Foam Techniques Molding
Learn the advantages of molding foam for your next model!
By David Johnson PHOTOGRAPHY: DAVID JOHNSON & THAYER SYME
Author David Johnson is well known for his giant scale WWI competition models and the many accolades they have received. His efforts have earned him repeated recognition at top tier events such as the AMA Nation- als, Scale Masters Championships and Top Gun. His passion for modeling extends across all sizes though, as evidenced in this article demonstrating foam molding tech- niques he has refined with fellow scale en- thusiast Sean Cassidy.
Working together on numerous smaller projects over the last several years, Johnson and Cassidy have developed a set of innova- tive techniques for molding Depron that al- low a level of surface detail rarely seen on much larger models. These techniques also brought mastery of the compound curves so commonly seen in fuselages, cowls and wheel pants. Combined with more traditional mod- eling techniques, these two have brought ex-
quisite detail to micro indoor models without undue weight gain. I encourage you to resist the intimidation that could so easily come from viewing these models, and instead take inspiration for your own projects. The basic techniques demonstrated are readily achievable to any- one with the ability to carve a block of wood and turn on an oven. With a little practice, you should soon be producing component pieces much lighter and more durable than traditional wood structures allow.—Ed.
D
epron foam sheet is a versatile material which can be easily molded into simple and compound curved shapes. You’ll find it useful for building lightweight yet strong indoor scale flyers, micro planes, and 3D planes. Foam isn’t limited to boxy fuselage shapes anymore. You also don’t have to fly flat air-
foils just because you choose to use light- weight sheet foam. Molding foam sheet is a fairly simple process, and straightforward if you follow a few simple guidelines and learn the techniques.
If you have worked with MonoKote before, you’ll recognize some of the same skills and principles in action. If you haven’t, don’t worry. It takes only a little bit of patience to develop the skills required to mold sheet foam—and the courage to try.
Making molds and forms In order to mold foam sheet, you’ll need some kind of a rigid form that will force the foam into the position you want while it’s be- ing heated. Molds and forms can be built up using ribs and sheeting or they can be carved and sanded from balsa block. Typically, I use a solid carved block for my fuse halves and a built-up wood mold for my wings.
The more you look at Cassidy’s Bristol F.2 the more you see (above). Note the structural detail of the wing (at right) highlighted by careful airbrushing, weathering, and some full-scale dust. The texture was all incorporated into the mold and pressure formed while shaping the wing.
44 MAY 2014
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