What is the ratio of paint to water for an airbrush?
Painting buildings?
Weathering?
Engines?
Check the paint documentation. It varies and sometimes you don't want water, but something else the mfg recommends. But it's usually very little for most acrylics commonly used in the hobby, as more of it tends to come airbrush-ready consistency already.
Mike Lehman
Urbana, IL
Check the paint manufacturer's website for their recommendations. When Polly Scale paint was first introduced, I liked it for brush painting and wanted to try it in my airbrush. Several threads, here and elsewhere, had all sorts of recommendations about thinning it with alcohol, windshield washer fluid, ammonia, Windex, etc., etc. None of these worked for me, and since Floquil was still available and I had been using it without difficulty for many years, I stayed with it.One day, for some particular job, I wanted to use Polly Scale, so went to their website to see their recommendations. While their own brand of thinner was first on the list, the only other suggestion was distilled water. They also suggested spraying at a much lower pressure than all of the other postings I had seen.Following this advice, I airbrushed 48 cars, in various colours of Polly Scale paint, without once having any problem with clogging or other issues.
The amount of thinner will also depend on what you're painting. (Pre-thinned paint, in my opinion, is a rip-off: if you wish or need to brush paint an item, it's useless, and if the thinner is distilled water, you're getting less actual paint in that bottle. Distilled water is available cheaply, in gallon jugs, at any supermarket. I cleaned-out the collection bucket in my dehumudifier and use the water, comparable to distilled, for both thinning paint and applying decals.)The no-longer-available Polly Scale paint could be thinned as much as 90% water for weathering projects, allowing a gradual build-up of effects. For everyday painting, I've seen suggestions that it should be the consistency of skimmed milk, I think - I usually do about 25% thinner, and adjust if needed.
Wayne
doctorwayneThe amount of thinner will also depend on what you're painting. (Pre-thinned paint, in my opinion, is a rip-off: if you wish or need to brush paint an item, it's useless, and if the thinner is distilled water, you're getting less actual paint in that bottle.
Wayne,
I was just observing, not judging because I didn't want someone hosing down something that was already thin gruel. I'm one of those who still brushpaints (well, Microbrush for the most part) so I like a decent consistency for that from a paint. I airbrush only rarely, using rattlecans for the most part when spraying. I do buy model paint, but it's for the sort of details a brush works best for. I suspect many other consumers in the hobby do similarly. The prethinned stuff should be available, but not without "standard" consistency along side it or the LHS may be wondering why sales continue falling.
I mix 5 millileters of acrylic paint to 3 ounces distilled water for my airbrush. Doesn't matter if it's buildings, locos, rolling stock, etc.
If you're not happy with the flow, you can make slight changes to the mixture.
Here's a chart I came across on the internet a few years ago:
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PennCentral99:
Very helpful chart. Thanks.
I did notice one possibly misleading entry. That is the recommendation to use water to thin Humbrol paints. Humbrol produces both enamel and acrylic paints. According to their website, water can be used to thin the acrylics but not the enamels. They recommend using their own thinner for the enamels.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
mlehman....I'm one of those who still brushpaints...
I think that there are probably lots of modellers who still use a brush, even if it's not their primary method of applying paint. After all, how many have the ability to paint figures with an airbrush without masking or the ability to mask them for such painting. I paint wheels (front and rear faces), axles, and truck springs using a brush as the initial step in weathering, and use a brush to do touch-up on metal details, such as grabirons and sill steps on freight cars. Such parts always need this attention, especially, as on my layout, when they often go back in their respective boxes once they reach a staging yard destination. I you have a steady hand, brush painting can often lessen or obviate the need for masking, too.A friend paints only with brushes, despite having an airbrush - he simply prefers that method and the results which he gets. As you suggest, it's okay for the paint manufacturers to offer pre-thinned paint, but please offer the un-thinned version, too.
Referring to PennCentral99's chart, the thinner for Scalecoat II is similar in chemical make-up to that of Scalecoat I, with only the proportions of the chemicals varying. I use lacquer thinner to thin Scalecoat I, and it works well when airbrushing even plastic, and also speeds the drying time somewhat. While I've not used all of the brands on the chart, the ones I have used all responded well to clean-up with lacquer thinner, even the water-based ones. Lacquer thinner, however, is not a suitable thinner for water-based paints.
As Dave has mentioned, Humbrol enamels require Humbrol's own thinner (unless you know its make-up and can find a cheaper source of it). Not so long ago, Humbrol paints could be thinned with lacquer thinner, too, and I still have some silver paint from them of that type. However, I recently bought some Humbrol enamel and it is no longer thinnable in that manner...no need to ask how I discovered that. The new label mentions petroleum distillates, and I suspect that that may mean mineral spirits, always a possible choice for enamels.