Building a Diorama - Part #1c - Lightweight Spackling

DAP Fast'N Final Lightweight Spackling:

This is the brand of spackling I got at my local big and small box stores and I am happy with the results.  It does have a number of cautions to be noted.  Right out of the tub I have used a spatula to apply it directly to plaster cloth and foam-core to add texture and then when dry, color with paints, washes and stains.  It did slightly warp the foam-core and I think I will try sealing both sides with KILZ primer next time.

To eliminate white spots when chipped I colored a small batch of spackling by placing about a quarter cup into a small dish, stirred in a few shots of acrylic paint color and added a little water to achieve a thick mud for texture or more water to achieve a soupy mud for painting larger ground areas.  For ground areas I use a tan, for grass - green, for water - blue, for Arizona mountains - purple, for red rocks - red, whatever suits your fancy.  If your fancy changes you can just paint over with another coat to change the season or area.

Creating rock textures and other scenery details is a bit more art than science, it just takes practice.  Try different tools to apply the material, knives, forks, spoons, foam brush, sponges, - they all make slightly different shapes - jab and slice at the material for other effects.

You may also add texture to the spackling by adding ingredients like sawdust, ground up cork or foam, sand something you might find around the house.  As they say, "Try it, you'll like it."   That is why we are building this little diorama, to try new and different materials, ideas, tools, etc.

Building a Diorama - Part #1b - Plaster Cloth

As a model railroader I come from the old school of scenery building, plaster over window screen.  The comments about a large club layout would be "How many houses were denied window screen?"  It was heavy and strong and permanent.  With today's modelers doing more portable and module layouts the weight and cracking of plaster has given way to foam or Plaster Cloth.

Many of you may have had your broken arms or legs placed in a cast made by wrapping a plaster impregnated cloth round and round until it built up enough thickness to immobilize the broken limb.  I am not sure when modelers first took the doctor's material, but, cheapened up, medical logo removed and production moved to China, we now have Plaster Cloth.  Plaster cloth is easily found at most craft stores in rolls, about 8" wide by 15 or 20 feet long and costing about $8.00 to $10.00.

Plaster cloth, when applied in several overlapping layers, produces a thin, strong and lightweight surface suitable for various ground cover textures.  Any supporting material, cardboard strips, wadded-up newspapers, even window screen, is suitable to overlay with plaster cloth.  While wet the surface can be smoothed and worked with a wet finger or bristle paint brush.  NOTE:  All plasters will dry the skin so latex gloves may be advised.

Using Plaster Cloth:
When building my diorama I used twine laced between the foam-core profile boards as the support for my plaster cloth.

 

The next step is to cut the plaster cloth into suitable pieces, approximately 8"x8", briefly dip them in a shallow pan of water and lay them over the twine.  Continue overlapping the cloth pieces, smoothing the edges, until you have two or three layers.  More layers can be applied if needed.  This is how it looked with the twine covered with plaster cloth.

Plaster cloth does have a loose weave pattern that can be worked out by smoothing while wet or covered with one or two coats of latex house paint.  These steps may not be necessary if you will be applying a textured surface.  When dry and after some simple painting I ended up with an early version of my diorama.  Sorry about the poor quality early phone pictures.  The do get better.

Building a Diorama - Part #1a - Foam-Core Board

No one material is innately GOOD or BAD.  ALL materials have ADVANTAGES and DISADVANTAGES.  The secret of success is to find a way to use a material's advantages and be alert to the disadvantages.  I became interested in foam-core after reading a number of biting remarks on several forums about the unsuitability of the material for anything like model railroad layout building.  Yet I had seen pictures of a modeler lifting a foam-core 2'x4' module above his head with one hand.

