I finally joined this excellent forum. Been enjoying it as a guest for awhile.
I‘ve seen posts/discussions here and on other forums which discussed the difficulty spraying Vallejo Model Air (VMA). Moving from a humid New England climate to a very arid high desert (Nevada) I couldn’t get VMA to spray well without constant tip dry. I tried everything, Vallejo airbrush thinner with flow improver, other retarders, etc, but to no avail. I followed Vallejo’s instruction with it’s thinners and flow improver, still no go.
The solution was not using Vallejo’s thinner. I substituted the thinner with Vallejo flow improver. I conducted experiments based on inputs from other airbrushing forums and used the flow improver at a greater ratio. I can now spray fine lines and camo patterns using my .3mm Sparmax and VMA paint with minimal to no tip dry. The ratios I use of Vallejo flow improver to VMA paint are 60/40 (camo, fine lines) to 40/60 (base coating). The greater ratio of flow improver to paint does not degrade the paint’s properties. Only the drying time is increased, but not nearly as much compared to using a more concentrated retarder product.
My Vallejo thinner is now earmarked only for washes - it works terribly in a dry environment out of an airbrush; whereas, Vallejo’s flow improver works as a thinner and is a great surfactant. It will increase drying time a bit but not as much as one would think. I spray and let sit for 24 hrs before putting down another VMA coat or camo/fine lines.
I can now enjoy my VMA paints. Vallejo flow improver has been a game changer for me.