Spinning Wheel, Spinning True

Spinning Wheel, Spinning True


Fabricating Parts with Amazing Molds and Casting Resin


Published: 2/8/2015
By: Jerome Vernon
About the Author: Jerome Vernon is a software developer/project manager and an avid antiques enthusiast. When Jerome’s not busy creating business related software products for his clients he’s restoring antiques and writing articles for Restoration News.
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Spinning Wheel, Spinning True
Fabricating Parts with Amazing Molds

A while back, I purchased this mid 1880's spinning wheel (shown left) with the intention that my wife would use it as a decorative piece in her sewing/crafts room. Although no longer in widespread use since the early 1800's, it seems the spinning wheel remains etched in the collective thoughts of both young and old.  Spinning (flax) wheels first appeared in Asia around the 11th century and became commonplace in the homes of Europe during the 13th century. The more decorative pieces with improved functionality such as shown here were produced through Europe but primarily in Germany. The spinning jenny and spinning frame, displaced the spinning wheel during the Industrial Revolution and by the mid 1800’s, apart from the purist’s, most were relinquished to the attic, basement or rubbish heap. The title of this article is derived from a popular song. In 1969, the band Blood, Sweat & Tears, was nominated for three Grammy Awards for its song 'Spinning Wheel'. The lead vocalist, David Clayton-Thomas was quoted "it was my way of saying, "Don't get too caught up, because everything comes full-circle." In this article, you will see how I bring this old spinning wheel full-circle with a few simple repairs.

Ok, enough about spinning wheels, this article is really about fabricating those broken or lost decorative elements of any item using an easy and low-cost method. For me, it’s quite common to come across antiques with either lost or destroyed embossed appliques, finials, capitals/crowns, ornamental hardware and broken chunks of gesso that make an otherwise simple project complex.  

The materials to be demonstrated here are manufactured by Alumilite Corporation/Amazing Crafting Products of Kalamazoo, Michigan. More specifically the companies 'Amazing Mold Putty and Casting Resin' products will be used to recreate some missing carved-bone embellishments on the spinning wheel, sections of gesso on a picture frame and, a decorative section of gesso-over-wood on another frame.
You will see how to turn once complicated repairs into a quick and simple process. Best yet, you will find the cost-effective Amazing Mold Putty and Casting Resin products available locally at many craft and hobby outlets.


Molds and Castings

Mold making and casting is a series of manufacturing procedures utilized for the production of 3-dimenional objects. The basic procedure goes back to the Bronze Age with some of the earliest examples from Mesopotamia dating to around 3000 BCE.

Molds are made from a host of materials including wood, clay, metal and, more recently, silicone rubber. A liquefied material is either poured or injected (through some manner) into the vacant mold cavity and once solidified; the resulting casted replica object is then removed. Subsequent procedures applied to the cast may include the removal of unwanted material(s), machining, polishing and/or applying a finish. 

Over recent years, silicone rubber molds and epoxy casting resins have been introduced by a number of manufacturers and are now widely available. Silicon rubber molds can be made soft and pliable (from pourable liquid) or rather stiff and rigid (from formable putty). These modern materials have rapidly gained in popularity because they are relatively safe, easy to use and deliver fast, almost instant replicas of the original object.


Process Steps

Creating  Soft Silicon Rubber Molds

Several of the carved-bone decorative embellishments are missing from the antique spinning wheel. Thankfully, the remaining embellishments have survived the wrath-of-time and several will be used to create rubber molds of the originals.

Acetone is sparingly used to soften the old glue so the embellishment can be easily removed without breakage. Once removed, coffee stir sticks are temporally attached using cyanoacrylate adhesive to facilitate suspending within a paper cup.

Shown here, the paper cups are used as mold boxes. The carved-bone masters are suspended approximately .5 cm (~1/4 inch) from the bottom of the cups.

The soft silicon rubber mold material is a two-part mix. The hardener is blended to silicon rubber by a weight-mix-ratio of 10:1. Care is taken to NOT introduce bubbles so; the mix is gently stirred (not folded) until fully blended. The blended material is then poured into the cups (mold boxes), fully submersing the carved-bone parts. In this case, the mold boxes are set aside to cure ~4 hours. Dependent on mass and temperature, the actual cure time for Amazing Mold Rubber is 2-4 hours.

After the silicon rubber molds have cured, they are removed from the paper cups. Being silicon, which nothing sticks to, they slip out of the paper cup mold boxes quite easily. Next, the carved-bone parts (masters) are removed from the molds using a sharp razor blade. Being careful not to damage the parts, the molds are sliced just enough to remove the parts but not so much to sever or cut completely through the molds. Usually a small slice and a gentle pull is enough to remove the originals. Notice that the coffee stir sticks have left a convenient opening (casting resin port) at the top of the mold.
 
To make the replica parts, a two-part casting resin is mixed (50/50 ratio). The casting resin is watery thin and pours into and fills the mold cavity completely. Note that masking tape can be used to mechanically block any cracks or holes in the mold where the watery thin resin would otherwise leak. The replica parts (castings) are allowed to cure for about two hours then removed from the mold. Excess material can then be easily cut away (trimmed) using a hobby knife with further refinements done using files and/or other abrasives prior to painting/finishing to match the original.


