[Diana Ferreira]

I have wanted to make hollow bowls for some time. But there is always something that is more urgent and a deposit has been paid for said work so this just got pushed into the back of the line. In the beginning of March I made the plaster molds, and yet again no time to focus on it.

But a week ago I decided that is it! I released the molds from the masters and casted the first and only one. I was scared. I am very anylitical and knows how many things can go wrong. And after I made the molds I realised that the dimensions were all out. But, I've got the mold, and used it. Anyway, here is the result:

Black hollow bowl with a white glaze

Attached File(s)

•  hollow bowl1.jpg (10.41K)
  Number of downloads: 105
•  hollow bowl3.jpg (6.96K)
  Number of downloads: 86
•  hollow bowl 2.jpg (13.34K)
  Number of downloads: 60

[Chris Campbell]

Congratulations on pushing through and getting it done ... it is sometimes a weird and background fear that keeps us from doing the new, fun stuff.
Let us see images as you progress through designs!

[Marcia Selsor]

Very nice. Are you casting with a black slip?
Marcia

[OffCenter]

Nice!

[Diana Ferreira]

Marcia, yes (and thank you :-). I use a black slip that my supplier makes up for me. Shrinkage is about 17%.
thank you Offcentre

[Matt Oz]

Looks good, nice contrast.
Is black slip expensive?

[INYA]

Looks great!

I know how many things can go wrong...


Have you heard for "Molduct tubing"?
I have found this old link: http://www.ceramicar...zonoExcerpt.pdf

even ordered some but never had the time...
btw have you maybe managed to check porcelain firing?

[Diana Ferreira]

Oh Damn, Inya! I have forgotten! But I promise that I will do so tomorrow - making a note on my phone :-) Sincere apologies.

I have seen that tutorial, and my ex do have some of the tape. But the slip that I use takes for ever to dry when it is completely enclosed in plaster. So my approach with this bowl was a bit different :-) (I even cast my plates into an open mold and decast after a set time. I do not add footrings to any of my work, hate them!)

Matt, I do not think that it is more expensive than stoneware. It is definitely much cheaper than porcelain slip :-) Because of the metal content in the clay, it is quite naughty. Blisters easily if fired a few degrees to high. It squats easily during a glaze firing. And the range where the body turns black is quite narrow (till it blisters). But, this is a local product I use. I do not know if all black clay bodies do this :-) My slip says earthenware, but I fire it close to stoneware temp to get it to go black black.

[SmartsyArtsy]

They look very nice. How large are they?

I don't know much about hollow forms but it would make sense to me to use the technique forgot beverage tumblers.

[Diana Ferreira]

Hi Chris, I know what you are talking about. Those insulating tumblers. That is on the agenda ... But again - it is difficult to release certain shapes, or you can get cracking as the clay starts to shrink before it releases from the mold. The clay I use is very soft even when it is loose in the mold, and I normally need to rest if for longer inside a mold, shrinking and hardening more before i remove it. This bowl is 12 cm x 7 cm and the rim is 3 cm wide.

[yedrow]

Very nice work!

[INYA]

no footrings, that is interesting
why?

I am not a fan either but I thought I am the only one.

I heard so many times that they are a must for various reasons

[Diana Ferreira]

My ex, who is a modeller and works for a large ceramic company in our city hates the fact that I refuse footrings. There is lots of reasons. Glaze a piece completely, but the footring is clean, and the glaze does not stick to the shelve. A piece with a footring will wobble less (well, it is supposed to wobble less if the mold is a good one). Your piece will not scrape the table and damage it if have a footring. Well, i sand my work at bisque and after the glaze firing so it is smooth.

I just really hate footrings. I almost never glaze the outsides of my work, so I have no problems with glaze sticking to the shelves. And my clay slumps a bit in the kiln, so it lays flat (where I want it to lay flat!) AND, I really really hate the ring it forms inside a cup or bowl. I use 1 part molds for my plates, so i will have to manually fill that ring if my plates had a ring. And my plates will slump a bit in the centre, which I would not be happy with.

I am glad there is someone else who does not like it :-) Rules, what rules? hehehehe

[Diana Ferreira]

Forgot to add: I started making molds this past weekend (we had a super-long 5 day weekend :-) to make another hollow bowl with dimensions that I will be happier with. one more master to cut, but I am low on plaster :-(

[Karen B]

INYA, on 29 April 2012 - 04:06 PM, said:

Looks great!

I know how many things can go wrong...


Have you heard for "Molduct tubing"?
I have found this old link: http://www.ceramicar...zonoExcerpt.pdf

even ordered some but never had the time...
btw have you maybe managed to check porcelain firing?

Most amazing article. So much patience. Thanks for posting.

[INYA]

I don`t like the rings that are formed inside too and I heard all the reasons why I should have footrings...

I am glazing outside but I only use one good tested glaze and I am rather spending time wiping it off or using wax. Anyway you have to wipe it off the ring also and it is not a piece of cake -for me it is the same you have a line ring/side or flat bottom/side.


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