Monday

How to Make Your Own Gesso

I've become quite enamored with Gesso lately. I started using it on my Art Journal pages and discovered that it gives a much better surface for mixed media and keeps the paint from bleeding through the back side of the page. I like the Liquitex brand best, but it gets a bit expensive since I like to slather it on with a credit card pretty thickly.The best price I've found is on Amazon:


Meanwhile, I'm going to research and experiment with making my own gesso to try to save some money.

Historically, gesso was made by mixing calcium carbonate, gypsum, and/or chalk with glue. When applied to wood, it hardens to a bright white and can be used as both a primer and a material for sculpting (like the raising, decorative work on frames). In Renaissance times gesso was used as a ground for tempera paint. On furniture and decorative moldings it can be built up and carved into. Historically, gold leaf was applied to wood that had been coated with a layer of gesso.

Modern gesso follows the same principles, but adds acrylic polymer and chemicals to maintain flexibility.

Calcium Carbonate is a chemical compound (formula CaCO3) that is commonly found in rocks all over the world. It is the main component of seashells, snail shells, pearls and eggshells. It's the active ingredient in agricultural lime & is the primary cause of hard water (it's the hard white stuff that builds up on your bath fixtures). It's also what used in calcium supplements & as an antacid, but taking too much can be hazardous. Easier than grinding up rocks and shells, Plaster of Paris (the result of calcination of gypsum) can be used. Chalk can also be used, but the "real" kind, not the synthetic stuff you buy at a school supply store.

I've found that whatever gesso I use, it's really hard on brushes. I use a really cheap brush that I only use for gesso application, and don't expect it to last very long.

MAKING YOUR OWN GESSO:

There is lots of research on historical methods of making gesso. The product we buy today is a modern version of the original.

METHOD #1: (Plaster of Paris and Glue)


1. Slake your plaster of Paris by mixing together 1 part plaster of Paris and 4 parts water. Let the mixture sit until the plaster settles to the bottom. Then pour off the water and mix again. Repeat this process three times. The plaster reacts with the water. If the mixture gets warmer than when you started, repeat the process. If it appears to be the same temperature as when you started, then your plaster is slaked.


2. Scoop out the plaster of Paris and let it dry completely. Break up any clumps that appear (they may have pockets of moisture). Use a standard kitchen cheese grater and grind it into a fine powder.

3. Mix three parts of the slaked plaster of Paris to 1 part white glue. Add several drops of honey to every tablespoon or so of this mixture. Mix thoroughly and pound out any lumps. Your mixture should have the consistency of pancake batter. The gesso is now ready to use.

4. If you want to color your gesso, mix in a coloring agent. Watercolors, gouache oR acrylics all work well, are fairly inexpensive and easily acquired.

Store your gesso in an airtight container. Add a little water if the gesso becomes too dry. When applying gesso never put your brush directly into the storage container. Always pour out what you need and discard what you don't use. Gesso is easily contaminated and the whole jar can easily become a stinky, rotten mess.

Plaster of Paris is available at most art/craft shops or by mail from Amazon.


METHOD #2 (Dextrin Powder, Plaster and Glue)

1. Mix together 1 cup of dextrin powder (you can order Dextrin / Fine Yellow Powder / 2 Ounces / 100% Pure / Food Grade / SHIPS FAST FROM USA online) and 1 tbsp. of hot (minimum 110 degrees F) water in a mixing bowl. (Yellow dextrin is a glue product, not to be confused with white dextrin which is a food additive that's used as a binder to hold things together. Then there's malto-dextrin which is yet another food additive. But it's yellow dextrin that you want for gesso.)

2. Add 1 tsp. of the dextrin solution and 1 tsp. of standard white craft glue in a separate mixing bowl and stir. Add 1 tbsp. of patching plaster and mix well.  This makes a fairly thick paste, suitable for making raised decorative shapes on frames etc. The paste should be pretty stiff but still viscous enough to pass through a 1/4-inch pastry tip. Scoop the gesso paste in a pastry bag fitted with a 1/4-inch diameter pastry tip. Apply the paste as needed and allow 2 hours for it to dry.

3. To use the gesso for priming canvas or paper for painting or mixed media work, add 1/4 cup of hot water and mix well

Store your gesso in an airtight container. Add a little water if the gesso becomes too dry. When applying gesso never put your brush directly into the storage container. Always pour out what you need and discard what you don't use. Gesso is easily contaminated and the whole jar can easily become a stinky, rotten mess.

