Hi, in this post I am addressing the typical problems people run into when applying high polished lime plasters but can also happen on thicker marmorinos as well. Everything below is assuming that the traditional technique of 3 coats is being used. The following is taught in the Master Plaster Class at California School if Italian Plasters.
Bubbles are appearing on my 3rd coat when I am burnishing: You may have applied the 3rd coat too soon.
The 2nd coat is peeling: Your first coat might have been applied too thinly not leaving enough of a base to absorb the correct amount of water from the 2nd coat.
The 3rd coats is peeling and cracking: The second coat might not have been dry enough before you applied the 3rd coat. Make sure that the 3rd coat is pulled tightly as you only need a very thin layer.
Lines are showing up in the finish: Check your trowel for any scratches or debris. Always keep a clean wet rag with you at all times. Also keep 400 grit sand paper to polish off any tiny scratches in the trowel you might have made by picking up debris.
I am getting too many trowel marks: If anyone tells you he can do a room with no trowel marks he is lying. Trowel marks will happen and if the are not too thick, they are part of the finish. The thick ones are made when the back of the trowel has built up plaster on it. Every time you load up for more material you should scrape the back of the trowel with your spatula.
I've got thick wet spots on some of my wall but the rest is ready to burnish: Keep a hairdryer on hand and gently help dry the thick spots so that you don't miss the burnish on the whole wall.
One wall is darker than the other: You have to make sure that you are burnishing your walls at the same dryness level. If one person is burnishing when the plaster is on the early side of the "in love" window, it will be darker than one burnishing on the dryer time of the window.
I am leaving marks on both ends of the trowel when I apply plaster: This means that your trowel isn't convex enough. Press on all for corners of the trowel to correct it.
I am leaving dark grey marks on the light plaster when I burnish. You aren't using a good plaster. It probably has silica in it. You should switch to a plastic trowel or a CD case to burnish. Also, some plasters are burnishable with paper.
