How to Make a Stencil for You Hot Wire Foam Cutter
If youíve ever tried cutting straight lines in Styrofoam with a hot wire foam cutter or HWFC, you may have noticed it is nearly impossible without a guide of some kind. Thatís where stencils come in. With a well made stencil, you will find it much easier to cut a wide variety of shapes to a high degree of accuracy that fit together very well.
I use poster board for my stencils. Itís cheap and readily available at most craft, grocery and department stores, itís easy to cut, and itís highly durable and resistant to the heat of the HWFC.
For tools, you need:
One roll of inch wide masking tape, white is cheaper than blue and does the job just as well
One utility knife with a sharp blade, preferably the disposable kind. A dull knife can ruin your stencil or cause a serious accident and cut you. Just in case, make sure you have a good first aid kit around so you can patch yourself up, and always watch your hands when you cut!!
A good cutting surface. I use 1/8 inch MDF aka Luane aka Masonite. Itís cheap and comes in a variety of thicknesses and sizes. Itís firm, so you can use it anywhere if you donít have a large flat table, and it protects anything you lay it on. It also sticks to tape very well, which is important for this project. Did I mention itís cheap and disposable?
Easy Square or Steel Ruler (no plastic or wood rulers!!) at your first opportunity, get an Easy Square! Mine cost about $10 and Iíve been using it for years. Itís made of thick durable plastic and has a Ĺ inch grid printed on it. Itís super accurate and makes layouts and cutting jobs go QUICK. If you canít find one, use a steel ruler.
Super fine marker (Sharpie) or pencil to trace your pattern
HWFC Hot Wire Foam Cutter - Games Workshop has a battery powered HWFC for less than $20. It takes 2 D cell batteries. Get some spare wires while youíre at it, you never know when the wire will break! There are 12 volt varieties available, but Iíve only used the one stated above. Read the manual included with the HWFC for instructions on its use.
Finally, you will need the foam! Home Depot sells ĹĒ, ĺĒ, 1Ē, and 2Ē thick 4íx 8í sheets in my area. Some brands include Owens Corning, DOW Jones and Greenguard. The white stuff can work, but its crumbly texture can be hard to work with for this project. Check with your local hardware store and see what they have.
Letís get started!! Donít worry if you mess up the first one, it takes practice and experience to figure out the best methods. I made a lot of bad stencils before I made my first good one!
Before you do anything, youíll need a design or pattern for your stencil. Hereís one I drew in Paint:
Notice the lines in the middle are 9/16Ē apart. The Ĺ inch foam I bought at Home Depot actually measures 9/16 inches on a side! You may want to measure the thickness of the foam youíre going to cut before making your stencil. This can make a world of a difference.
Youíll want to tape your poster board to the cutting surface. Do this before you even draw the pattern or layout. Youíll find everything goes a lot smoother when you tape the work down first.
Next, weíll draw a perimeter for our stencil:
You want the perimeter of your stencil to be spaced at least Ĺ inches around your pattern to the stencil will be durable and will fold relatively straight when you wrap it around the foam youíre going to cut.
Next, we draw our pattern:
For my pattern, I left Ĺ inch on the sides that fold around the foamís edge and 1Ē on the side Iíll hold with my fingers. This ensures the hot wire will not bump into my fingers when I cut the foam, so my cut will run straight and smooth, and I wonít get burned! Louch!!
On to the cutting!!
Cut the perimeter first using the utility knife. Donít worry about cutting past the outline. After you cut the perimeter, remove the stencil and lay it flat on the cutting surface. At this point, you can tape the stencil to the surface and cut out the pattern. DONíT CUT THE SEAMS! I know the picture says so. If you did cut the seams or cut outside of the corners of your pattern, patch it up with masking tape.
Finally, Iíll tell you what I meant by ďCut the seams lastĒ. That means you place your easy square or ruler along the seams and LIGHTLY drag the knife over them. This will score lines into the seams and make them bend sharply around the edges of the foam.
Next, peel your stencil off the cutting surface and LEAVE THE TAPE ON! Fold it around the edges of your stencil to reinforce it. Look here:
See? If you add tape around the inside edges of the stencil, the HWFC wire wil glide smoothly along the corners of your pattern without damaging the cardboard. Your stencil will wear out and fray eventually, just add more tape or cut out a new stencil. These things do happen. You might even come up with a better stencil design as you make more!
Now letís see our new stencil in action:
Get creative and try cutting out as many shapes as you can with your new stencil. Practice makes perfect! Try making different stencils and experiment.
Hereís another project idea to get your juices flowing:
Wanna know how I made this? With a lot of practice! Thatís how! Get going!