[Can I bisque fire twice?]

What temp did it reach after the initial 2 hours?

It will be interesting to see how your pots fared.

[Zinc oxide]

When I asked the question I was remembering a,lengthy posting on Zinc oxide. Fortunately? today I found I did have the dense zinc oxide in my supplies as well as a white powder. The dense Zinc Oxide was an off white, old supply.

Recipe I was going to try calls for

ZnO                     25

Pot Feldspar  40

Ball clay              5

Calcite                15

Silica 2oo           15

What does anyone think..desc nice domestic glaze with the addition of 4 part iron..olive honey colour.

 

[Zinc oxide]

Thanks Callie, not going for a crystalline glaze but having written that, the glazes I was reading through were matte.

[Zinc oxide]

Just flicking through old recipe book.

Can dense zinc oxide be substitued by zinc oxide?

Can't remember if i have any dense left in my shed.

[3rd firing gives more shrinkage? Controlled cool affect my other glazes?]

2 hours ago, Min said:

Nope.

A third firing to ^03 can definitely change the look of glazes fired to mid or high fire. In effect what you would be doing is a strike firing which can alter glazes high in colouring oxides, particularly with iron or copper.

Thanks Min , will go with the same procedure as before, drat it!! 

Might unleash a new amazing range though! But ....

It was a copper clear at c5 turning to a "matte" at refire to C03, slip added prior was a copper/ MnO2 thing, only on outside of pot .

 

[3rd firing gives more shrinkage? Controlled cool affect my other glazes?]

To save time I was going to try a controlled cool of my normal C5 firing . My second question is will this jeopardise the otger glazes in my kiln.

[3rd firing gives more shrinkage? Controlled cool affect my other glazes?]

33 minutes ago, Bill Kielb said:

It sounds like the clay was fired to cone 5 and then cone 5 glaze was applied and fired to cone 03 which makes it simply an under fired glaze,  so very matte, but only two glaze firings. Maybe I am reading this incorrectly. If you have a low fire glaze that is matte and very close, or perhaps an acceptable contrast then for the sake of speed,  I think I would make the lid with a relatively broad gallery out of clay you are used to, so easy to fit, fire the clay to cone, then apply the low fire matte glaze and fire to its cone.

I might be misunderstanding though.

Sorry, I glazed it fired it to C5, to maturity, then refired to C03 with added oxide brush work. The clear glaze turns "matte". Years ago...

Now I am making 3 lids but only have the measurements of finished pot, photo, pot other side of the country.

Just wondering if there is significant shrinkage occuring at the second glaze firing.  And my other query.

Thanks Bill.

[3rd firing gives more shrinkage? Controlled cool affect my other glazes?]

I have been askedx100 to try to make a replacement lid for a teapot. That specific teapot was fored to cone 5 , clear green glaze,then fired to c 03 which made glaze a microcrustalluzed glaze,"opaque".

Will that 3rd firing cause more shrinkage?

Or if I do a controlled cooldown  what type of glazes may also be altered in that process?  Guy wants it quickly...

I know, I know...

[Trying to find a glaze book]

9 hours ago, AJP said:

I'm trying to find what book these recipes came from. Found these in an old text book my professor made. Does anyone recognize the font/style? Would love the whole book.

Thanks

 

book.pdf 684.05 kB · 8 downloads

Looks like one man's collection of other folk's glazes, prob no text book as such

Some are Bwenard Leach's , some are Val Cushings , you say they are your professor's so why not ask him?

[How do I know if bisque is underfired?]

Ifit was bisqued to a lower temp. it will take on more glaze if glazed as usual. Maybe test fire one glazed piece through a normal firing, place it on a clay biscuit to protect your shelf.

[Venturi burners backburning]

Get a meter and regulator, ( which you can adjust at fractions of  psi ),  in line, trying to regulate at cylinder too "gross" if thats the right word.

Might be domeone who can send a pic of their set up.

