Very New to Firing - Cone 06 snapped during firing

[Elise]

Hello all, forgive my green abilities regarding firing. I have been throwing for about 7 years and just bought my first kiln. I got a brief run down from the previous owner on how to operate it but again, I’m very new to firing. I would appreciate anyone taking mercy on me by offering some tips :)

The kiln is a L&L Econokiln with a kiln sitter attached.

I ran my first firing last night. The previous owner told me to turn the 3 gauges on the kiln sitter on “high” and to crack the cover for the first hour if my pottery has any moisture. This is what I did.

On first look this morning, the pottery on the top shelf looks like it all fired completely (uniform lighter color and there appears to be some shrinkage) but is there something I can test make sure it did in fact fire all the way? I’d hate to apply glaze and have everything explode in the second firing.

One thing I did notice right away that I am pretty sure isn’t ideal is that the cone I used (Cone 06) snapped in half instead of bending. What caused this and how do I prevent in the future?

Also, the previous owner said to fire with a plug in the peep hole, is that accurate?

TIA!

 

 

 

 

 

[Benzine]

Welcome to the Forums!

In regards to getting rid of moisture, and making sure wares are dry, many potters will crack the lid, as you mentioned, but usually just run the bottom ring on low, not high.  This is known as "Candling" or "Water Smoking".  And this is usually over night, not just an hour.  One hour does not seem like enough time to drive out any remaining moisture. 

In regards, as to whether or not they fired correctly, yes, they should have probably changed color, at least a bit, and yes they should have shrunk a bit as well.  What kind of clay are you using, and what Cone are you firing to, for the final firing?

In regards to things exploding, that can only really happen, with the first firing, when there is still moisture in the clay.  If all the water, both physical/ atmospheric and chemical water is gone, the clay (ceramic) can't explode. 

That's odd that your cone snapped.  I've never heard of that, since things tend to bend and slump, when they melt, they don't snap.  Can you post a photo?  If it did indeed snap, you may have a bad batch of cones, or at least one that was. 

For the peeps, yes generally you should fire with them in, once you get past a certain point.  For a preheat/ candling, you can have one, or even a couple peeps out.  Once you get around 1000 F, I'd put them all in.  Also, you *can*remove them, if you'd like to speed up the cooling, but many times, it is just better to be patient and wait for the kiln to cool naturally.  

 

[Dick White]

Here is a link to a pdf from L&L about firing their manual kilns. http://hotkilns.com/sites/default/files/pdf/fire-manual.pdf

[liambesaw]

Keep your cones away from moisture, I had to toss half a box I left outside because they would snap in half half the time, and the atmospheric moisture from living in the great Pacific Northwest was the only thing I could think of that would have caused the rest of the box to fail.

[Mark C.]

(I ran my first firing last night. The previous owner told me to turn the 3 gauges on the kiln sitter on “high” and to crack the cover for the first hour if my pottery has any moisture. This is what I did._

I think some terminology is off here

Set the kiln sitter up with the right cone.Yopu can see this setup at Orton on U Tube

The sitter is either on or off-not high low or meduim-it holds the cone and shuts off the kiln

Turn your switches to LOW for a few hours-you can leave the plug out during this or in

then turn switches to meduim for a few hours then turn them to high to finish fire as siteerr will shut kiln off when cone melts.

Cones can break but it more rare -as noted in above posts did those cones get wet?

[Elise]

Thank you for this info! Some other terminology I messed up- I didnt use a “cone”, I used a pyrometric bar. The bar did in fact snap in half, I will post a picture of it when I get home. These bars came with the kiln so I’m not sure of their history. I will chuck them in case they are all faulty. 

It was a bisque firing to cone 06. 

The firing was not successful as the pieces are not completed fired- some broke in my hands and red clay wiped off red pieces with a wet sponge. 

So, I will re-fire these pieces, implementing the suggestions given here, and using the new cones that I have. 

[Mark C.]

The bars are more acurate than cones so just pick up a new box.Happy firing.

cone/bars last forever as long as they do not get wet.

