Most of the time I use a commercially made gel plate by GelliArts or Gel Press for my printmaking. Some artists prefer the surface of a homemade gel plate, but it tends to be more delicate and easier to damage. I've gone through phases where I make my own gel plates, usually because I want a specific size or shape.
A few years back I created several gel plates shaped like ornaments for printing on gift bags. I used metal cookie cutters to carefully cut the shapes from a gel plate I made in a Pyrex dish. (I recommend basic cookie-cutter shapes, nothing with too many notches or intricate edges.) You can see the results in the below video.
If you're interested in making a homemade gel plate the recipe I've successfully used many times is adapted from the book Gelli Printing by Suzanne McNeill. Recently, an Instagram follower recommended this recipe at CreativeFabrica.com, which includes isopropyl alcohol. (The alcohol is supposed to help make the plate a bit more durable. I haven't tried it yet, so can't give an opinion on that.)
Permanent Gel Plate
7 – 1 oz. packets of Knox gelatin
1 ½ cups glycerin (I have found this at local pharmacies near first aid supplies)
1 ½ cups boiling water
In a medium bowl mix gelatin into glycerin and stir well. Slowly stir in boiling water, trying not to create too many bubbles. Mix well. Pour into an 8” square Pyrex dish (or similar size Pyrex or nonstick cake pan). Using the edge of a paper towel or piece of newspaper, slowly/gently drag it across the top from one side of the dish to the other to get rid of any air bubbles on the surface. Let it sit for several hours or overnight to set. Once set remove it from the dish. Keep it on a thin sheet of plexiglass or nonstick baking sheet.
It is shelf-stable, so you don’t need to keep it in the fridge. Homemade gel plates are more delicate than commercial ones, but you can re-melt the material if you damage it or just want to change the shape.
To Remelt/pour your homemade plate:
Cut the plate into several pieces about 1-2” wide. Place pieces in a microwavable bowl. Microwave for 2-3 minutes to melt material. If it isn’t quite melted stir and microwave 1-2 minutes more. Once it is in a liquid state again, carefully pour into your Pyrex or other mold. If you want to filter out any tiny paint bits that may have been stuck to the plate, pour through a wire mesh strainer into your Pyrex. Use same steps as above for removing air bubbles and let set overnight.
Happy Gel Printing!