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hello I have just purchased a second hand cromartie hobbytech 40 kiln with an lt3k kiln sitter,  having never fired my own work (I have always had a technician do it) I was wondering about the ramping speed to fire stoneware.            The kiln has a dial on the side from 1 to 4 and then full, I was wondering how long I should leave between each increase in power. as I understand it too quick an increase in temperature could cause the clay to break due to the steam. 

here is a picture of the kiln dial.

also the Kiln has a peep hole in the side and a vent hole on top, should I leave both open during firing?

regards

Liam

 

kiln dial.jpg

Edited by hennesli

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For bisque, if things are not totally dry, keep the peeps open and put it on the lowest setting overnight. Otherwise just put it on the lowest for an hour, 2 1/2 for an hour, then Full until the cone drops. If you have large or thick pieces, double the time on each setting. If you do not have a downdraft vent attached, keep the top peep open during the entire firing.

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I too have just acquired a secondhand Hobbytech 40 with LT-3K Kiln sitter. How did you get on with yours firing?

I've used a large Northern Kilns kiln previously, with Stafford electronic controller, so the idea of firing at home is quite daunting. I am reading up everything I can online about the Hobbytech 40.

Does anyone have a link to the user manual? I've tried Google for this but to no avail.

 

Thanks

Rob

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I have the exact same kiln. I start with the kiln on 1 for 3 hours ramp it up to 3 for another 3 hours then put it on full until the kiln sitter kicks in. For 06 bisque firing it takes around 7 -9 hours (exterior temp dependent) and for cone 7 it takes about 10 -12 hours. I leave the peep hole and vent open in both firings until there is no steam coming from the peep hole, use a mirror to check this. Then I plug the holes and leave them in until I open the kiln about 20 hours after it has switched off. My biggest issue is getting a supply of of mini bars to operate the sitter.

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9 hours ago, annacondagh said:

I have the exact same kiln. I start with the kiln on 1 for 3 hours ramp it up to 3 for another 3 hours then put it on full until the kiln sitter kicks in. For 06 bisque firing it takes around 7 -9 hours (exterior temp dependent) and for cone 7 it takes about 10 -12 hours. I leave the peep hole and vent open in both firings until there is no steam coming from the peep hole, use a mirror to check this. Then I plug the holes and leave them in until I open the kiln about 20 hours after it has switched off. My biggest issue is getting a supply of of mini bars to operate the sitter.

Small cones work just fine. You don't have to have bars.

If you're not using a downdraft vent system, leave the top peep open for the entire firing. Moisture isn't the only issue, you need to vent fumes as well, which come out during the entire firing.

3 hours on each setting is longer than you really need to go, especially if everything is dry. You can go an hour on low and medium.

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Old lady lovely offer but I live in Ireland.

Neil I have difficulty with mini cones too.  Thanks for the extra info, good to know I can speed the process I will try that this weekend and I will leave the top vent open.

I am a novice and this website is my teacher, thanks to all for that.

 

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Sputty thanks for that the Potters Connection looks promising postage wise, and I will contact them about actual postage rates i have ordered from UK before, the issue always seems to be those who stock the cones I want charge excessive amounts for postage, last time I bought a box of cones from a company it was an ordeal. This tiny light box cost me £15 to ship and took 3 and half weeks to deliver. I worked out had this same company sent this box to Australia and someone in Aus sent it back to me it would have been cheaper and faster. My problem is I live in the north so I don,t get the standard European rates rather the excessive islands highlands and NI rates.  thanks Sputty

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1 hour ago, annacondagh said:

My problem is I live in the north so I don,t get the standard European rates

It's a shame Scarva don't stock them, then! They're usually quite helpful - I imagine you've already contacted them on the off-chance of them obligingly finding you some?

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