# Plaster questions, any artists (or concrete workers) out there?

**URL:** <https://boards.straightdope.com/t/plaster-questions-any-artists-or-concrete-workers-out-there/130181>\
**Category:** Factual Questions\
**Created:** [September 30, 2002, 1:48am UTC](https://boards.straightdope.com/t/plaster-questions-any-artists-or-concrete-workers-out-there/130181 "2002-09-30T01:48:17Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\
**Post date:** [September 30, 2002, 1:48am UTC](https://boards.straightdope.com/t/plaster-questions-any-artists-or-concrete-workers-out-there/130181/1 "2002-09-30T01:48:17Z")

</div>

Okay, this is an oddball situation, but here goes…

Earlier tonight I poured some plaster models that I’m going to use as lasts for doing leatherwork (FYI, the plaster I used was Ultracal 30, a plaster and Portland mix.) After talking with a few local artists, I used Murphy’s Oil Soap as a mold release. Now as the plaster cooks, I’ve got a few questions:[ul][_]I want to use these ASAP. Is there anything I can use to seal the surface that will have a curing time of 24 hours or less and won’t attack the plaster? I’m thinking about using thinned polyurethane, but wouldn’t mind a better suggestion.[_]What removes Murphy’s Oil Soap? Will water dissolve the plaster or drive the soap into the plaster? Will paint thinner work?[/ul]