Jump to content

Recommended Posts

I recently began experimenting slip casting using commercial molds. One particular mold, the handle of the cup ,which is a neat little circle gets stuck everytime I take it out and then it breaks off. Is there a release agent I can use that will make the releasing process easier without hampering the osmosis between the clay and the plaster. Please advise ??

Link to post
Share on other sites

No release agent for plaster moulds, that I know of.

Have you checked that the mould is clean?  Try vinegar and a sponge to clean it up.

Does your slip release easily from other moulds? 

Are you leaving it too long before un-moulding?  Too little time?  Casting too thick, too thin?

Small curved moulds are the devil to deal with.  I have had to enlarge the "funnel" on handle moulds as they never held enough "top-up" slip.



Link to post
Share on other sites

That cup handle is often cast alone and added later.

The tricks are dry mold very well before use-after dumping it our pull it apart when cup is ready-time this on a timer. Do not leave overnight-take it apart when clay in handle has some give to it. The reason its cracking is is shrinking  onto the inside cast part of the handle.The idea is to get it out before it grabs the inner part.This type of cup with handle is a hard top deal with mold to get a handle cast to body in one pour.

many cup molds added the handle later as that is easier.

Link to post
Share on other sites

Thanks Mark for your advice.I did attach the cracked off handles with some casting slip and I am surprised how well it binds after dipping the cup quickly in water.Just hope it will survive the firing. I also have another mold I want to use .It is a candle holder but it does not have a pouring cup .How do you cast that one?.Do you fill the one half with slip, put the other half on top and rotate it to get an even layer inside.?Please advise it is like casting blindfolded.

Link to post
Share on other sites
  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.