Looking for help on kiln repair

[lilclaylady]

Hi, 

Thank you for reading! I am desperate to get my kiln working, I have been working on it for 6 months now. My husband has helped me replace the elements, it worked for 2-3 firings then wouldn't reach cone 5 but would bisc fire fire. We replaced the switches and the electoral tabs at the ends of the wires where they meet the switches & coils. It is still only firing to cone 3/4.

The kiln sitter was replaced about 9 yrs ago and has probably done about 100 firings.... I don't think there is anything else to replace.  Do you think its the kiln sitter? It has been calibrated correctly too. 

My only other thought is if my husband could have made  a mix up when installing the infinity switches. He is wondering if we should install the other kind of switch with only low/med/high spots, even though this is not how this kiln was built.

It is a cress b23 h.... Very Very old maybe 30 yrs old? Is putting any more time/ money into this a lost cause? 

 

Thank you for your thoughts and help. 

[Hulk]

Hi LilClayLady!

Is that kiln max temp rating cone 6?
Here's the documentation I found:
Item # B23HT-240 On Cress Mfg. Co.

If so, it might be more serviceable for low fire. Likely it will struggle to reach cone 5 once new elements have started to wear/degrade.
Likely it wouldn't take many firings to lower the actual max.

As for being worthwhile, the condition of the unit* and how it matches up with your expectations could matter more than its age.

*bricks, casing, wiring, stand, everything, including the control mechanism.
My kiln is over thirty years old, it's a cone 10 though, so suitable for cone 5/6 work. Its bricks and lid are going, so I'll likely upgrade when the elements wear out. It might take another fifty firings to wear'm out. The seller included a full set of posts, brand new shelves, boxes of cones, and some glaze materials - so far, it's been a fair deal.

[Bill Kielb]

6 hours ago, lilclaylady said:

It is a cress b23 h.... Very Very old maybe 30 yrs old? Is putting any more time/ money into this a lost cause? 

If it’s truly a cone 6 max kiln it really will not reach cone 6 unless the elements are fairly new and all connections are spot on in very good order. At 6000 watts ( if this is yours).it is more suitable as a lowfire kiln.  Cone 10 rated kilns usually provide 100-150 firings when used for cone 6 work because kilns are designed with only about 110% capacity new. If  the elements have worn by about 10% they generally struggle to reach top temperature. If your element resistance has risen by that much compared to brand new then likely they are just worn too much. So easy enough to measure and determine if this is the issue. Most folks recommend cone 6 kilns be used for lowfire work only for this reason.

Edited July 28, 2022 by Bill Kielb

[JohnnyK]

I had the same situation with a Cress B-23-H...mine was given to me by an 87 year old ceramist who wanted to get rid of it since it was a spare that she did not need anymore. I tried firing it to ^5 but found that it did not work for that. Fortunately, I came across another potter who was selling her ^10 with 3 shelves, furniture, and 300 pounds of dried out clay for $500. I bought a digital timer for the newer kiln and since it would only heat to ^2, sold the old kiln as a low-fire kiln for $200 to a restaurant owner who wanted to make his own unique dinnerware. 

If you're looking to do the ^5-6  thing, I would recommend upgrading to an appropriate kiln...new or used (if you can find one).

[Callie Beller Diesel]

17 hours ago, Bill Kielb said:

Cone 10 rated kilns usually provide 100-150 firings when used for cone 6 work

I do wonder about the Cress kilns on this. I have a cone 10 model that was made in the 80’s. One of those found second hand kilns that had been used 3 times by the original owner and stored ever since situations. I’m well over the 100 firing mark, and my elements are still going hard. I even bought all the backup parts to have on hand, but I haven’t needed to use them yet. 

[Bill Kielb]

36 minutes ago, Callie Beller Diesel said:

I’m well over the 100 firing mark, and my elements are still going hard

Must be a cone ten kiln I assume. 200 firings (cone 6) would be a bunch if you can make it. How many watts for the size and how well insulated it is are the main variables that limit most kilns.