Dolita Dohrman on fri 2 oct 09
I have been glazing all morning and had a bit of a surprise. Many of
my pots have folded over or rolled rims which means some air can get
trapped. However, there is really no use in putting a pinhole in the
rim as you never know where the small air pockets are. Till today,
this has never been an issue. I had glazed the inside of the pot
yesterday and had dipped the outside this morning. I started to wipe
the glaze off the rim as I was going to spray it with another color.
All of a sudden I hear this pop, ping and a piece of the rim becomes
a projectile, arching in the air and landing about 4-5 ft. away! I
have never had this happen before. The piece was bisqued last week.
I have put a pic on flickr.
Has anyone else ever had this experience and do I now have to worry
about all those pots out there I have sold? One does not want to be
known for exploding rims!
Dolita in Kentucky
http://www.flickr.com/photos/35976669@N05/sets/72157622500989698/
Snail Scott on sat 3 oct 09
On Oct 2, 2009, at 2:08 PM, Dolita Dohrman wrote:
> Many of
> my pots have folded over or rolled rims which means some air can get
> trapped....I started to wipe the glaze off the rim ...
> All of a sudden I hear this pop, ping and a piece of the rim becomes
> a projectile... The piece was bisqued...do I now have to worry
> about all those pots out there I have sold?
Bisque is not as strong as vitrified clay, so
if it didn't break as bisque, the finished pieces
will probably withstand any residual stresses.
-Snail
Liz Willoughby on mon 5 oct 09
Hi Dolita,
I used to make a lot of bowls with the rolled over rim, and still do
occasionally. I found that if I did not use a pin to let the air out
when it became leather hard, the rim would quite often open up
somewhere at the edge where the rolled over rim was touching the main
form. Sometimes it was hardly noticeable. The trouble would happen
when I glazed a piece that that happened too. If glaze got in that
space, during the firing it would really crack along the rim. When I
glaze a bowl with a rolled over rim, with that tiny pin hole in it, I
seal it over with a little glaze just with my finger, before glazing
the whole bowl. I think that what might have happened in your case,
is that it wasn't a tight seal, and some glaze got in that space with
not enough room and it just dramatically broke.
Not sure if that is what happened, just my two cents.
Liz Willoughby
Grafton, Ontario, Canada
where the sun is shining, and the leaves are turning beautiful autumn color=
s.
At 3:08 PM -0400 10/2/09, Dolita Dohrman wrote:
>I have been glazing all morning and had a bit of a surprise. Many of
>my pots have folded over or rolled rims which means some air can get
>trapped. However, there is really no use in putting a pinhole in the
>rim as you never know where the small air pockets are. Till today,
>this has never been an issue. I had glazed the inside of the pot
>yesterday and had dipped the outside this morning. I started to wipe
>the glaze off the rim as I was going to spray it with another color.
>All of a sudden I hear this pop, ping and a piece of the rim becomes
>a projectile, arching in the air and landing about 4-5 ft. away! I
>have never had this happen before. The piece was bisqued last week.
>I have put a pic on flickr.
>Has anyone else ever had this experience and do I now have to worry
>about all those pots out there I have sold? One does not want to be
>known for exploding rims!
>Dolita in Kentucky
>http://www.flickr.com/photos/35976669@N05/sets/72157622500989698/
--
Liz Willoughby
2903 Shelter Valley Rd.
Grafton, Ontario
Canada
K0K 2G0
905-349-3130
lizwill@phc.igs.net
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