I got this since I paint in my room with mineral spirits and one day thought I should start worrying about my health. The Gamsol website does recommend that mineral spirits be used for under painting and I’m not sure why? Maybe using too much solvent free fluid can cause cracks later on? I haven’t tried that for myself so I don’t know if that’ll happen. Other than that it at least cuts down my usage of mineral spirits and I feel a little safer to paint in my room that way. It’s just a tad bit thicker than mineral spirits but functions the same way. I had absolutely no problem transition between mineral spirits and solvent free fluid so I very much recommend this! I use a palette knife to dip into the bottle and tap it onto my palette (it’s a little goopy that way but not as goopy as liquin). Just remember the wipe or rinse the palette knife because when this dries it looks wet but is just sticky.