The Advantages of Using Foam-Core Board:

• Functions much like plywood
• Very light weight
• Greater overall strength than cardboard
• Easily cut with hobby knives
• Easily bonded with various wood/paper glues and hot glue sticks
• Easily painted with hobby acrylics and household latex paints
• Accepts most plaster type materials used by hobbyist

The Disadvantages of Using Foam-Core Board:

• Easily dented
• Not as strong as plywood
• Will warp if painted or wet on only one side
• Some chemicals will dissolve the foam
• Edges are raw and may need to be treated

My engineering background allowed me to see foam-core as just another material that could be fabricated into shapes and structures by using glue instead of rivets and welding.  Here are several photos showing the building of the foam-core layout frame for the diorama.

Tools and Equipment:

• Utility or hobby knives with extra blades
• Cutting board or surface to protect table
• Steel straight edge or carpenters square
• Ruler, tape measure and pencil
• Latex or acrylic paints to seal both surfaces when required
• Adhesives - wood or paper glue, hot glue sticks  (I prefer yellow wood glue-fast gripping)
• Usual collection of hobby tools is helpful

While similar to paper and card stock, foam-core has thickness and the modeler has a tendency to tip the blade when using the straight edge.  Keep the knife vertical and use several strokes to cut the top paper surface and not crush the foam.  Also remember that paper is very hard on blades so replace them often.
Following are some pictures of other uses of foam-core board.

Building a Diorama - Part #1 - New Basic Materials

New Basic Materials:  Part of my reason for building this diorama was to experiment using materials that were new to me.  These new materials were Foam-Core Board, Plaster Cloth and Light Weight Spackling.  In Part #1 I will describe these materials, explain some of their unique characteristics and why I chose to use them.  Below is a picture of the diorama I am building.  A little crude, but a goal for the new modelers learning from it.

Foam-Core Board:  The material I am using is Produced by Elmer's Products, Inc. and is correctly called Foam Board.  This product is a composite material consisting of a foam sheet faced on both sides with a heavy paper creating a very light weight, stiff and quite strong display building material.  It's normally used in booth displays for picture backing and upright display panels.  I make the distinction because I have found similar products in the same area that did not have the heavy paper facings and would not be suitable for this work.  Many in the hobby and craft scene also use the term, foam-core, and I will continue with that term.  Foam-core boards are available in thicknesses from 3/16" to 3/4" and sizes from 20" x 30" to 48" x 96", the larger sizes as special order.  For my project I used the 3/16" thick x 20" x 30" boards, readily available at most hobby and craft stores as well as many art and framing shops for about $2.50 - $3.00 per board.  I found a cheaper source at the dollar type stores for $1.00 per board.

Plaster Cloth:  This material was first used for many years in doctor's offices to wrap broken arms to produce a cast.  Someone in the hobby found the material useful as a strong and lightweight scenery material.  Now the material has moved from the doctor's office to the hobby stores.  Basically, plaster cloth is a loose weave cloth coated with dried plaster and sold in small rolls approximately 8" wide by 15 to 20 feet long.  To use this material you first cut it to small, suitable sizes, briefly dip them in a shallow pan of water and lay over a support structure to give an appropriate shape.  After overlapping several layers of plaster cloth and allowing it to dry you may remove the supporting material and have a scenery base that is rigid and light.  Rolls of plaster cloth cost about $8.00 to $10.00 and may also be found on the internet.


Light Weight Spackling:  This handy product is found in hardware and home improvement stores and we often use it to replace plaster of paris or drywall joint compound.  It is fast drying, flexible, easy to use and may be painted, stained and carved.  The brand I use is DAP Fast'N Final Lightweight Spackling.  It is available in plastic tubs of 16 and 32 fluid ounces.  It is applied with a small putty knife and can be smoothed with a wet finger or paintbrush to produce textures and shapes.  While more expensive than joint compound, the lack of cracking and flexibility justifies the price of $4.00 to $6.00 per small tub and $8.00 to $10.00 for the large.


Caution:  When using any new product be sure to read the instructions and use care until you become familiar with the product.  This project of Building a Diorama is intended for adults and supervised youth.