Obviously they firstly needed to be very light, reasonably robust and BIG. Anyway, here's the image I was given:
So the materials used:
Polyurethane packing foam. This is very light, easy to cut with a craft knife or box cutter. It's soft enough to be reasonably comfortable for the model and most importantly it is reasonably stiff. It will be used for the main 'spars', so if you are using some other material, the test is simple. Cut a four foot length 1" square, hold it by one end and see how much the other end droops. It it only droops by one or two inches then it should be fine for this job.
Black Organza Voile. A very lightweight 'shimmery' mesh fabric for the membranes. You could use any one of the hundreds of colours available.
Liquid Latex. Used as a strengthening skin for part of the spars and to glue the fabric to the spars
General purpose adhesive. Bostik, UHU or a similar adhesive that can be used as a contact cement.
Paint. I used artists acrylic inks for this job which were airbrushed on, but any sort of hobby acrylics would do just as well.
Before continuing with the next set of steps I must apologize for my state of undress in some of the images. It was the middle of a heatwave and unbearably hot in the workshop!
Step 1: Constructing the Spars
Using as much of the width as I could I cut two curved 'bone' shapes about 2 1/2 feet long to form the two upright curved spars.
I then cut two four foot curved and tapered lengths to form the main outer spars. These were joined to the uprights using general purpose adhesive using the impact method and pinned through with cocktail sticks.
Once the two main structures were glued I cut four smaller lengths of foam for the inner spars. Again these were cemented into place and pinned with cocktail sticks.
The two assemblies were then given 24 hours to fully cure.
Step 2: Adding the Horns
These were then sanded using a Dremel (or similar rotary tool) with a rough sanding drum installed.
The horns were then glued and pinned in place and left to dry overnight.
Once everything had fully set, the Dremel was used to sand all the cut edges and round off the corners. This took all day before I was satisfied with the results.
The main wing structure is now completed.
Step 3: Adding the Membranes
A layer of liquid latex was applied to all the surfaces where the fabric would be added. This layer was left to fully cure.
Once the latex was dry the sheet of organza was laid over the frame. At this stage the latex will not stick the fabric but it has enough 'tack' that the lightweight material will stay in place and flat while we cement it.
Another layer of latex was painted onto the organza allowing it to flow through the mesh and onto the layer beneath. Once this layer has cured it will bond the fibres of the fabric to the layer and the structure beneath. This will form a very strong bond.
Once it had all fully cured, the excess organza was trimmed using a scalpel, an X-Acto or craft knife would do the job just fine as long as it is very sharp. The bottoms of the organza were trimmed to a set of 'U' shapes with a small pair of scissors.
Step 4: Stregthening and Sculpting
I made a pair of stiffeners from some show card (it's about 1mm thick) and glued them to the backs of the main uprights. This stopped any flexing.
I cut four figure of eight pieces of foam and then sculpted them using the Dremel to form the two end 'knuckles' at the joint of the main spar. These were cemented in place using general purpose glue. I cut two strips of soft foam and glued them around the base of each horn and again did a little sculpting with the Dremel.
The base of the horns were sculpted using a hot iron to form some indentations.
The main spar, the jointing area and the horns were then given two coats of latex to strengthen and blend the sculpting.
In the second image the latex is still wet in places and the card stiffener can be clearly seen.
The long spar and the two membrane support spars were left 'raw' to save some weight. Once it was all dry the wings were suspended from the main spar and the membranes were given four coats of dilute (10%) PVA using a kitchen spray bottle. Each coat was allowed to dry in between. This stiffens the organza considerably and helps the wings hold their shape once fitted to a model.
Step 5: Painting and Finishing
I used an airbrush but you could do a good job using brush and sponge.
I started with an undercoat of dark brown (burnt umber) artists acrylic ink. Once dry this was over sprayed on the main spar, knuckle joints and horns using opaque white.
Finally some black shadows were added and finally some white highlights using a fine brush.
You can see how large the wings are. They will be fitted using two large attachment pads made of 6 layers of latex. I will update this 'ible once the shoot takes place.
The wings each weigh 130gm or 4 1/4 ounces so the pad will need to be large enough to support the wings and prevent them from rotating and coming off the models shoulders.
Step 6: The Completed Wings Fitted
Here are the wings fitted to a model for a body paint event in The Netherlands. Came third in the SFX category so I was pleased.