Dear Gary,
Thanks very much for your input. It is very timely. My plasterers wanted to put their scratch coat on in 2 applications, although I didn't see the advantage to this. The photograph I posted shows that first thin partial scratch coat. They tried to apply a second layer to the first layer, but the plaster had dried so thoroughly in one week, that they could not get the second coat (same mix as the first) to adhere properly. As of yesterday, they wanted to mix a vinyl bonding agent into the wetting water prior to trowelling on the next (cement/scratch) coat. This seems in accordance with your advice. Now, however, the plasterers, on the advice of on older generation plasterer in their company are going back to simply wetting the earlier coat. They say that they just have to have an extra guy on hand to do the wetting. What do you think of all this? The first "half" of the scrach coat is now two weeks old.Also, they will want to do the brown coat now right away, within 48 hours after the final part of the scratch coat is applied. What do you think of that? With the Dimitrovs, we always let the cement scratch coat dry at least a week. They also liked the brown coat ( and sand coat, if being used) to dry thoroughly before the painting layer was applied. I studied fresco in France, where we always did the brown coat the day before we painted, and left it covered overnight with wet burlap to keep it damp. Intonaco was always applied to a damp arriciato. The resulting fresco was always hard like stone. If we wait on the brown coat, and the scratch coat dries thoroughly, would you use a bonding agent between the scratch and brown coats?
I 'm sorry to hear of that puzzling comment by the assistant of Fr. Dunsten. I'm not sure what the fellow could have been be trying to say. The comment really doesn't make any sense.
I also wanted to thank you for your many postings to this forum, which I have found extremely helpful and useful. Your method of a panel-less portable fresco (using just the metal lathe) has proved to be a good technique in our studio here at the monastery. Your writings on lime and the other materials of the trade are terrific.
