Help! Oil paint cracks as it dries [Archive] - Artist Forum

: Help! Oil paint cracks as it dries


Jinglelady
03-13-2016, 06:17 PM
Hi all,
I just finished my first knife painting it came out very well. Problem is, I painted over an old painting, and the new paint is lifting off. Used Liquin to help it dry. Is that the problem? Anyone have this happen?

Thanks!
Linda Alice Dewey

Mel_Robertson
03-13-2016, 06:33 PM
hey jinglelady I hope This Link (http://www.sanders-studios.com/instruction/tutorials/writings/sanders/fatoverlean/avoidcracks.html) helps you out a bit :) welcome

TerryCurley
03-13-2016, 07:38 PM
I don't know why your painting is cracking. From what you said it shouldn't. Was the painting under it dry?

Jinglelady
03-14-2016, 01:20 PM
Meli and Terry,
Thanks so much! Meli, the article is new information for me, especially the "fat over lean," which makes sense. I did use increasing amounts of Liquin as I painted, without even realizing this is the right way to go.

Thing is, the skin or top layer of paint lifted right off the old painting, which is about 12 years old, Terry. I did use liquin for many layers, but it just lifted right off, only in one spot. It's not completely dry underneath, I don't think. I patched it, but it scares me. This painting took all winter to complete. I wonder if sitting it on the mantle over the fireplace, which heats my house, might have done it. It wasn't like a blister, more like shutters opening on a window. Just a small spot, but it scares me. Any thoughts?

adamtyler
03-29-2016, 03:02 AM
There are two types of oils used in oil painting: drying oils, which oxidize and harden, like linseed oil, walnut oil, and poppy oil; and volatile oils, which evaporate, like turpentine.* When painting oils in layers, it's important to put fat layers--layers with more drying oils mixed in--on top of lean layers, which have less drying oil. Th reason for this is that painting supports like canvas expand and contract with the weather. Fat layers expand and contract more than lean layers, so if you paint a lean layer over a fat one, the fat layer will expand and contract more than the lean layer on top of it, and the painting will crack. So, it's important to varnish paintings at the right time in the curing process. Better yet would be to take the painting off the stretchers and mount it on a board with an archival adhesive. :)

Jinglelady
03-30-2016, 06:49 PM
Thank you so much. I repaired the crack. I'm sure it happened because I dried it on my fireplace mantle. The heat from the gas fireplace going off and on surely expanded the supports and cracked it. I am getting ready to "oil it out." Shall I use 50/50 oil to turp, as I've seen it done?