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which pulp recipe for molds

#1 2010-04-16 14:11:08

bubblebev
Member
Registered: 2010-03-21
Posts: 6

which pulp recipe for molds

I have a few molds (which are only a few mm thick) that I would like to use to make decorations for boxes.  The trouble is I cant seem to make a pulp that I can put into the moulds that actually picks up the shape properly.

For example I have a simple thin heart mold but when dry and I remove it, it doesnt really resemble a heart as the edges are blobby where the pulp hasnt spread to the edges.

Which recipe is the best to follow in order to do the job best?  Could I make the pulp more watery and hope that it dries properly?

Thanks in advance for any ideas!

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#2 2010-04-16 18:29:01

CatPerson
Moderator
From: Washington State, U.S.A.
Registered: 2006-01-09
Posts: 1314

Re: which pulp recipe for molds

What are your molds made from?  Are they rigid or flexible?

I've never used pulp for a thin casting, but I wonder if you could press the pulp into the mold and let a little of it extend straight past the edge. Let dry slowly (moving air from a fan is okay, but no heat, it can cause warping).  Then cut or file/sand the extra bit around the edge down to the level you want.

Another method you might consider is using paper strips to line the inside of the mold for the first layer, then press your pulp onto that.

Adding extra water usually causes the form to shrink more when it is fully dry, in my experience, but maybe if you added just a tiny bit of extra water, it would help.

What kind of adhesive are you using?

Sue

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#3 2010-04-19 16:19:51

Patraw
Member
From: Michigan, USA
Registered: 2008-09-10
Posts: 151
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Re: which pulp recipe for molds

I use a mixture of tissue paper and white glue when I cast papier mache pieces from molds, rather than pulp or strips.  Take a small piece of the paper, glob some undiluted white glue on it, and then knead it in your hands until it has a clay-like texture (if it's too dry, add more glue).   Put it in your mold (I recommend putting some kind of mold release into the mold first, I use mineral oil) and then press it in with a liberal application of force, and then let it dry for several hours (preferably in the sun) before you remove it.  The side that was in the mold, which will probably still be damp, will then have to be left to dry as well.  There will probably be some excess flash to remove too.

Here's an example of this methodology that I used to make 7 of the 8 spider legs on my last project:

http://i5.photobucket.com/albums/y196/kramwartap/DoO_zariche_legmolding.jpg

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