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plaster tip # 9 (smooth/shiny plaster)

updated tue 28 oct 03


Jeff Longtin on mon 27 oct 03

Working in the studio last weekend, working on some prototypes, and a little
used technique became useful that I thought I would share.

The prototypes that I was working on were intended to have flat smooth
(I want to reproduce these prototypes in plaster so I can set the original
aside while I work on production molds.) Due to the design of the forms the
poured plaster surface would make up the bottom of the finished piece so I needed
to get the bottoms as smooth as possible.

Here's the tip: After the plaster has set, between 10 and 20 minutes
(depending on the age of the plaster), take a clean sponge (this is presuming you used
a flat metal scraper to level the surface before it hardened) and lightly
sprinkle the plaster surface with clean (drinkable) water. Before the plaster has
a chance to absorb all the water lightly scrap the surface of the plaster
with the metal scraper. Wait about 10-15 seconds. Apply more water, scrap. Apply
more water, scrap. Do it one more time and you should see the surface of the
plaster develop a nice sheen. Do it a few more times and you may even get a
shiny surtface.

(I helped a friend pour a wedging table years ago and she was amazed that I
was able to get the poured side as smooth as the molded side!)

Also, if, as you scrap, you notice you're starting to break through the
slight skin that forms on setting plaster, than just stop and wait a few minutes.
Waiting longer than not is not the worst thing, it just takes a little more
effort to scrap the now harder surface.

A nice little trick when it works out right.

This, btw, is a nice technique when you are patching holes in sheetrock
walls, as well.

take care
Jeff Longtin
in "cool" minneapolis