Gesso Recipe

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Woodworks by John

Woodworks by John

CGF II, Certified Grumble Framer Level 2
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Jul 4, 2000
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North Las Vegas, NV
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Retired, work from home shop
Okay, I love opening a can of worms on the forum so will give this a try. Would any of you that do gilding care to share your recipe for the gesso using distilled water, rabbit skin glue, and gesso powder? I've been looking them up and there seems to be a wide variation of them and they're shrouded in mystery like some ancient ritual! I'm after a recipe that makes just enough gesso for a 16 x 20 frame or there about. Just a note though, if I don't respond quickly I'm still having issues trying to figure out why I'm not getting my notifications -- that's shrouded in modern hebejebe!
 
John,

Here's a simple recipe:

20 ounces water, by volume.
40 grams glue, by weight, though this may vary with each batch of glue, due to variance in Bloom strength.
2-3 regular size tuna cans of whiting.

Optional: linseed oil, alcohol, salt. Oil adds some flexibility and can be added by pouring a small amount in as the mix is stirred. I use an electric hand mixer if I'm adding oil. Alcohol helps in "wetting" the glue, and is a mild preservative. Salt is the simplest additive to slow the gelling of hide glues.

Soak the glue in the water til soft, zap it in the microwave til it's 150-160 degrees, add whiting, stir, let cool, then reheat. This helps with pinholes, and a smooth mixture.

Other options: Secret incantations, mindless ritual, and pointless superstition, and of course, the costliest of ingredients. :smiley:
 
Have the recipes really been that different? I find that they all wind up being pretty much the same ratios water/glue/whiting. Just pick the easiest one and go with it.

I use Marty Horowitz's for new work, primarily because it is a "measure and mix" recipe, so good, easy process for the larger quantity. The other one I use often differs only in the sequence of mixing, and I just find it easier when I want a small amount and/or a thicker gesso.

There are only three ingredients required in almost all of these, and I have found that the sky doesn't fall if you skip the optional stuff.

Joseph
 
Water glass of water, good hand-full of glue and about a coffee cup of whiting.

soak glue over night...... mic or double boiler... (I like the boiler because it produces more of the wonderful smell) until very warm but not boiling. Slowly stir in whiting until it reaches the consistency you want.

and here is the important part, and why recipes vary.

  • More whiting/less glue = easier to sand, but more delicate
  • More glue/less whiting = tougher shell but not easy to sand
  • More water = thinner layer that shows off carving better
  • Thicker viscosity=builds layer faster for repare
  • A table spoon of urine gives it flexibility and endurance against the elements as well as bugs and assistants won't eat it.
  • Warm/hot gesso dries faster, but also sands smoother
  • cooler-warm gesso gives you longer time to sgraffito or incise, but longer before you can sand for final clay.
clay is even a wilder set of parameters for the clay/glue mix... I just like a hand-full of each. Mix with water until you get consistency perfect.... then spit in the mix a couple of times.... and keep mixing over the boiler. Let stand in the boiler for a couple of hours, with the occasional slow stir. (that should get the bubbles out.)
Apply clay slowly and with a mop.
 
Ah hah, just as I suspected -- a plethora of ways and methods. Lucky for me I haven't started to use Flomax yet so at least one of the ingredients is easy to find! Would I be correct in thinking it really isn't all that critical and just follow the guidelines Baer suggests? I do tend to over think things, even to the point of pre-worrying!
 
BTW John.... if your sawdust is fine enough, and you substitute sawdust for the whiting.... you can make it into a mold-able putty to press into mold for details.... kind of like a poor man's compo. Only, this can also be carved a bit.
 
Dang Baer, you know a lot of stuff and appreciate you passing it all on. I guess my main question on the gesso is the amount of grams of RSG to distilled water for the glue process. After that I see that it's equal parts of the RSG mixture/distilled water/and gesso. What say you?
 
Man, you were so close...... then you decided to buy some trouble.. just because it was on sale or something.

Contents:

RSG crystals
Water
Whiting.

It's like baking.... you can't just throw everything in at once . . .

Start with the water... pour in the glue crystals and let sit over night.

