If you do not have access to commercial slide mounts and do not want to purchase new ones to create your projects, you can also make some from scratch by doing the following. These are a bit more work because it requires measuring and cutting etc but it is a great way to make some when you have very few resources.
On average a slide mount is a square with a horizontal rectangle cut out in the center. The top and bottom are usually larger than the sides. In order to make some of these from scratch, your measurements do not have to be the same as what I have below but they should be fairly consistent in their aspect ratio.
To make your Own Mounts:
1. Cut a square out of Heavy Weight Cardstock or similar material 2 inches by 2 inches
2. To create a window in your mount...
A. For the top border, measure and draw a line straight across from one side of your mount to the other. The line should measure 1/2 inches down from the top edge of the mount.
B. For the bottom border, do the same only this time measuring from the bottom edge of the mount. These measurements and line should be 1/2 inch from the bottom edge of the mount.
3. ) For the side borders Measure and draw a line 1/4 inch from the outer edges all the way across.
4.) See example above. This will create a horizontal window and the cutout guide.
5.) You can round the corners or leave them straight. Real mounts come both ways and it is a personal choice. Since the marks you create are more than likely going to be covered and on the back where they won't show, it really should not matter what you use to mark with. The only time this might present a problem is if you make the marked side the front of your piece and the paper or material you use to cover is too thin and the lines show through.
Note: to round my edges, I use scissors with a slight a curve to the cutting blades which makes it easier to go around edges than straight blades. I find this quicker and easier than trying to use a hand held corner rounder on really heavy stuff. I have a large commercial corner rounder which does cut really really havy stuff but the scissors are still quicker and easier.
Since I just used half of a slide mount when creating my projects, I simply glued a plain piece of cardstock to the back and trimmed around them when I was finished. Adding a separate piece for the back gave me something more solid in the back should I wish to adhere the finished mounts to something else. Now that I have played with some of these, I think I am just a bit addicted and will probably be incorporating then into all kinds of other things in the months to come.
After seeing how I prepared my slide mounts for altering, I hope you will enjoy looking at the actual projects I created with them.