Veena Raghavan on wed 9 jul 03
I would appreciate any help or advice on firing containers with a screw
cap. Does this not in fact create a closed form with the danger of cracki=
ng
or exploding, if the container is fired with the cap on. Also, is there n=
ot
a problem with the clay fusing (as in stuck lids) in the grooves of the c=
ap
and container. I guess one could use wax and ilumna for the grooves, but =
I
am still worried about the closed in air.
If anyone has any advice to offer, it would be much appreciated.
Thank you in advance.
Veena
Veena Raghavan
75124.2520@compuserve.com
Snail Scott on wed 9 jul 03
At 03:25 AM 7/9/03 -0400, you wrote:
>I would appreciate any help or advice on firing containers with a screw
>cap. Does this not in fact create a closed form with the danger of cracking
>or exploding, if the container is fired with the cap on...
I would be surprised if it were possible to create a
truly airtight screw top. Air can escape through very
small crevices, and even the tiny gaps between the
threads should be sufficient to prevent destructive
pressure buildup.
-Snail
David Hendley on wed 9 jul 03
Fire with the cap off the pot.
Screw threads made from clay are not very precise, and a screw-on
cap will not create an air-tight closed form.
Clay fusing, however, could be a problem, so fire with the cap off
and don't worry about it.
For bisque firing, it doesn't matter, fire on or off.
BTW, your bottle with the screw-on cap will not be liquid-tight when
fired, either. If you want that, you have to incorporate a rubber or cork
seal into the design.
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
I would appreciate any help or advice on firing containers with a screw
cap. Does this not in fact create a closed form with the danger of cracking
or exploding, if the container is fired with the cap on.
pdp1@EARTHLINK.NET on wed 9 jul 03
Well, too...so long as there is no Glaze on the 'threads'!
Eeeeeeeek!
Phil
lasvegas
----- Original Message -----
From: "Snail Scott"
To:
Sent: Wednesday, July 09, 2003 9:54 AM
Subject: Re: Firing jars or bottles with screwed on caps
> At 03:25 AM 7/9/03 -0400, you wrote:
> >I would appreciate any help or advice on firing
containers with a screw
> >cap. Does this not in fact create a closed form with the
danger of cracking
> >or exploding, if the container is fired with the cap
on...
>
>
> I would be surprised if it were possible to create a
> truly airtight screw top. Air can escape through very
> small crevices, and even the tiny gaps between the
> threads should be sufficient to prevent destructive
> pressure buildup.
>
> -Snail
>
>
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Hank Murrow on wed 9 jul 03
Dear Screw-top Lovers;
Thanks to a fellow Clayarter in CO I was able to borrow a Bluebird tap
& die set and try my hand at making screw-top lids. It took around
three ware boards-full to get the hang of it, but I did wind up with a
threaded lid which was sealed with a leather disc. Worked pretty well,
but I prefer to have no threads inside the cap, so I retain my caps
with a bamboo skewer now, and find it both aesthetically more pleasing,
and easier to pour, and the cap can be used as a cup. So I returned the
tap & die set, though folks keep asking about those 'threaded bottles'.
You may see the result at
http://www.murrow.biz/hank/hankweb-all/page1.htm , #011.JPG. Ever since
Piccolopasso, potters have toyed with this idea.....it is seductive,
but not necessarily productive.
Cheers, Hank in Eugene
BTW, I fired the caps on, as well as off, and had no trouble either way.
On Wednesday, July 9, 2003, at 12:28 PM, pdp1@EARTHLINK.NET wrote:
> Well, too...so long as there is no Glaze on the 'threads'!
>
> ----- Original Message -----
> From: "Snail Scott"
> To:
> Sent: Wednesday, July 09, 2003 9:54 AM
> Subject: Re: Firing jars or bottles with screwed on caps
>
>
>> At 03:25 AM 7/9/03 -0400, you wrote:
>>> I would appreciate any help or advice on firing
> containers with a screw
>>> cap. Does this not in fact create a closed form with the
> danger of cracking
>>> or exploding, if the container is fired with the cap
> on...
>>
>>
>> I would be surprised if it were possible to create a
>> truly airtight screw top. Air can escape through very
>> small crevices, and even the tiny gaps between the
>> threads should be sufficient to prevent destructive
>> pressure buildup.
Fredrick Paget on wed 9 jul 03
Screw thread tops on ceramics are a bad idea.
Ceramics are like concrete, strong in compression but weak in tension.
When you tighten up a screw down top you are putting a tension load
on the threads and they can easily break.
For a liquid tight closure on bottles do like the old timers did: use
a cork or if there is reason to get fancy like the old stoneware root
beer bottles with pressure inside use one of those wire thingies that
lever the cap down on a rubber or cork washer.
You can make a nice ceramic cork cover like a hat that covers the
part of the cork that is out in the open, Looks real professional.
Fred
--
From Fred Paget, Marin County, California, USA
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