Step 1: Determine Measurements and Print Out an Offset for the Template
The formula for the offset is (bushing size - router bit size) / 2 = offset. The bushing I used is .4375". The bit was .25". The offset is .09375" (fraction is 3/32").
In Photoshop open or make a two tone graphic. This graphic of a hop is about as complex as you can get. Just remember that the router bushing is almost a 1/2" wide and the blade is a 1/4". Any tight inside corners might start to disappear when cut. Look at the hop stem in the test cut for instance.
-Note the resolution of your graphic. (From the menu Edit>Image size. There is field that tells resolution)
-Multiply resolution by the offset. Mine is 72 dpi x .09375 = 6.75. This is your pixel offset.
-With this graphic open and sized to the correct size you, select the white space. From the menu click Select>Modify>Expand. Put your "pixel offset number" in the dialog that comes up. It will expand the selected area. You can either fill the selected area or the inverse selected area with another color as I did here with red. Print this out.
Step 2: Glue It!
Step 3: Cut It! (the Template, That Is)
Drill a few holes and cut out most of the way with a jig saw. A scroll saw would come i handy here but I don't have one. I had to resort to carefully cutting freehand it with a small bit on a router table (not recommended for a first time) and file to finish it up(recommended). The important thing is that the edges are uniform. When finished the paper can come up or carefully sanded off.
Step 4: Cut the Shape With a Router.
It is highly recommended to try a new shape out on a scrap. It is possible that the shape needs to be altered.
Also when starting a cut that will go all the way through, use a scrap underneath. This may seem obvious but if you forget you will have to unclamp the template halfway through. It is very hard to get it to realign.
Here are some things to keep in mind if you are new to using a router.
The best method for cutting is very little by very little. Try to keep the plunge passes in 1/8" increments. Clean out the dust after each pass. The accumulated sawdust buildup from too deep of a plunge will burn junk onto the router bit. Router bits are pretty useless burned up and cleaning them up is a real pain. Also, pushing the router the wrong direction can cause the bit can get hung up and lunge in one direction. This is sometimes called climb. To avoid climbing keep your cuts shallow, cut clockwise when cutting on the inside of the shape. This means you are pushing in the same direction that the blade is cutting and against the force of any kickback. If you were cutting on the outside of a piece of wood you would work counter-clockwise. If this is confusing, just look at the direction the blade will be cutting into the wood and think of it as pushing a carving knife around the edge.
A good type of blade to use for cutting deep shapes is a spiral up-cut. These are nice because the slicing action pulls the router onto the wood and they can typically be found in longer lengths than other straight bits.