Daine W. recently asked me how to care for brushes when painting oil paints outdoors? Do you have to bring along a portable brush washer, or is there another way to deal with this?
There are a few things to do to care for brushes when painting outdoors.
First, always make sure that your brushes are not standing on their heads whenever you are in transit or when you are painting. That means NOT LEAVING YOUR BRUSHES IN YOUR JAR OF TURPS! Other than letting paint dry on your brush, this is the quickest way of ruining your brushes. If you don't have room on your easel for laying down your brushes, then you can lay them on the ground or even stick them handle first in the ground.
Second, if it is sunny outside your paint will dry faster, even on your brushes. If you have a brush with paint on it and have decided to use a different brush for awhile, rinse the paint-filled brush in your turps before you set it aside. Paint can get a quick "skin" on it in the sun. This can cause problems when you go to use it again.
Thirdly, I never fully clean my brushes while in the field. There is enough to carry to worry about bringing enough turps and other items to clean in the field. When I am done painting, I will make sure I have rinsed my brushes as best I can with the turps I have on hand. I will wipe them with a rag. If I am just a short way from home (a half-hour or so), I will put the rinsed and wiped brushes in my paint box and take them home to clean them.
If it will take longer to get home, I will clean and rinse like above and then dip the brushes one more time in the turps so they are fully wet. I will then stick them in a plastic baggie with a zip top. I will close the zip top and try to get as much air as possible out of the baggie. If my brushes are wet with turps and there is no air, any paint on them can't dry out.