METHOD # 3 Chalk & Glue

Follow Method # 1 instructions substituting chalk for the grated plaster. I'm lucky to have a rock-climber in the family, so I can dig into his Black Diamond Loose Chalk 300g BD5504950000ALL1 bag. It's pretty cheap, and easier to use than making plaster, drying it & grating it. Calcium Carbonate - 1 lb. is technically what was used historically. It's a little more than $6 a pound.


METHOD #4 A Modern Adaptation of Cennino Cennini's Recipe
Tom Irizarry has written an interesting article on adapting ancient recipes to modern times can be found here. It also has a good bibliography for further study.

I'll continue to update with resources. Please add comments with your own research and relevant links.









17 comments:

Anonymous said...

What does the honey do? How did you figure this out? This would save me lots of money!

Anonymous said...

Where do you get your Dextrin Powder? How long does the gesso last?

Barbara Jean said...

wow. sounds like a lot of work, but I do know gesso is expensive if you use mush of it.

thanks
barb

Carlyn Clark said...

I get my Dextrin from Amazon. Click on the link and it will take you to what I buy. I don't know how long it will last. I put mine in a plastic bucket that drywall mud comes in and I've had it for almost a year & it's still fine. I keep a smaller container that I use when I'm working so the big container is never open very long.

Anonymous said...

Step 2 in the first method...how long do you let it dry?

Carlyn Clark said...

Tracy Doerr, I crumble a bit in my hand and if it easily crumbles I start grating it. As for how long it takes to dry, I expect that will depend a lot on your climate. I live in relatively dry Southern California and spread it out pretty thinly on an old cookie sheet and it takes anywhere from a few hours (in the heat of summer) to a couple of days (in the winter.) Please share your experience in your climate!

Anonymous said...

Hi All, Jaya here...

For acrylic painting: I use one part whiting, (which is slaked lime, so you can skip all that).
One part water, two parts dulux acrylic interior paint, (ceiling white, or flat white - dulux is extremely flexible),and one part pva glue. Goes on like a dream, grabs everything. Adjust the whiting, (dead cheap for a huge bag from a hardware store), up or down according to your desire.

Anonymous said...

As i am beginner i have 2 questions about canvas painting.
1.can i use canvas which is used for stitching dress or shirt ?
2.can i directly start painting on canvas without gesso /primed?

Unknown said...

Can I use diatomaceous earth in place of plaster?

Carlyn Clark said...

Interesting question Laurie C. I had to google diatomaceous earth to see what it was. I found an interesting article about a Japanese practice of using it in plaster. Here's a quote from the article:

"As concerns continue to grow about indoor air quality and exposure to toxic chemicals in our homes and schools, we've seen a plethora of new wall and floor treatments that eliminate chemicals like formaldehyde and other VOC's (volatile organic compounds). But until now, there hasn't been a surface that absorbs these toxic compounds.

Based on the plaster walls found in centuries-old Japanese temples, the Japanese company Shikoku International has formulated a modern version of the chemical-absorbing wall surface called Eco De Vita. The key ingredient is a high-porosity diatomaceous earth, a soft sedimentary rock made up of fossilized diatoms, a type of prehistoric hard-shelled algae. The cell structure of the fossil allows for an extremely high absorption rate of adjoining minerals (and chemicals). "

So maybe give it a try and see how it goes. And let us know what happens!

Unknown said...

Can i use the on new linen to make a canvas ?

Unknown said...

Did you get an answer. I would also like to size my own linen for a canvas

Carlyn Clark said...

Yes, Karin dogs, this will work on linen.

Unknown said...

Can use ground up tums?

Carlyn Clark said...

I don't have any experience with ground up Tums, but the chalk is so cheap I'm not sure I'd go to the bother. Plus, the chalk is very fine, I'd worry about getting the Tums that fine. Chunky gesso would be my choice!

Anonymous said...

I too would like to know what the honey does in Method # 1 and is there a substitute for it?

Carlyn Clark said...

The honey is added to make the gesso a bit sticky and reduces brittleness so it's more flexible when using on canvas. At least that's what the historical references say. You'll have to experiment to get the ideal proportions for your application. Let me know what you discover!