File puptcrit/puptcrit.0902, message 557


From: "Robert Rogers" <robertrogers-AT-robertrogerspuppets.com>
To: <puptcrit-AT-puptcrit.org>
Date: Wed, 18 Feb 2009 09:44:15 -0500
Subject: [Puptcrit] cementex how-to


My initial impatient comments last night (sorry) have ceded to my better judgement.  For anyone interested, here are some helpful hints that you will not find in the company catalogue:

How to use Cementex L200 & #64 Filler:

 

These products come in plastic gallon buckets with tight lids.  Use a similarly lidded plastic container for your mix.  (Eventually, you will have extra empty Cementex containers to use for all kinds of purposes.)

 

I mix them 1:1.  Don't bother with a measuring cup or a scale.  Eyeballing is sufficient.  Also, don't think that you have to combine both gallons.  Just estimate what you'll need for a project and store the rest.

 

You are not mixing a catalyst into an agent.  You are just mixing two products - like chocolate syrup and milk.  Stir with something disposable - or something that you won't mind coating and using again.  (Washing it off with water is not advisable.  The water will make little particles like from an eraser.)

 

A paint stirring attachment for a drill will create too many air bubbles.  If any bubbles form after mixing, just blow them off or wait a few minutes.  They're not much of a problem.

 

L200 is bright white; #64 filler is tan.  When there are no color streaks, you have mixed enough (generally a few minutes).

 

The consistency should be like heavy cream.  2 times in the last 25 years, I received bad batches that turned thick as mayonnaise.  I called the company and replacements were sent immediately.  (I was told I could have also just added some water.  But I tried it and it didn't work.)

 

Pour into your plaster mold.  The time needed to jell up depends on the size of your project and the dryness of your plaster mold - also how thick you want your finished piece to be.  Experiment.  I usually wait 45 minutes to an hour.  Small hands or feet can be less 10 to 15 minutes.  Use a timer and top off as the minutes go by.

 

Pour out the excess to use later.  Set the mold aside (do not think to speed things up by placing near a heat source or even leaving in the sun).  Wait over night.

 

Slowly separate your mold parts.  The form inside will be damp and soft.  You can place it on some cotton batting to air cure for a day or two (again depending on the size and the humidity in the air).  Or you can place it in an incubator for about 5 hours and it will be done.  I made one from a cardboard box lined with aluminum foil and a 60W bulb.

 

Turn object occasionally to dry all sides.

 

Use a dremel type tool with a felt polishing tip to remove flashing.  Or use a similarly large disc version that can be attached to a drill press (6 to 8 inches in diameter - found in woodworking supply stores).  You can also cut with an exacto knife or pair of scissors.  Sandpaper works fine too.

 

I paint with acrylics.  I don't need a primer.  Also, fresh L200/64 filler spread onto a cured cast will adhere like glue or fill in any problems. 



Good luck!  If anyone has any questions, I'll be glad to help.



Robert
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