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  #11  
Old 19-09-03, 03:15 AM
Anonymous
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Making good gesso is difficult. Applying it properly is even trickier, I know because we make custom gesso panels by the thousand. They receive eight hand-rubbed coats of gesso. They do not crack, check, yellow or have pinholes, nor do they suck up the paint, leaving it underbound.

The glue is very important, as is it's proper handling. We import ours from a small maker in Portugal and it is flawless. It's also real rabbitskin glue, not the calf glue that masquerades as being made with real rabbit skins. The French make an excellent rabbitskin glue in sheets, a bit difficult to work with, but otherwise excellent.

Whether you use our Portuguese glue or the French sheets, proper handling is important. The water should be clean and free from minerals or softeners. It should be soaked in tepid water until it has absorbed the liquid. It is then heated to no more than 135F, that means that a double boiler is way too hot. The proteins strands unravel past 135F. Floating your container of glue in a pot filled with hot tap water will be safe and efficient. It should not be heated much past that point.

The main solid in our gesso is a talcum-fine powdered marble. A small amount of titanium dioxide is added for opacity (the ancients used white lead). We mix the solids into the liquid glue and allow the mix to congeal. We then store it in the fridge overnight and heat it. This process removes the bubbles that cause pinholes. We also add a surface tension reducer that guarantees that there will be no bubbles.

We offer a powdered mix (Easy Gesso Mix) that is similar to the gesso we make in 20 gallon batches for application in the shop. The mix has the surface tension breaker in it. Check it out at http://www.studioproducts.com/store/ It should be helpful in producing the flawless ground that egg tempera demands.