Jump to content
Sign in to follow this  
ronfire

Over Fired

Recommended Posts

Well I got distracted and forgot about the kiln and of course as luck would have it the cone sitter did not shut off at cone 6 for the glaze fire. Usually the high setting runs for about 2 ¾ hrs, I shut it off  after 3 ½ hrs. I was probably 45 min too long and all the cones are melted out of site including the cone 7. Not sure what I will find, have 24 pieces in there . The glaze is cone 6 and the clay is cone 2-7. 

Share this post


Link to post
Share on other sites

Yes the clay is a Plainsman M340. I took a peek on the top shelf and it looks to be ok. I have not unloaded it yet as it is still pretty warm but I think I will be ok. Will post again after I unload the kiln.

Share this post


Link to post
Share on other sites

Well all the pieces came out fine except 2. 1 had a couple of chips on the bottom  and 1 thin plate warped. Don't know how hot it got as all my cones 5-7 where flat.

I think the problem was that I did not put more kiln wash on the Sitter parts.  Now I set timers to remind me to look at the kiln.

Share this post


Link to post
Share on other sites

I did notice that the cone had stuck on the sitter rod and shelf this time instead of being lose, might have been from the higher temp.  

I will check again with the setting gauge and see if anything has moved, can't see why it would change unless thing warped with the heat.

I have some old sitter bars that came with the kiln I might try them instead of the cones and see if I like them better.I know that would not solve the problem but might be a little more consistent . The problem is my supplier does not carry sitter cones. I always set the cones up the same way and is the # stamp as a guide to place the cone but still find there is small changes to the witness cones between firings .

Share this post


Link to post
Share on other sites

 The problem is my supplier does not carry sitter cones. I always set the cones up the same way and is the # stamp as a guide to place the cone but still find there is small changes to the witness cones between firings .

 

I can pick them up for you and put them in the mail if it helps, I'm in BC too. PM me what cones you need and your mailing address if you want some.

(prices from where I buy mine are Small cones (box of 50).....$10.90 Small cones, each.................$0.44)

Share this post


Link to post
Share on other sites

In 23 years I've never used wash on the sitter parts, either, and never had a problem.

 

One thing that can happen is that over time the sitter rod gets worn out. It either degrades and gets thinner, and/or it warps, both of which can cause it to malfunction. So take a good look at the sitter rod and make sure it's not bent or thinning.

 

If the cone melted a bit and stuck on the support bars, take them out and file or grind (carefully) them clean, or replace them, before firing again.

Share this post


Link to post
Share on other sites

I rebuilt the kiln with new sitter rod and supports about 15 firings ago, guess the rod could now be out of adjustment from the heat. I will check it out before the next time.

Any chance you can elaborate on this adjustment and tools used? I have just purchased new parts for my sitter and it did not come with any form of adjustment instructions. I needed to replace my ceramic tube & rod as the tube itself was completely gone (old kiln we have had for 15 years and was used before we had it). Now that we have got time on our hands, my wife and I have picked up where we left off and the equipment is getting used more, these little details about servicing equipment need  to be relearned.  

Share this post


Link to post
Share on other sites

The manual for the kiln sitter is here: http://skutt.com/images/5780/Dawson-LT-3-and-LT-3K-Manual.pdfwith complete instructions for adjustment a few pages in. A new calibration disk can be purchased from most of the usual online suspects or maybe your local supplier has them in inventory. They aren't expensive. The hardest part of the adjustment is getting the 1/16" clearance between the claw and the drop plate. I've found that can be done quickly using a standard 1/16" twist drill bit as a thickness gauge. Loosen the drop plate screw and move the drop plate up behind the claw so it doesn't fall free. Now adjust the claw in or out as needed until the drill bit just slips in between the drop plate and the claw. Tighten it in place and readjust the drop plate downward until it just barely clears the claw. Tighten it, and you are done.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use.