I am used to just using paint right from the bottle. Now, I want to thin for airbrushing and I want to keep a log of which proportions work with which paint. OK, but what do you use to measure out small quantities with some kind of accuracy? These RR paonts are expensive and only an ounce per bottle.
I use fractional teaspoons and/or drops. When I do drops, I don’t use an eyedropper; I use the “back end” of a paint brush and let it drip.
Thinkin’ on it, I suppose that’s not terribly accurate. Perhaps there’s something better…?
Ed
A really careful stickler would want to start with paint with a known density of pigment relative to its volume at any one time. I know that each time you open the lid of one of those flip-top craft acrylics, you lose some of the moisture content that came with the new bottle…whatever that was. The more you draw down the bottle’s contents (in a way, the same as saying the more used or older is the paint), the worse the loss in relative terms to what is left for the next draw.
So, a long way to say…how much paint is in a drop? What size of drop? Etc… This tells you how much water/thinner to add in order to maintain the desired range for the applicator and the application contemplated.
Without densitometers, I’d say go by gut feel, and try not to draw too much paint too often out of the dispensing bottle,…or at least, don’t forget that the paint thickens if you do.
How’s that fer gettin’ in the weeds?
Crandell
Would the bellows-type pipettes with measurement marks on the tube be suitable for using as airbrush measurement tools, or are they not accurate?
Cedarwoodron
cedarwoodron, what are bellows type pipettes and where would I go to find tham?
They sound right for the job IMHO
I’ve been painting for decades (ouch!) and I don’t think I’ve ever measured proportions. I go on looks and consistency. That is, does the paint in my airbrush have the consistency of of milk. After years of spraying I guess it all just comes naturally now how much thinning the paint I use has to be. Most paint manufacturers will say right on the bottle how much in % to thin the paint for correct flow. Testing is a must to see if that is what your situation demands. Humidity can also affect paint thinning performance, too. To check the consistency of the thinned paint, drop a toothpick into the bottle and then touch the side of the bottle. If it runs freely back into the bottle but leaves some on the way down, you are good to go.
Not all paints are thinned at the same ratios. Tamiya acrylics, a great flat paint, is thinned up to 40% while Polly Scale might be as little as 10/15%. MM Acryl paints are nearly thin enough right out of the bottle, maybe a drop or two of thinner. And never thin Aclad paints or MM Metalizers. (That’s whole 'nother story.)
Remember the old adage, how do you get to Carnegie Hall? Practice, practice, practice.
-Paul
Ya know, I don’t think you need a lot of accuracy when figuring thinner ratios. I think it matters much more when you’re trying to custom mix a color.
Ed
Bruce,
I’ve done custom paint mixes in the past when trying to achieve a particular color and have found eye droppers to be quite handy. I pick mine up at the local pharmacy and prefer the glass ones. (The rubber bulb pulls off and makes cleaning them much easier than the plastic enclosed ones.)
Granted, it’s somewhat tedious to count droplets of paint. However, other than using a scale and measuring by weight, it’s the most cost-effective way for repeated results.
I also use clear glass paint bottles (that I pick up at my LHS) to store the custom-mixes in. I mark the bottle with a piece of masking tape that contains the paint information (e.g. Pollyscale Boxcar Red), what proportions I used of each paint, and what project it was used on. Even if the paint dries up in the bottle, I have a record of what it was for.
Hope that helps…
Tom
I use small syringes. They can be flushed out with thinner or water and re-used. Send me an email if you’d like some. I’ve got lots. Been thinking of visiting you anyway.
Bob said: “I use small syringes.”
That’s a great idea. I will have to try it too.
I’ve been painting things for many years now (about 40), and I’ve always had success just using an eye dropper or pipette to measure “drops”. Yes, it’s a little tedious, but not a killer.
Some colors, just mix in a small mixing tray, but if it’s one I’m likely to keep, I use small craft paint containers with flip up lids. Using a Sharpie, I put a number on the lid. Then, on a file card, I record the name (“Muddy Water”, “Orc Skin”, “Faded Leather”, “Old Saybrook Station Walls”) so I know what it was, and the recipe in terms of parts (1 tan, 3 leather) with the catalog number of the paint (I’ve been using Model Master Acryls and Polly Scale acrylics for about 15 years now).
Sure, I will never get a perfect match, but it’s close enough that you really have to look hard to tell. The only real problem I have is when a color gets discontinued (thanks for that, Testors!).