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Using molds


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#1 sad duck

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Posted 11 March 2013 - 03:35 PM

I have made several molds and I'm having trouble with them sticking! Earthenware clay bisked it,using Earthenware clay. I put spray cooking oil on the mold, still sticks! Any one know what I'm not doing right? Sad Mud!
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#2 Marian65

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Posted 11 March 2013 - 03:48 PM

I have made several molds and I'm having trouble with them sticking! Earthenware clay bisked it,using Earthenware clay. I put spray cooking oil on the mold, still sticks! Any one know what I'm not doing right? Sad Mud!


I use metal and glass and one old two-piece plaster mold, all as press molds. I use plain ol' Argo Corn Starch, brushed into all the little parts of the design and so far it has worked great. Any corn starch left on the piece cooks off in the bisque firing. I used a cheap cooking spray on a metal mold when I first started using it. It stayed sticky after many uses, so I just started brushing corn starch over it and keep on using it. Maybe the earthenware is still too porous to use for a mold. I'm not knowledgeable about earthenware, but someone is certain to give you a better answer soon!

#3 weeble

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Posted 11 March 2013 - 05:17 PM

What sort of mold are you talking about, sad duck?
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#4 Mark C.

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Posted 11 March 2013 - 08:41 PM

First I would like some more info-is this a two piece mold and you are pouring slip into or a mold your are press molding clay onto?
Is the mold made from plaster? or something else?

Also do not ever use oil of any kind on plaster as it seals the surface so the plaster can no longer soak up the water from clay and it will not dry out and release.
The more details you can add the better we can help
Mark
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#5 justanassembler

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Posted 11 March 2013 - 08:52 PM

First I would like some more info-is this a two piece mold and you are pouring slip into or a mold your are press molding clay onto?
Is the mold made from plaster? or something else?

Also do not ever use oil of any kind on plaster as it seals the surface so the plaster can no longer soak up the water from clay and it will not dry out and release.
The more details you can add the better we can help
Mark


I believe OP was trying to say she is attempting to use a bisque mold +1 for never using release agents.

#6 Mark C.

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Posted 11 March 2013 - 10:24 PM

Ok if you made a mold using clay and bisque fired it and then sprayed it with oil and clay is sticking -just rebisque fire it to burn oil off. Then only use corn starch or talc as a release as noted in above post-no more oil.
Mark
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#7 sad duck

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Posted 12 March 2013 - 10:36 PM

Thanks I will try the corn starch.


[quote name='Marian65' date='11 March 2013 - 02:48 PM' timestamp='1363034904' post='30764']
[q


uote name='sad duck' date='11 March 2013 - 03:35 PM' timestamp='1363034119' post='30761']
I have made several molds and I'm having trouble with them sticking! Earthenware clay bisked it,using Earthenware clay. I put spray cooking oil on the mold, still sticks! Any one know what I'm not doing right? Sad Mud!
[/quote]

I use metal and glass and one old two-piece plaster mold, all as press molds. I use plain ol' Argo Corn Starch, brushed into all the little parts of the design and so far it has worked great. Any corn starch left on the piece cooks off in the bisque firing. I used a cheap cooking spray on a metal mold when I first started using it. It stayed sticky after many uses, so I just started brushing corn starch over it and keep on using it. Maybe the earthenware is still too porous to use for a mold. I'm not knowledgeable about earthenware, but someone is certain to give you a better answer soon!
[/quote]
Sad Duck

#8 sad duck

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Posted 12 March 2013 - 11:15 PM

Yes that is what I did, thought I was doing the right thing so would not stick! Thank so much! Will follow your instructions!!


Ok if you made a mold using clay and bisque fired it and then sprayed it with oil and clay is sticking -just rebisque fire it to burn oil off. Then only use corn starch or talc as a release as noted in above post-no more oil.
Mark


Sad Duck




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