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Old 20-02-07, 05:06 PM
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Bert Congdon Bert Congdon is offline
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O.K. the preventol went into the water for the pigments. Now picture a two or three pound coffee can in a pan of warm water. The gesso is made, but my cracking problem seems insumountable. I call my supplier, and he tells me my phone book has hide glue on the back, and it would crack if it weren't for the glycerin they added. A trip to the drug store later, I add one glug(he never told me how much) of glycerin. It worked, and so that has been my formula.

Now, how would I feel if my ET piece that I just spent a month on got wet. The glue is resoluble in water. I read about formaldehyde (usually preserved in a 37% solution called Formalin. I put this in just so you won't be confused at the drug store should you choose to use it.) The book said to wet the gesso with a 5% solution. I still have a bottle of that around somewhere. I don't recommend using it this way. It didn't work for me.

Think of it this way. We are working with an animal hide without the solids, hence we have either crystals or liquid. Now, how do we make this permanent? We tan it just like we would tan a hide only different, but Formalin is not working. No matter how I use Formalin, my experimental gessoed boards are cracking. A call my supplier, and the glue man tells me that Formalin tans immediately, but alum tans slowly over time. A trip to the grocery store for my little bottle of alum, and I am back at my gesso coffee can.

Alum is used to harden pickles and make them crisp. Mixed with quick lime and salt, you have white wash, Just thought I would throw that in. I was never told how much (How could he? He doesn't even know what gesso is.) I have found that a rounded teaspoon of alum in my coffee can of gesso is about right.

I mixed a new batch of furniture grade glue with glycerin and alum.
I glued a piece of canvass to 1/8" plywood and gessoed it with four coats
of chalk/glue gesso with the alum and glycerin added. I let it dry a week. This was in the winter near Chicago so the air was dry. Then I put it in a pan of warm and weighted it down. In the morning I scraped the gesso off with a sharp spackle knife. With difficulty, it peeled up like an orange peel, but white and hard. Even wet I could crunch it in my hand; it looked, felt, and sounded like egg shells. I knew then, it was not effected my water, it was permanent, and it would not crack. Now I knew I had gesso, and I am not changing. I have gessoed panels that are ten years old, and they are the same as when made.

Sorry about going into so much detail, but no one seems to believe me when I say it works. Now you can do your own experiments.
Bert
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Old 20-02-07, 11:12 PM
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Dennis H Dennis H is offline
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Bert,
I know an iconographer who puts alum in his gesso mix. He didn't know why, except that his teacher in Greece told him to.
D
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Old 21-02-07, 12:38 AM
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Dennis, That's good. I forgot to add that I tried to tear the canvas from the plywood and I ripped the plywood apart, and remember, that is after soaking all night.
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Old 21-02-07, 03:33 PM
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Bert,
I applaud you for your resourcefulness and courage. I am trying to make a living out of ET painting and, admittedly, am worried about trying anything that might prove unstable ten, twelve years down the road. If your recipe works, then you have achieved a breakthrough. Time will tell. This is how progress is made: people trying new things. I only wish I was in a financial position to be more adventurous!
Phil
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Old 21-02-07, 04:47 PM
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Thank you for your kind words Phil. If people use these methods or not, I have nothing to gain or loose. I am only trying to share what I think is 'Good Stuff' with fellow painters. (I have never gotten the courage to call myself an artist.) I can't show you archival results, but I can show you paintings nearly twenty years old. To me, the important issue is this: before using alum and glycerin, everything cracked; since using them, nothing has cracked. There is a drawback though; using alum makes the gesso rather permanent. I was taught never to use anything that can't be undone, like never use a varnish that can't be taken off. Furniture manufacturers don't use alum or any of the permanent glues, because you can't repair it by taking it apart and regluing it.

My main source of information for glue is Mr. Bjorn of:
Bjorn Industries Inc.
551 King Edward Rd.
Charlotte NC 28211
703-364-1186
FAX "-----1098

I hope he is still alive. He is a fountain of information. Did you know about the different grades? When I talk to an art supply co., they don't know what I"m talking about. As I say, I experimented with them and chose
#251. Higher numbers are harder and stronger. Lower numbers are softer, weaker, and, I think, less likely to crack. He is not cheaper, just better and informative. His glue comes in little beads called pearls.
I start with cold water, leave it sit for a couple of hours or over night. If you start with warm water, they all stick together. I'm fixen' to buy from him soon myself.

I have worked since I was thirteen, but my first job out of high school was in the research lab of a lacquer manufacturer, so I don't mind setting up little experiments, kind of fun.

Bert
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Old 21-02-07, 08:36 PM
Rosemary Rosemary is offline
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I love the idea of making a water stable gesso. I was taught by my Chinese painting teacher to add alum to rice paste when mounting ink paintings on mulberry paper to additional paper to strengthen and flatten them. The alum keeps silverfish and cockroaches from eating the paste.

I was told by a conservator not to use alum as it could cause the paper to yellow from acidity, but I have never seen any yellowing on the few paintings I still have from 30 years ago when I took the lessons.

As a chemist, I don't think this is a problem with gesso as the calcium carbonate in the gesso is basic enough to not be changed in pH by a little alum. Alum is aluminum potassium sulfate, so is a salt of a strong acid, but the relative amount is so minor, it should work well. I always hate it when I manage to remove a chunk of gesso by fiddling too much on a spot on a painting. This should prevent that happening.

Rosemary
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Old 21-02-07, 11:16 PM
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Of course, if you want to smooth the surface, let's say, for gold leaf by rewetting and rubbing with a block, alum will prevent you from reworking it.
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Old 22-02-07, 03:05 AM
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I don't know if it's really OK to use for ET (I have used it however), but you can also add small amounts of linseed oil to gesso when its hot - slowly and stirring thoroughly. So long as you don't add too much it emulsifies quite well and makes a rather creamier gesso than normal that is also a lot more adhesive, durable and flexible. It is used on canvas normally and produces a beautiful surface for oil painting. It would prevent the use of gold leaf I think though, and after the oil has hardened I suspect it would make rubbing back difficult too. It is certainly water stable though.

jeff
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Old 22-02-07, 03:20 AM
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As an addendum to that last entry, I believe you can also add whole egg to the gesso mix, so long as you don't do it while it's too hot. This is normally done if while adding oil the mix starts to separate, though I see no reason not to just add it anyway.

jeff
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Old 24-02-07, 12:27 AM
Alessandra Kelley Alessandra Kelley is offline
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I don't mean to be troublesome, but I am a little unclear. Are you saying that your gesso always cracked before you found this recipe? That seems odd to me. What was in it?
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