Psst, move your burner back a tad.:))

[Venturi burners backburning]

17 hours ago, Brett said:

Thanks Bill - I will  put a hand operating valve upstream of the burner as you suggest, and take into account all the other information supplied by you and others. Thanks again!

Think that's a must.  I operated the first part of firing by using a pilot light, could be pretty vigorous but burner too vigorous for 1st part of my firing. After the cylinder regulator,  inside my shed, a shut off lever,  the gas control valve with pressure indicator was next, an air intake was next in line, then  down to the burner. Never touched the air intake at burner.

Just saying.

Good luck. Depending what neck of the scrub you are in there would be gas firers nearby who could twig what is wrong in the setup you have.

Have you been firing this kiln successfully and this burner issue has just arisen?

[Venturi burners backburning]

The image you show saying it is not backburning, the flame is orange and"woosy", not a fle I'd like to see when firing,  what makes you write it is backburning with the blue flame image, is it making sucking back and gurgling sounds in the burner head?

[Venturi burners backburning]

A possible danger where it is is that the heat sensor / gas switch off mechanism may be affected by the interior temp of kiln emanating from the orifice not the loss of flame from burner. Do you have another air conrtoller up the line?

Whats the flame path like inside and the suck of the stack/ damper at other end?

Will be a play between all of the above

[Venturi burners backburning]

Back in the day , burner,shown is way too clise to kiln and is actually in the kiln, set it back out from the kiln a ways so air can be drawn in around the orifice to kiln and thus the flame. I'd start there, and flaps open as Mark says

[Positive about failing elements.]

No, freight not included in that amount! Just how it is here. Sheath for a long gas kiln s thermocouple, $70 many years ago...middle factor making the $

[Cleaning a wax applicator]

You haveto insert the wire as soon as you stop using the wax.

If blocked hot soapy water and inserting and turning the wire a number if times would do the trick. A goid quality liquid wax would be the best.

A  hot wax applicator , used for batik art, a tjanting, is ok but need skill, eh !0

[I believe I over-fired]

Yes the higher bisque is prob main reason if not the only one. Your ware would not have the same thickness of glaze and so would take on a different appearance. See the recent post re mistakenly firing to cone 5 bisque by Elaine Clapper

Are your cones significantly different than previous firings?

[What's a fair price for this kiln?]

Sounds for the best. The pointmade re electricity supply  and 3 phase is worth noting. Unless your property has 3 phase supply best to stick with single phase kilns imo.

[What's a fair price for this kiln?]

Think the bottom element hasn't been replaced at same time as others, looks older and poss faulty. Can it be plugged i n and switched on at full for 15mins to find out if they all fire up.

Could be up for new elements too.

 

[What's a fair price for this kiln?]

Looks like the lid has not lifted on heating, at the hinge , and has crushed the bricks, putting the element at risk .

That's a pity. Any new element will be at risk unless those bricks and groove liners are replaced.

Better factor that into the price you are willing to pay.

[Cleaning a wax applicator]

Is your applicator already blocked?

What kind of wax are you using?

Most applicators come with a very fine wire which is inserted after use.

[I can't believe I accidentally fired my bisque load at cone 5!!]

What temp/ cone does your clay fully vitrify?

Unglazed, rough folk seem to like these days.

Could brush and wipe an oxide wash and refire the stuff, to top temp recommended,  suited to that.

[I can't believe I accidentally fired my bisque load at cone 5!!]

Depending on the ware, you could paint it.......down the line a bit!

[Corn stalk ash?]

5 hours ago, Biglou13 said:

Thanks Babs.  Good to see some familiar names still here! 
 

that’s a huge amount of stalk to ash.  Sounds like more work than I’m prepared. To do.  

Great to read you are still experimenting!!

Thinking of Euan Craig,  I think he lays actual rice stalks onto his platters before his firing https://www.instagram.com/p/CETiWhODEv4/?igshid=NTc4MTIwNjQ2YQ==