I noticed in your painting of the guys at the watering hole that you began with a flat tip brush...when do you use the rounded brushes? What's the biggest difference between the flat brush & the round brush?
I like the flat brushes better and I don't use round brushes very often sometimes not at all. The flat brushes allow you to make a straight line by using the long side of the tip. Also I like the faceted look of using a flat brush. The round brushes are almost like a really big tip on a magic marker. In fact you may want to look at a chisel Tip marker and around Tip marker and that will give you the idea of how round brushes and flat brushes work.. There is also a long flat brush that is called a " bright."
Also can I use mineral spirits to make oil paints into a wash & clean brushes? What's the best thing to use for longevity of the painting?!! Is mineral spirits okay??? Thanks!!!
Mineral spirits are good to use for slight thinning of the paint and for cleaning brushes. Some sources will tell you to use other stuff but mineral spirits are great that's what I use. Also, try to find what's called "odorless" mineral spirits. You may have to buy it from an art supplies store rather than a hardware store. If you do not live in California you can order it online from Dick Blick and they will ship it directly to you. Something that I do with my brushes is at this point I don't actually ever completely wash them with soap and water. I went to Safeway and I got some walnut oil and what I do with the oil is I put it in a tuna can. Meaning I just use a small – for about a tablespoon of walnut oil into the dish after I got my brushes as clean as I can with the mineral spirits. I wiped the mineral spirit off the brushes and then I did the brushes in the walnut oil and get them oiled up and let them sit between painting. When I go back in the next day to paint I just rinse the brushes in mineral spirits and the walnut oil comes out and the brushes are very clean that way they don't dry overnight.
Use this paint thinner in all types of artist oil, oil-based paints, and Varnishes. Also works as a great brush and accessories cleaner. It can be used like turpentine with no unpleasant odor. Available in 16-ounce of odorless paint thinner. Danger.