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Restoring Fragile Collectibles
By DiAnna Tindell
Wouldn't it be painful to select a mold material, spread it all over an area
of a frame to be copied only to see all the paint, design detail or gold peel
off as the mold is carefully lifted? To avoid such a problem, first consider a
mold release conditioner application over the area to be copied. A mold release
product basically works as a barrier between the original surface being copied
and the application of the mold material. Unfortunately, you can't always use a
mold release agent due to the delicate nature of some surface types, the
long-term effect that barrier may have on the surface, or the reaction it may
have to future processes.
Why the need for different types of molding
materials? With all the different body types that exist for collectibles, it is
helpful to have a variety of restoration products from which to choose. For
instance, some molding materials contain a petroleum base that can leave an oil
stain, especially, if the area covered is porous or absorbent. Other problems
that may be avoided by using compatible molding materials are damage to paint
surfaces, loss of gold or other metallic applications, breakage, warping or
insufficient detail.
Why the need for different types of casting materials?
In order to duplicate a missing area, casting material needs to be a compatible
match to the existing body type. As an example, there is a frame restoration
project illustrated in this article's photos. A Dental Alginate Impression Mold
material and a Dental Castone product will work well together for the
restoration of this frame. The goal for the restoration of this frame was to
allow all the worn, weathered and aged areas to remain. The surface areas of
this frame are soft bodied and fragile. There are a few mold materials that
might offer a safe duplication, but for this project, a Dental Alginate
Impression Mold material was used. You may be familiar with this product as seen
used in forensic molding on many TV crime investigation shows.
For this
project, we used the Alginate mold product to cast missing leafs from some
perfectly good ones already on the frame. Then, we placed the Alginate mold in
position to capture the protruding wires within the fill of a Dental Castone
formula. We mixed some color pigment into the Dental Castone so the new leaf
parts would already have the base match. Other places on the frame were in need
of some leveling, reinforcing and filling, so we used a more formulated Dental
Castone product for a portion of those techniques. After only a short drying
time, we were able to sand some areas for a smoother flow into the original
surfaces.
Our final touches involved the mixture of an airbrush liquid gold
to sparingly coat a few newly formed areas. As a blending faux finish process,
our final attention to detail was to apply small areas of wax gold and color to
create highlighted shine as needed to match the original gold. Careful attention
was given to avoid excessive restoration, leaving almost all of the original
aged surfaces.
Alginate products are available in different types for slow,
normal and fast set. It also can be changed by the use of either cold, warm or
hot water. The beauty of alginate is how gentle the material can be, no release
agent should be needed, and it is virtually harmless to most surfaces. After
all, it is a dental material safe for use in the mouth.
It comes as a fluffy
powder that is measured in ratio to water. Spatulate for approximately 45
seconds to produce a smooth, creamy mix. There is approximately two minutes of
working time to position the mix over an area to be duplicated. Let it set for
about one minute. Break the seal and lift off the alginate mold to be cast later
with a filler for the new part. The initial mold setting time is approximately
two minutes 15 seconds and total set at 3 minutes 45 seconds.
Alginate molds
can be stored in an air-tight zip loc bag and kept in refrigeration for a few
hours until ready to be cast. If you are trying to produce a smaller part from a
larger mold, you can use alginate in a series of shrinkage steps that can be
complex, but worth the final results. Alginate mold material is economical and
easy to use. One container (454 grams/1450 ml) can allow for the duplication of
many molds. The shelf-life can be well over a year if stored at normal temps and
low humidity.
Dental castone is a lot different than various brands of
chalk, plaster, etc., found in hardware stores. Many hardware store plaster
compounds will eventually shrink and deteriorate over time. Dental castone has a
compression strength of 3,000 psi wet and 8,000 psi dry. With a special additive
to the standard mix directions, Dental Castone can be formulated to be even
stronger and contain good adhesive qualities. Dental castone has a powder/water
ratio of 100 g to 30 cc for the standard packaged instructions. It is a high
quality, high strength dental stone used for dental casts.
As a restoration
product, we can modify the standard white or cream powders to match a wide range
of different body types. It is easy to mix in about 20 seconds and can set in
approximately eight to ten minutes. Some good tools to have are a rubber
flexible mixing bowl and spatula. Allow the leftover Dental Castone to harden in
the flexible bowl and then just squeeze the bowl to break it out. It is
advisable to dump the excess in the trash rather than rinse it down the sink.
Dental Castone is very economical and can be purchased in 25 lbs. or 100
lbs. in white, cream or other colors. One great advantage that Dental Castone
offers is its versatility it can be adapted to a wide range of finished looks.
Depending on when a new additive is mixed into the dry or wet formula, you can
get different effects. For instance, fine powder pigment color(s) can be sifted
into the dry powder prior to the addition of water. The pigment colors then have
a chance to dilute within the Dental Castone to get an overall tone. On the flip
side, if the powder pigment is only sprinkled in, the final cast part will have
various specks of color throughout. This can be of great advantage if you need
to create an earthenware look.
All sorts of additives can be introduced into
the casting of Dental Castone, such as gold leaf powder, gold leaf, luster
powder pigments, and for really unusual results, glow in the dark illuminating
colors. Just think how an object could look normal during the day and glow at
night!
Using the right mold materials can make restoring your collectibles a
safe and successful process.
DiAnna Tindell is a master
restoration specialist and founder of Tindell's Restoration Schools in
Nashville, Tenn. For training, see upcoming class registration for 2006. For
conservation or restoration resources and more details about this article, visit
www.TindellsRestorationSchools.com
or write: P.O. Box 1068, Antioch, TN.
37011-1068, or call 615-941-5354.
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Close-up view of damaged
areas of a
gold frame mirror.
Work in progress with Alginate mold material and Castone casting on a missing
leaf.
Final view of fully restored
large mirror.
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