The next day.... Slowly heat, stirring occasionally until all has dissolved. Heat again if you're using a mic.. Slowly add whiting (about a table spoon at a time)while constantly stirring slowly.... Don't add any more, until all of what you added has dissolved into the mix.
This is no time to get in a hurry.

I like to mix mine in the morning, and let it just kind of simmer there while I have lunch.... Paint on with a mop brush.
 
IF, you are in a hurry......

1 oz of white glue in 1 cup of water.....

heat a bit.... and add whiting until desired consistency.... works great.... but sands hard.
 
I'm surprised at the 150-160 degrees! Good temp for mashing malted barley but I was taught & everything I can think of having read tells me that the strength of rsg seriously degrades over 110 or so. You really heat it that high Bron? I really like the addition of linseed oil & have found the new modified water soluable types, like Windsor Newton makes, really mix well without the seperation you tend to get with regular linseed oil. Otherwise I'd say most of the proportions I've seen are fairly similar. I think the finer variations are something you work out as you go along. Has a lot to do with whether you want your gesso softer or harder & climate I think. You need less glue in drier conditions & more in high humidity.
 
Great catch Terry...... that temp just slid right by me....

When I say "hot-warm", I'm talking a hot tub that is too freaking hot to sit in for 5 minutes..... not a par-boil.

I just went an looked at my hot plate.... its half a freckle past the 2 out of 12.

RSG will completely dissolve in a jar of water that is set out in the sun. Usually by mid afternoon on a good warm day. So heat is a marginal thing.
 
Terry,

You can't believe everything you hear. :smiley:

The difference between "hide" glue and "rabbit skin" glue is one of nomenclature, especially in the states, and gram strength. Most of the RSG is in the 350-450 gram strength range, while glue for general wood working is in the 130-250 range; batches will vary, and most of it is of cattle origin. We eat a lot more beef than rabbit burgers.

Generally accepted temperature is in the 140-160 range, with the admonition to not boil the glue, though if you google this, temps are all over the map. Since I spray gesso after the first coat, I like it hot.

Most of my info came from reading older books about hide glues, artists manuals, wood working treatises, and finally, some conversations with Eugene Thordahl, former President of Peter Cooper Corp., manufacturers of protein glues, who started as a chemist for them. I trust his information.
 
Baer,

Temperature is a factor in workability more than anything else. I've seen no problems from doing gesso at 150-160F, and likewise, brush coats are often "cool", though brushability is tough when the stuff is gelling.

In terms of problems, mine are usually marking and cutting 24, when the order clearly states 25, and it's always one inch. :shrug:

Terry, I'll have to look at the W&N oils, though a slow drip of oil into the gesso mix using an electric blender works well.
 
Gesso (Marty Horowitz):
Make a rabbit skin glue using 20 grams glue/8 ounces water. When liquefied, add 1.5 cups whiting, stirring gently to mix and absorb liquid. You can add ½ teaspoon boiled linseed oil and tablespoon denatured alcohol (let these sit on top). Let it sit an hour (keeping it warm), then stir and strain.

I have had no problems skipping the linseed oil; not sure of exact reason it is in, but bear in mind that Marty is in Santa Fe, and his recipe may be taking into account the very low humidity there. He is a production frame maker, so it may help with the brushing and/or spraying as well.

Joseph
 
Let me add my experience on that one. When I read Marty's recipe the idea of the linseed oil seemed sound but when I tried it everything separated and it was quite the mess. I ended up wiping it off, ditching the batch, and starting over. All I could think of is when we'd lose a helicopter into the ocean off of Vietnam and then try to salvage what we could -- oil and water don't mix!
 
unless you use a surfactant John.

If I remember right... it was Marty that used to say "shoot everything you can"

I always wondered it he some how knew how to shoot gold leaf. . . .

:D

metallicgold18kt.png
 
...everything separated and it was quite the mess..


This never happened to me, but I also make sure that I never let the gesso cool completely during the mixing/setting/straining process. I keep my heirloom mixing container (a great big old coffee can) in a warm water bath.

Then strain into jars.

Joseph
 
Bron, thanks for the memories! I was with a helicopter unit, hated seeing the photo of the CH-46 going down -- that's what I flew in during my spare, volunteer time. 'preciate it!
 
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