[Clayart] BISQUE FIRING

[don jung]

Hi Ken,
I've left my pots to dry for weeks...some for months but note that I'm in
Vancouver, Canada and it's well into the rainy season.  So dry and drying
time are all relative.  During the summer and if I don't fire big pots, I
don't run into these bisque firing issues as much.

cheers,
Don


> Date: Sat, 28 Nov 2020 07:12:02 -0800
> From: Ken Chase <kchase235 at gmail.com>
> To: Clayart international pottery discussion forum
>         <clayart at lists.clayartworld.com>
> Subject: Re: [Clayart] BISQUE FIRING
> Message-ID: <74CA5D99-118F-40CD-B6F1-27B30F43D2F2 at gmail.com>
> Content-Type: text/plain; charset=utf-8
>
> I?m curious. How long do your pots dry before you fire?
> Thanks
>
> Sent from my iPad
>
> > On Nov 27, 2020, at 7:49 PM, don jung <donjung88 at gmail.com> wrote:
> >
> > ?This discussion has been interesting since I asked a similar question in
> > the past.  I constantly monitor my bisque firings and have noticed a few
> > things.
> > My last firing, I held the temp at 180F (bottom dial not even 1/2 way
> from
> > Off to Low) until no vapor appears in a cold glass jar (similar to the
> > mirror technique).  Took about 4 hours!  I then turn up the heat (bottom
> > dial to low) and watch the temp rise.  It gets to about 250F and out of
> > routine, I do the cold glass jar check.  Guess what, more vapor than
> ever.
> > I backed it off to 200F and hold until no more vapor (about another hour)
> > and turn up the heat again.  At 250F, there's still vapor, but I
> > decided not to turn it down...just held it there till no more vapor
> > (another hour).  Turning it up again, there's no more vapor at 300F and
> it
> > fires normally.  Checked my thermometer and it reads correct temp.  The
> > temp probe was positioned in the top spy hole, maybe bottom spy is better
> > indicator.  Also difficult to get a reading in the middle of a pot in the
> > middle of the load.  What was throwing off this firing was probably that
> I
> > had a very large planter pot in this firing.  I think I'll stick to my
> > regular sized, thrown pots as they fire easier.
> >
> > cheers,
> > Don
> >
>
>
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