[neilestrick]

Never go directly to 'high'. Do low for an hour, medium for an hour, then high. If things aren't completely dry when you load the kiln, turn the bottom ring on low overnight with the lid cracked. 

[Elise]

Am I correct to assume that the 3 gauges are in order of the rings they power? So, the bottom gauge would power the bottom ring of elements, and so on?

I refired last night, leaving the gauges on low for a few hours, then cranking to medium for another few hours then cranking to high. I used a cone from a new box I bought when I went to Georgie’s last fall. So these should be good. 

Everything looked good when I took a look this morning but everything was obviously still too hot to handle. I will inspect the pieces when I get home from work today.  The cone appeared to be folded over/bent in the correct formation (from pictures I’ve seen online) so I’m hoping it was successful!

Thanks for everyone’s help and advice! 

[Mark C.]

1 hour ago, Elise said:

Am I correct to assume that the 3 gauges are in order of the rings they power? So, the bottom gauge would power the bottom ring of elements, and so on?

YES

I refired last night, leaving the gauges on low for a few hours, then cranking to medium for another few hours then cranking to high. I used a cone from a new box I bought when I went to Georgie’s last fall. So these should be good. 

YES

Everything looked good when I took a look this morning but everything was obviously still too hot to handle. I will inspect the pieces when I get home from work today.  The cone appeared to be folded over/bent in the correct formation (from pictures I’ve seen online) so I’m hoping it was successful!

YEs

Thanks for everyone’s help and advice! 

More than welcome as our adviser fees are on a sliding scale to minus zero to zero depending on what one can afford

[Elise]

That’s a sliding scale I can contend with

 

I will be doing the accompanying glaze firing tonight, presuming that the bisque firing was successful. Any tips on glaze firing? I know to give the pieces at least 1/2” space between them and to use stilts/leave a little glaze free edge on the bottom of pieces. 

Anything other tips I should know?

Thanks again  

[Denice]

If your using the same glaze on all of your work you can get by with a half of inch,  some glazes are real bubblers so I would leave a inch.  Are the bottoms of your pieces completely glaze free and how far up the side is glaze free.   If you are using a runny type glaze I would clear at least a quarter of a inch.  If it is a real runner you need to put a clay cookie underneath it.     Denice

[neilestrick]

I generally leave less than 1/4" between pieces.

[Elise]

7 minutes ago, Denice said:

If your using the same glaze on all of your work you can get by with a half of inch,  some glazes are real bubblers so I would leave a inch.  Are the bottoms of your pieces completely glaze free and how far up the side is glaze free.   If you are using a runny type glaze I would clear at least a quarter of a inch.  If it is a real runner you need to put a clay cookie underneath it.     Denice

Hi Denice, thanks for your advice. I always leave the bottoms glaze free and usually leave about 1/8”-1/4” up the side glaze free in case of runs. 

What is a clay cookie? A stilt?

[Denice]

A clay cookie is a flat disc that you throw or pat out and then bisque fire,  you can make several sizes.  You put them under pots that  has a runny glaze to protect your shelves.   I was working with SCM glaze with different glazes applied on top of it.  The whole point was to get the runny glaze on look on it but sometimes it ran too much.     Denice

[Elise]

1 minute ago, Denice said:

A clay cookie is a flat disc that you throw or pat out and then bisque fire,  you can make several sizes.  You put them under pots that  has a runny glaze to protect your shelves.   I was working with SCM glaze with different glazes applied on top of it.  The whole point was to get the runny glaze on look on it but sometimes it ran too much.     Denice

Wouldn’t the piece fuse to the cookie if the glaze ran? Or do you use stilts also?

[Denice]

You put kiln wash on the surface of the cookie,  you would have some glaze edges to grind off your pot but it wouldn't be stuck to the cookie.  If the glaze ate into the kiln wash you can just throw the cookie away.    Denice

[Elise]

A side question- I got new shelves for this new (to me) kiln and I was advised to get some kiln wash, which I got. 

I believe the kiln wash says it’s cone 10?

