[cstovin]

Hi All,

I have searched and looked at other threads, and found that most people recommend vaseline or tincture of green soap, or murphy's oil soap as a release agent when making a plaster of paris mold from a bisque piece.


I googled this topic and watched a few video's on how to do it, but I didn't find exactly a tutorial or video for ceramic bisque - so my question is - how do you do this when using ceramic bisque?


Do I

1) Mix the plaster of paris as indicated

2) coat the bisque piece with release agent and place it in the bottom of my mold tray, mold facing to be duplicated side up

3) pour plaster mix delicately around and eventually over the top of my bisque piece

4) wait until plaster starts to harden (need more information on this, carton says to wait an hour....??)

5) flip over and remove bisque piece

6) let plaster mold harder 24 hours before using



is that the correct process? I guess my question is I am not sure how to use the release agent. I am assuming I just cover my piece that is intended to be duplicated (bisque)?

Any information is much appreciated

thank you

C.

[Cass]

i use olive oil, but any (non toxic) oil will work

this sound like a one piece press mold...are you doing a tile or something?

an hour seems right, youll be able to tap it, but unless you are in a hurry...wait for it

no worries, its pretty hard to mess up...if its a bisc piece you can always try again anyhow

[Marcia Selsor]

Why use bisque?
1. It has shrunk 5%
2. Any undercuts will break unless you make two or more piece molds.
3. You may need to use a coating that will not be absorbed by the porosity of the bisque....more like a coating of paint or shellac to prevent the absorption
Of the release agent.
Just some things to consider.

marcia

[cstovin]

I found a bisque piece that I like, it is a small oval tile for lack of better description that has a butterfly scene on it, the other like it has a hummingbird on it, but I wanted to make my own mold for them, so I can press clay and make duplicates to raku; that was the purpose; they came from a local ceramic store that does not sell greenware, nor do they fire to cone 06 for Raku, so I thought it should be easy to make my own or make a mold from them....


they were inexpensive, so thought I would give it a whirl.

thanks both for the help
C.

[Mark C.]

The bisque is porous all you need really is to seal it-any release agent will work-as noted above shellac works good-I personally do not use oil as it can get on the plaster a tad-I am a green soap or mold soap (buy by the gallon) guy-so after sealing I soap it and pour the plaster.
good luck.
Mark

[Lucille Oka]

As Marcia has stated you will experience quite a bit of shrinkage through all of the steps to completion.

I had to remove the other part of this post; because of guilt.

This post has been edited by Lucille Oka: 23 October 2012 - 04:06 PM

[scoobydoozie]

cstovin, on 21 October 2012 - 07:43 PM, said:

I found a bisque piece that I like, it is a small oval tile for lack of better description that has a butterfly scene on it, the other like it has a hummingbird on it, but I wanted to make my own mold for them, so I can press clay and make duplicates to raku; that was the purpose; they came from a local ceramic store that does not sell greenware, nor do they fire to cone 06 for Raku, so I thought it should be easy to make my own or make a mold from them....


they were inexpensive, so thought I would give it a whirl.

thanks both for the help
C.

The piece is probably copyrighted and you should be looking for the company that makes the mold rather than creating your own and infringing on the copyright.

This sounds like the inserts made by Dona's Molds. Those molds/masters were sold to Indiana Ceramic Supply and you can still order the plaster casting molds from them for about $15 each.

Here's a link the butterfly: http://www.debmark.c...art=14957#start
And, here's the link to the hummingbird: http://www.debmark.c...art=14944#start

Let me know if these are the correct pieces. If not, post a picture and I'll try to find the molds for you.

[Lucille Oka]

Scoobydoosie is absolutely right. I felt ashamed after I posted my response. I have contributed to this delinquency; and it may indeed be an infringement of a copyright. Cstovin, try to make your own bird tiles it is not hard to do and making the molds will be easier and better.

[neilestrick]

I you need a tile of a specific size, make an original that takes into account the shrinkage rate of your clay. Make your mold when the tile is leather hard. We just use watered down liquid hand soap as a release. Works great. Carving a tile is not terribly difficult, and you'd have a piece that is 100% your own creation.