| Setting Out Your Work:
Before you bring water anywhere near your ModRoc plaster of paris bandage, set out
the artwork or model carefully. Preparation is most important if you want to ensure
that you make the best use of your ModRoc. Remember that once the ModRoc is wet it
takes a few minutes before it starts to harden and then for a few more minutes you can
mould and work it before it gets too hard. So speed of working is important which is
why you have to think out what work you want to do before you start wetting your plaster
of paris bandage. Storage is equally
important. Take out of your container, or if sealed individually open only what you
need. Keep the rest sealed in an airtight container and store in a dry cool
place. Any contamination with water makes it un-useable later. With careful
storage, the shelf life can extend to years.
How Much to Soak: If you are making a large,
hungry model, which is easy to layer with quantities of plaster bandage, you might be able to soak
a roll at a time if it is a small one like for example the12cm or 10cm x 2m rolls. A
large roll like the 20cm x 4m roll will have to be slit or cut into lengths to suit the
shape you are working on. Each cut length can be folded zig-zag or rolled up (I
prefer zig-zag because it unfolds easier when wet). Small or fiddly models
necessitate cutting up short lengths to soak and work with, bearing in mind the workable
time of the Mod Roc.
Soaking: The process of soaking and modelling
is best done by hand. It is a tactile process. If you use gloves, however
thin, you lose contact with your work. As far as I know, Plaster of Paris
bandage is non allergic and it is easy to wash off when you have finished work. Soak
the roll in tepid water (the warmer it is the quicker it sets) for about 5 seconds until
it is saturated or the bubbles stop rising (trial and error).
Squeezing:Gently squeeze out excess water or let it
run off for a few seconds.
Wrapping and Layering: Immediately after
squeezing, gently wrap or drape the bandage over and around the frame or object, layer
upon layer. Don't wrap it tightly.
Shaping: Shape the bandage by hand
continuously during wrapping in order to make the bandage adhere and to remove bubbles and
cavities. When it begins to harden the shaping process should stop it will
reduce adhesion.
Setting: The normal setting time is 2-5
minutes but can be changed slightly in the following way. to accelerate setting, use
warmer water or after layering, a hair dryer or heater. You can retard setting by
around 4 minutes by using cooler water and by adding 2mg sodium sulfite (anhydrous) per
1000ml of water before soaking.
Preparation for Painting: If you intend
painting your work I have some important tips for you.
- The surface of ModRoc is normally crumbly so paint will easily pick
or rub off even after it dries. My solution is before soaking the bandage, mix about
1 part of PVA glue to 2 parts of water for soaking. This has 2 effects, one is
(if you want it to) it sticks much more firmly to the base material of your model. The
second major benifit is the PVA bonds the Plaster of Paris much more tightly together so
it will not flake off as easily when dry. It does not retard the drying of the P of
P bandage.
- Prepare the ModRoc for painting as you would a canvas. I use
Leyland Acrylic Primer Undercoat. This can be used for both oil and acrylic paint.
- Use good artist quality paints. I prefer System 3 Acrylic or
Windsor and Newton Galeria. Now you can also buy Acrylic paints
from Craftmill. We have
top quality Acrylic craft paints and also Artist quality high pigment
loading artist paints
- For protection, varnish the finished work with the appropriate
varnish. Commercial quality varnishes work perfectly well for example
Johnstone's quick dry acrylic varnish if you used a water based paint.
Smaller quantitis fro hobbyists and jewellers can be bought from our
internet shop Craftmill
I hope these tips prove to be helpful
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