Gesso Repairs Using Rubber Mold Putty

Sometimes the original object requiring replication cannot be detached. The object may be part-of another object or adhered-to a substrate. For example, a section of fragile gesso on a picture frame would not survive removal/replacement procedures. In these cases, an alternative to the soft silicon (pourable) rubber molds as described in the previous section is needed.

Firm silicon rubber molds can be created using thick two-part putty mixture which is pressed both into and around 3-dimenional structures. Once cured, the firm silicon putty is then pulled away; retaining the exact dimensional characteristics of the original piece.

To prepare the molding putty, using latex gloves, equal parts (50/50 by volume or weight) of both part A and part B compounds are mixed by hand kneading.  Care is taken to avoid introducing bubbles into the mix which is eventually rolled between hands to eliminate folds. Depending on batch size, the optimal mixing time is 15 seconds. Depending on temperature and mass, the open working time is approximately 3 minutes before the material begins to harden.  To extend working time un-mixed mold putty can be stored or pre-cooled in a refrigerator. Demold (cure) time, being dependent on temperature and mass, is approximately 15-20 minutes (30-40 minutes if pre-cooled).  Prior to curing the consistency of the mix is similar to Play-Doh. Although more pliable, when fully cured the mold putty consistency is similar a soft gum eraser.

After mixing, the un-cured putty is pressed firmly into the original. While forming, ensure ample thickness of the putty to achieve a firm mold thus a more accurate cast. After the mold putty cures, in this case 15-20 minutes, it is gently pulled from the original. Some bending and maneuvering of the material may be needed for originals with deep reliefs/crevasses. As can be seen in photo shown left, a highly accurate representation of the original gesso pattern is reproduced into the cured putty.

The casting resin to be poured into the mold cavity is watery thin. Shown left, the ends of the mold have been cut square and placed firmly into a containment housing constructed of heavy card-stock and cyanoacrylate adhesive.  The two-part casting resin is mixed (50/50 ratio), poured into the mold and allowed to cure for about two hours then, the casting is removed from the mold. Excess material was cut away (trimmed) using a hobby knife. The castings were then, aligned, cut and glued in place using cyanoacrylate adhesive. Margins and transitions were filled and shaped using white modelers putty prior to finishing.


Creating Structural Parts Using Rubber Molds

In this example, I will replace a lost capitol section of gesso-over-wood on another picture frame using Amazing Mold Putty.

Using latex gloves the molding putty is prepared by mixing equal parts (50/50 by volume or weight) of both part A and part B as described in the previous section. Pictured left, the mixed mold putty is pressed (squished) around the original (front, back and right-hand side) and left to cure for ~2 hours. After releasing the mold from the original (master), the mold is further prepared by cutting the left-hand side square and wrapping with cellophane tape. Although the tape will not adhere directly to the silicone-based putty, it is wrapped tightly, forming a dam to retain the watery casting resin within the mold.
 
The two-part casting resin is mixed (50/50 ratio), poured into the mold and allowed to cure for about two hours. Next, the casting is removed from the mold. Excess material was cut away (trimmed) using a hobby knife and razor saw. The casting is then glued in place using cyanoacrylate adhesive. Margins and transitions surrounding the cast were filled using white modelers putty prior to finishing.

Conclusion
I've been using Amazing mold rubber, putty and casting resins for a while now and have found the products indispensable for replicating long-lost or destroyed decorative embellishments on a wide variety of furnishings. For more robust needs such as hardware, appliance, machinery and automotive applications; Amazing Crafting Products parent company, Alumilite Corporation offers a wide array resins, hardeners, metalized/ceramic additives and colorants.  For example, Alumilite’s website includes demonstrations of a vintage automobile steering wheel and red/yellow (dyed) clear tail light lens, both created using the company’s mold making and casting products. In addition, Alumilite Corporations high tech engineering division provides 3D scanning, printing, modeling, and structural/thermo-flow analysis as well as fabrication services.

Among restorers, I have found varying opinions regarding the use of mold making and casting materials. Some contest that the replicated components are not actually the original (real) bone, wood or gesso material. This is true however; you will also find that leading museums worldwide commonly utilize the exact mold making, casting materials and methods described in this article to reproduce long-lost components in paleontological, early civilization and historic displays. Without prior knowledge, onlookers believe they are observing the actual artifact. For antique restoration, the process of combining resin-based castings with a range of artistic paint techniques (for example: Trompe-l'oeil & Faux bois) provide highly realistic replicas of original elements quickly, easily and without 'Blood Sweat & Tears'.

Disclosure
Restoration News accepted no monitory award, support or payment from Alumilite Corporation for the development and publication of this article and its content. The content, usage guidance and, general opinions regarding all products mentioned here are the sole opinions of the Restoration News staff; as determined by their independent interpretation, analysis and testing.  In addition, Restoration News assumes sole responsibility for all content contained in this article as defined by Restoration News limitation of liability and website disclaimers.

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References
  
Amazing Crafting Products
   Amazing Crafting Products - Retailers
  
Alumilite Corporation
   Alumilite Corporation - Main Website
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