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.

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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