Wednesday, November 14, 2012

Ooooops! Meltdown!

Well - it happens to everyone eventually. Either the kiln, or the operator, fails and ooops - the temperature goes too high and you ruin a kiln full of beads.

So it was inevitable that it happened to me at some point. And it just did.

I was just heading past the kiln, and I looked at the temperature as I went by, and instead of a temperature, it read:  "HTdE."

Hmmm. That's not normal.

Cracked open the kiln door - woo boy  - it's glowin' like Chernobyl in there. The beads have actually dripped off the mandrels, and melted into a big free form plate (proving that glass really does want to be 1/4 inch thick).

Not good. 

Ok, turn kiln off. Look again. The glass has flowed all over the floor of the kiln and the mandrel rests. The beads are one big puddle.

Nothing here is salvageable - let's try and mitigate the damage to my kiln.

Pull the mandrels out and put them aside - on something non-flamable, please!

The glass however - that's a lot of heat. Fill a bucket with water.

Pull the kiln rests out with the long tweezers, and take outside and dump into the bucket.

Inside the kiln, a few "cabochons" of glass remain - but some poking with the tweezers frees them from the floor of the kiln. Never did get around to putting on that recommended layer of kiln wash that all the books say you should put on the kiln floor for just such an emergency. Fortunately - the kiln floor was fairly dirty - which made it easier to get the glass off.

Here's some pictures so you can see the gory details.

These are the mandrels - sans beads.  :-(

My glass encrusted mandrel rests. Notice how nicely it goes with the autumn leaves?

 Pulling it out of the bucket.  A metal bucket would have been better, but I was in something of a hurry at that point.

See - it pays to not sweep out the floor of your kiln. You can see the accumulated flaked off bead release on the bottom of the glass. Once again, being lazy saves the day!

The error message, HTdE, btw - is High Temperature Deviation - meaning the kiln overshot it's target temperature by more than 100 degress. Possibly due to a stuck relay. I will be watching the kiln like a hawk for the next little while.

Or possibly because I accidentally turned the kiln off, restarted the program, and didn't give it time to establish what temperature it was at before telling it to Skip Step. Seems to me I saw this happen before - it just didn't matter because there was nothing in the kiln at the time.

So - give it a few minutes if you have to restart the program on the kiln, and never forget to check the temp occasionally - just in case.


  1. Oh sorry this happened! Will certainly take your warning to heart and check the temp if I have to turn off and start agin. At least there was no permanent kiln damage.

  2. I have a couple of fusing shelves that are now glass coated - operator error
    got distracted - hope yours is a simple repair

  3. Gail DB2:04 p.m.

    Ouch! Sorry to hear about your disaster, but glad the kiln was salvaged.... now get out that kiln wash. :-)

  4. Thanks for posting all the details and the pictures of this. I've wondered what would happen if the relays ever failed and the kiln got too hot.

  5. I just had this happen to me too!! It was totally operator error, I thought I had put the kiln into a fire polishing program and it was on a full fuse instead! Can you say puddles? Luckily, I had them sitting on a kiln washed shelf, nothing damaged but my pride! Jeri