When your kids try to stump you every Halloween with costume ideas you have to develop some innovative techniques to bring their ideas to reality. This technique can be used to enlarge any small simple object for use as a costume.
Step 1: Creating a Pattern
the first step is to use the original object to create a 1:1 scale pattern.
First, wrap the object tightly in plastic grocery bags. This will allow the finished pattern to release cleanly from the object. Next, tightly wrap the bagged object in packing tape. After a couple of layers of tape you will have a semi-rigid shell on the object.
Now you can take a Sharpie and draw out basic cut lines dividing the shell into manageable pieces. Cut along these lines being sure to label the pieces so you know which go where. Lastly take each piece and make a series of relief cuts in them until the piece lays more or less flat.
Step 2: Enlarging the Pattern (option One)
The next thing you need to do is enlarge the pattern to whatever size your finished object needs to be. there are two ways to do this. This first option is much more labor intensive but doesn't require any specialized equipment.
First, you table all the pattern pieces done on to a piece of cardstock. Then overlay a sheet of 1/4" gridded velum and scan it into a computer. Print out a copy of scanned image to give yourself a gridded pattern.
Now on a large sheet of paper, draw a large grid at whatever scale you need the finished object to be. we needed to enlarge the nesting doll by 4x so we drew a 1" grid. then transfer the points of the small pattern to the larger grid and connect the dots to create your large pattern.
Step 3: Enlarging the Pattern (option Two)
A much less labor intensive option is to take the scanned pattern and enlarge it on the computer in your image editor of choice then print it out at the larger scale either tiled on a regular printer or in one large piece on a large plotter.
I wholeheartedly recommend this option.
Step 4: Cutting and Assembling the Life Size Object
Once you have the large pattern created, trace the pieces onto 1" thick green upholstery foam. This foam is lightweight but rigid enough to hold its shape with a little support.
After cutting, glue the pieces together with a craft glue. I recommend Fabri-Tac as it dries quickly and remains a bit flexible after curing. To hold the pieces together while the glue is drying, pin small strips of ribbon or scrap fabric across the joint.
For the nesting doll we needed a second top piece which we just sort of eyeballed for size as it needed to fit our daughter's head. We could have easily used the same enlarging method but we were in a hurry :)
Because of the size of this piece, we decided it needed a bit of internal support. For this we used some old hula hoops cut to the correct diameter and glued into place.
Step 5: Finishing the Piece
Once the foam shell was complete we traced onto it the paint lines from the original doll. Then we laid tracing paper over the lines to get a paper pattern of the major components.
To begin covering the shell we used the same pattern used to make the shell to cut pieces of colored felt which was then fit and glued in place onto the green foam.
The details were cut from other felt and outlined in black squeezy paint before glueing to the shell as well.
The face was painted onto latch hook screen so our daughter would be able to see through it.