(Dateline: April 98th, 2010 ;) )
My dad and I recently learned about letterboxing. It's an informal treasure-hunt sort of game, similar to geocaching, that began with a gentleman's calling card left tucked into a bottle near a remote English pond in 1854. In the modern version of letterboxing, one follows clues left on a website to find a secret stash containing a rubber stamp and a logbook. The adventurer brings their own signature stamp and logbook along, stamps an image from their signature stamp into the letterbox's book, and takes an image of the letterbox's stamp away in their own logbook.
While there's no rule against using a store-bought stamp, either for your signature or for the letterbox, it's so much more personal to create your own design. Indeed, the vast majority of letterboxers use stamps of their own design. They may have the stamps custom made by a stationery company, or carve them themselves from rubber erasers. Being somewhat uncertain of my ablility to carve a rubber eraser, and displeased with the small size of the erasers I found, I went looking for an alternative material. I found it in craft foam sheets.
You will need:
One sheet of adhesive-backed craft foam
One sheet of 6 mm thick craft foam
A craft knife
A cutting surface
A stamp pad with a raised surface, or a watercolor pen
Your stamp design
Your design can be quite detailed, but you should probably try not to get too fancy with your first attempt. You can hand draw your design or use a graphics program to create one. Consider the size of your image carefully. It should be small enough to fit on a small logbook page, but large enough to be easy to cut out of the foam. I chose a daffodil design that I use elsewhere as well, and my dad created a simple radio tower design, alluding to his ham radio hobby. We decided that three inches in the largest dimension of our designs would likely fit well in most logbooks.
As you work with the adhesive-backed foam sheet, be careful not to press your fingernails into the foam. It will take impressions from your nails rather easily, and your stamped design may have small crescent-shaped voids as a result.
I found that carbon paper refused to transfer to the foam, so I cut the designs out of their paper print-outs with the craft knife, then used them as stencils to apply the design to the foam. My daffodil design was already created in a stencil-like negative image, with the pieces of the flower cut from the background. With the finished stamp, the background would be printed, while the flower remained the white of the paper. My dad's radio tower, however, was a positive image with crossbars that needed careful handling in cutting the transfer stencil. I left thin bands of paper between the crossbars and the uprights on the paper stencil, to hold the design together. I would later cut through these lines when cutting the design from the foam sheet.
Place the stencil on top of the adhesive-backed foam and ink through the stencil with the stamp pad. (If your design has letters or any other element that requires a certain direction, make sure to put your stencil down backwards.) I had a little trouble getting all the smaller parts of the pattern inked, and by the time I did, there was a good bit of ink bleeding through the paper onto the foam. I think a smaller, dauber-type ink pad or a water color pen would have worked better, but I didn't have either of those, and I was able to see the design clearly enough on the foam to cut the design out.
With your craft knife, cut the design out of the foam. There are a couple things to which to pay attention as you cut. The first is that you don't undercut the edge of the stamp. It's best to angle the blade of your craft knife away from the piece at the point of the blade, so as to ensure adequate support to the edge of the foam. The other is that you either start at one side of the pattern and work across, or start at the center and work your way out. This is so that the piece you're cutting always has as much support from the surrounding foam as possible. On my daffodil, if I had cut all the petals first, then cut the trumpet out, I would likely have broken through the lines as the lack of support allowed the foam to stretch and flex.
If your image has several separate pieces, and their exact placement on the stamp is important, don't just cut the pieces out willy-nilly. With my dad's radio tower, I chose to cut the tower out first, as the anchor of the design. I stripped the paper backing off of the adhesive back of the tower, and placed it on the 6 mm thick foam sheet. Then, one by one, I cut a lightning bolt, but did not remove it from the surrounding foam. Instead, I removed the paper backing from just the lightning bolt, fitted the surrounding foam around the tower on the 6 mm thick foam sheet, pressed the lightning bolt down, then removed the surrounding foam from the now-adhered bolt.
Once you have all the pieces of your design adhered to the 6 mm thick foam backing, cut the stamp from the rest of the sheet. Cut off any excess backing that isn't supporting the image. Doing this will help prevent accidental stamping of the edges of the backing. Ink your stamp and make a test imprint on a piece of paper. If you use watercolor pens, you can color different parts of the stamp different colors for a multicolor image.
Congratulations! You've made your very own personalized stamp. Now, go gently clean it with water and an old soft toothbrush. The ink will never completely dry on the foam, so cleaning it off will reduce accidental stamping on your clothes and furniture, as well as prevent a buildup of residue that can reduce the quality of your impressions.
Not only are craft foam stamps easy and fun to make, they are incredibly cheap! Having a 3" x 3" custom stamp made professionally costs about $25. Both the self adhesive foam and the 6 mm thick foam were a mere 99 cents per sheet. I made two stamps, and have enough foam left over for at least another four stamps of the same size. This means that each stamp used about 30 cents worth of foam. That's what I call thrifty!
For more information on letterboxing, visit the Wikipedia entry at http://en.wikipedia.org/wiki/Letterboxing .