What is the process of firing on kiln wash? I found directions on how to program kiln wash but I believe my kiln is a manual kiln so I can’t program anything lol 

 

edit- do I just need a cone 10 bar or cone and it’s the same firing process I used for the bisque firing?

[Min]

3 hours ago, Elise said:

I know to give the pieces at least 1/2” space between them and to use stilts/leave a little glaze free edge on the bottom of pieces. 

 

54 minutes ago, Elise said:

I always leave the bottoms glaze free and usually leave about 1/8”-1/4” up the side glaze free in case of runs. 

If there isn't  glaze on the bottom of the pots you don't need to use stilts.

If you can make your own kiln wash it would probably be better than using commercial wash. It's usually just 3 ingredients, alumina hydrate plus kaolin plus calcined kaolin (bisque fired kaolin), some recipes have silica in it. Either way apply it to the shelves, 3 thin coats are better than 1 thick one, let the shelves dry then just use them in your bisque fire. Don't fire the shelves when they are wet. You don't need to fire it to cone 10, that's just the rating the wash is good to for the stuff you bought.

[Elise]

Can I run the shelves with kiln wash on them in my next glaze firing or just with a bisque firing?

[neilestrick]

@Elise No need to pre-fire the kiln wash before firing pots. Wash them, let them dry, then load up the kiln.

[Min]

@Elise, couple more things just in case you don't already know this, but only put the wash on one side of the shelves and keep it back from the very edges of the shelves. If it's cracking when it's dry then it's too thick, sponge it off and start again. Wear a mask when mixing it up as you don't want to breath in the dust. If the floor of the kiln doesn't have an element in it then you can kiln wash the floor too, just keep the wash away from the elements.

[oldlady]

 

elise, if you have never fired before, you should know that most of us do not use the bottom of the kiln for placing pots.  put 3 half inch or 3 one inch posts under a shelf and use it as the bottom shelf.   that way, if you use a runny glaze it will only affect the very hard shelf and not the delicate soft brick of the bottom of the kiln.   can you post photos?  may we see  the L&L?  do you have whole shelves or half shelves?  you need only 3 posts per shelf if whole, 4 if half shelves.  

to keep your posts lined up as you stack shelves, put sharpie triangles at 3 equal points around the top of the wall of bricks so you put the posts in the same place each time.   watch out for the kiln sitter sticking out, do not put posts near it.   the sharpie marks will burn off so each firing will need new ones.   so much easier than trying to remember or feel with a finger where they are.

i have a newer L&L and i used to have an ancient one.  does yours have a manufacturing date on it?   you can call L&L to get more info using your model and serial number.

remember to have fun and enjoy the experience.  and keep a firing log.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Elise]

40 minutes ago, oldlady said:

 

elise, if you have never fired before, you should know that most of us do not use the bottom of the kiln for placing pots.  put 3 half inch or 3 one inch posts under a shelf and use it as the bottom shelf.   that way, if you use a runny glaze it will only affect the very hard shelf and not the delicate soft brick of the bottom of the kiln.   can you post photos?  may we see  the L&L?  do you have whole shelves or half shelves?  you need only 3 posts per shelf if whole, 4 if half shelves.  

to keep your posts lined up as you stack shelves, put sharpie triangles at 3 equal points around the top of the wall of bricks so you put the posts in the same place each time.   watch out for the kiln sitter sticking out, do not put posts near it.   the sharpie marks will burn off so each firing will need new ones.   so much easier than trying to remember or feel with a finger where they are.

i have a newer L&L and i used to have an ancient one.  does yours have a manufacturing date on it?   you can call L&L to get more info using your model and serial number.

remember to have fun and enjoy the experience.  and keep a firing log.

Hi oldlady  thanks for your advice. I had read that it was wise to put the bottom shelf on 1/2 - 1” posts for the reason you mentioned and also for heat circulation apparently. 

I am happy to share photos of my kiln, I just figured out how to resize photos so I can upload them here so I will take some pics and post here shortly.  I will also take a look for the manufacture date.

I have one full shelf that I use for the bottom and 8 half shelves. 

[Elise]

Here are the pics of the kiln. It’s model number says JX18