upper elements to reach c6.  Does anyone know if this might be the case?  The elements are old but seem to all be glowing during my initial tests.

It very likely will help and may be nearly necessary to have those upper elements especially with worn elements. In its most basic form you will have more element to offset the load in the kiln which will appear as a lightly loaded kiln and a light load on the elements. Empty kilns fire much easier than densely loaded just for this reason.

 As far as losses, the elements have to offset the loss through the walls, lid, and floor therefore double the available power to offset the lid and floor.

Less element loading, so logically it should fire much better with both sections powered. Checking the elements with an ohm meter will tell the story on the element life. If their resistance has gone up by 10% or more, time to replace.

[mikeblake]

Thanks for the replies. I did use witness cones 5,6,7 in three places and the 5 and 6 didn’t even start to bend. They all changed color to white though. 
 

The upper ring is a part of the kiln and plugs into the main box.  
 

I’ll have to do a test I guess with the collar to see if it will get up higher. A friend of mine told me I should fill the kiln with shelves and posts so it’s not completely empty, does that sound right? 
 

I don’t have an ohm meter but will prob pick one up if it’ll be a useful part of monitoring and maintaining the kiln.

I’ve attached a picture of the serial plate. The electrician I had install the kiln was supposedly took the specs into account when he ran the line and connected it. 

 

 

[Bill Kielb]

38 minutes ago, mikeblake said:

A friend of mine told me I should fill the kiln with shelves and posts so it’s not completely empty, does that sound right?

If you want to simulate a loaded kiln, load it with something of similar weight. The density (basically weight) of the load will determine how much energy is required.

from above::

On 12/21/2021 at 12:47 PM, Bill Kielb said:

In its most basic form you will have more element to offset the load in the kiln which will appear as a lightly loaded kiln and a light load on the elements. Empty kilns fire much easier than densely loaded just for this reason.

Firing an empty kiln is much easier, so to simulate a full kiln, fill it.

BTW, I suggest get the meter, it has many uses and guessing at some point is just a waste of time.

[neilestrick]

6 hours ago, mikeblake said:

The electrician I had install the kiln was supposedly took the specs into account when he ran the line and connected it. 

Did the electrician install a 60 amp breaker? Kilns must be on a breaker that is 25% greater than the draw of the kiln, so your kiln should be on a 60 amp breaker to be up to code.

It probably needs the collar. With each section pulling 15 amps, the two sections are under-powered. Most new kilns that are 23 wide by 18 tall pull close to 40 amps, 30% more than your kiln with two sections.