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Old 23-04-07, 11:40 PM
maplebrush maplebrush is offline
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Default Ground Issues - Measuring Progress for a Newbie - Part 1

I don't feel bad posting this. This board has been way too quiet. Now you all have something to do.

OK, it finally quit snowing around here, the sun came out and with my blood levels of vitamin D a little more elevated, I took the plunge to prepare my own ground. I went off to a lumber yard and got several types of wood samples (poplar, marine plywood and maple veneer) and printed out Bert's instructions for mixing up rabbit skin glue (see previous posts about cracks in a panel). I put some rsg in a coffee can and put in just enough water to cover it. It immediately developed the consistancy of really overcooked oatmeal (I know. I'm an expert at overcooked oatmeal). Roughly 30 seconds later, it evolved into a fairly inert blob of rubber. I added more water, got about 45 seconds of the oatmeal state before it rubbarized. I finally just filled the whole can with water and it stayed oatmeal-like for about 5 minutes, long enough to glob it in a panic onto my board and linen. (just wait til I get to part two: the gesso that ate my kitchen)

My question is this: Hey Bert! Is this what's supossed to happen? I gave it a day to dry and it dried tight (you bet it's tight!) but there are little balls of RSG all over it and it's blotchy. Also, the poplar is warping, even though I coated both sides of the wood. (The marine plywood is not. The maple veneer is warping, but due to the rapid rubbarized metamorphosis of my glue, I couldn't finish getting on the coat, so I'm not even goiing to worry about that.) I ended up sanding to get off all those little balls. Did I screw up? How?

I'm right in the thick of gessoing. I talked family into leaving the state for the evening so I can trash my kitchen without snide remarks. So far......ummmm......well.....I'll keep you posted.

-M

:lol:
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Old 24-04-07, 02:34 AM
maplebrush maplebrush is offline
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Default Ground Issues - Measuring Progress for a Newbie - Part 2

OK. This didn't turn out to be nearly the disaster I had predicted. I now have 3 boards drying with a gesso surface that looks a lot like icing on a weading cake. I think that's right. Is it? Tomorrow I will sand, probably a lot because I put on a ton of coats. Why did I put on a ton of coats? Because I didn't read very far past the recipe for Gesso on the ET Society's web site. I didn't realize that ithe gesso needed to sit for an hour after mixing in the chalk. As a result, my first 20 coats were rather thin (as in 'anorexic') and spatterings of gesso had become a major decorative theme on the walls of my kitchen. Had I let it sit (for all you fellow newbies who are as thorough in your research as I apparently am) I would have seen it thicken up and go from the consistancy of 2% milk, to cream, to mayonaise, to mashed potatoes. However, just letting the pot sit in warm water took the gesso almost immediately back to the 'cream' stage. Panel of experts, I ask you, did this hurt the strenth of the glue? Will I have problems down the line?

I learned all this because after I had applied those first skinny layers, I had to vent. The gesso sat while I wrote part 1 of this tirade and was just about perfect when I went down to tackle it again.

So, I think all is well. The gesso is smooth with no bubbles and I have learned that it is remarkably easy to clean up. All is good.

Am I on the right track?

Thanks for what will no doubt be your expert feedback.

-M
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Old 24-04-07, 03:59 AM
David McKay David McKay is offline
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Hi M: Thanks for the very entertaining post. Who says egg tempera painters have no sense of humour.

With all due respect to Bert (and I mean that sincerely because I really do respect him) I do not like the "coffee can formula." I like to measure things that are as finicky as size and gesso. There is no mention of how big the coffee can is etc. etc.

The standard formula is as follows. Simply soak one ounce (by weight) of rabbit skin glue crystals in 16 ounces (by volume) of water until the crystals have swollen to their maximum. This will take less than an hour, so soak them for an hour to be sure. Then place this (your undercooked oatmeal) in the top of a double boiler with some water in the bottom part and heat (stiring a little now and then) until the size is hot. Apply as a size or add whiting (2 parts whiting to 1 part size) to make gesso.

It is best to size the panel and let it dry until the next day before gessoing. It is also best to mix up a new batch of size on the gessoing day. That means, you will need nowhere near the 16 ounces of size on the first day because that much size would probably cover 100 square feet of panel! I have found that an ounce of crystals is about 4 teaspoons in volume, so you could use a couple of teaspoons of crystals and 8 fluid ounces of water if you wanted to and then throw out the remainder and mix up a new batch when you gesso a day or more later

Yes, you are on the right track. David
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Old 24-04-07, 03:27 PM
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RobM RobM is offline
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Hi M,
Loved the tone of the post. :grin:
You can't really go wrong if you stick to the recipe on the ET site
http://www.eggtempera.com/grounds.html
I would disagree with David on the size being hot.....it should not exceed 135 degrees as the glue breaks down.
Good luck with it.
Rob
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Old 24-04-07, 03:47 PM
maplebrush maplebrush is offline
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Hi Rob,

That was the recipe I used and it did work really well. I just forgot to let it sit for a while and can affirm that gesso at 110 degrees has the consitancy (along with the speed and splattering ability) of water. Letting it sit too long allows it to get too thick, but there is about 10 minutes where it's just perfect. What struck me is how rapidly it goes back to the splatter stage when the container is put into warm (not hot) water. It's really easy to control.

Does that hurt the glue any, to be warmed up and cooled off multiple times?

-M
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Old 25-04-07, 12:48 AM
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Dennis H Dennis H is offline
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M,
I use a cheap electric "crock-pot" to warm my glue and gesso instead of a bain-marie. I guess Crock Pot is a brand name -- so "slow cooker" is probably the correct term. It has a top and warms its contents low and slow. I simply need to stir the mixture gently and regularly, and give it a sip of water every now and then. Anyway. my pot seems to keep it all at a good temp, without the cycle of heating and cooling that you mention.
D
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Old 25-04-07, 01:14 PM
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PhilS PhilS is offline
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Never thought of a crock pot, Dennis. I'll have to start checking out yard sales.
I'm posting a word of warning. In the past, I have advocated using Fredrix Dry Gesso mix. No more. I've had three bad batches in a row, where the rabbitskin glue refused to dissolve. I even let one batch sit for two days. I ended up with hard grains of glue on the surface of my panels. That in itself was a problem, but when I sanded, the undissolved grains would pop out, leaving tiny pock marks, which was even more of a problem. I wrote Fredrix a long letter several months ago. No response. Now a friend of mine called to say that her Fredrix gesso mix is doing the same thing. Apparently the rabbitskin glue Fredrix is using is defective.
It's too bad. I've been using their product for 15 years. If they respond to my letter and assure me that the problem has been resolved I will give them another shot. Until then, I guess I'll go back to making my own gesso.
Caveat emptor.
Phil
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Old 25-04-07, 02:24 PM
JanMoore JanMoore is offline
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Default Gesso Dry Mixes

I've tried several Dry Gesso Mixes. I first started using Grumbacher's but this is no longer available. I didn't like Fredrix immediately (and this was several years ago) because it was too hard. I highly recommend Gamblin as a brand. Since Robert Gamblin is an artist himself, his products seem reliable, including his dry pigments, which I have also used. Gamblin puts out both a Dry Gesso Mix and Rabbit Skin Glue. This can be found at Jerry's Art-o-Rama or by catalog through Cheap Joe's! The Gesso mix is easy to use and gives a soft (i.e., sandable) smooth surface.
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Old 25-04-07, 08:49 PM
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DLH DLH is offline
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Gesso is so quick and easy to make from scratch I canít see any point to the mixes. Maybe Iím spoiled, but the Utrecht brand glue I get is ground fine enough that it dissolves easily in warm tap water. It is ready to use with less than a minute of stirring. I reheat with a microwave, keeping in mind that it doesnít heat evenly. I use a very low setting.
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Old 26-04-07, 02:23 PM
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RobM RobM is offline
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M

Quote:
Does that hurt the glue any, to be warmed up and cooled off multiple times?
I usually have the gesso warm.....apply a coat and then put the gesso pot back into my make do double boiler to keep warm. I have not experienced any problems with the gesso warming up and then cooling. If it does look as if it is about to gel I just turn the heat up until the gesso is liquid again.
R
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