The viscosity of milk paint directly affects the ease with which the paint can be applied and the smoothness of the painted surface. True milk paint only comes in powered form and must be mixed with water before use (“pre-mixed” milk paints are really acrylic paints). Thick paint doesn’t flow off the brush easily and the resulting surface is rougher. Extremely thin paint leaves bubbles on the surface and is runny. Paint manufacturers often recommend a mixture of paint that is thicker than what I like.
For my milk paint DVD, I discovered you can make a viscosity measuring cup from a pepsi bottle. Drill a 5/32 hole in the lid of the bottle, remove any drilling burrs from the hole and cut the bottom of the bottle off. You now have a rough equivalent of a #4 Ford viscosity cup. It looks like this:
Hold your finger over the hole in the lid of the bottle-turned-viscosity-cup and pour a half cup of paint into the cup. Count how many seconds it takes for the paint to flow through the hole. Stop counting when the stream of paint breaks (don’t keep counting to the last drop). I like paint that takes 10-13 seconds to flow through the hole.
I am on the Orange County Studio Tour the first two weekends in November. About 80 studios in my county are open for visitors: woodworkers, painters, sculptors, jewelers, etc. I’ll have a showroom set up in my shop and will be doing turning demos. Come by, eat some snacks and say hello!
Saturday Nov 4th, 10-5
Sunday Nov 5th, Noon-5
Saturday Nov 11th, 10-5
Sunday Nov 12th, Noon-5
That is very interesting. Any idea if the #4 ford cup would work for other water-based finishes? Like any viscometer, it might just be a reference. I would expect the shape and surface of the bottle would affect the surface tension of the fluid, which is probably why one can find them from 10-300$.
Yes! Viscosity cups are commonly used to measure paint and other finishes. My home-made cup seems to be slightly less accurate than the $12 cup I bought, but it’s plenty accurate for milk paint. A google search will yield lots of info.
affects not effects in the first line; it will change the effect!
Good point! I’ll fix it. Elia
what are your starting proportions?
I usually start with one part dry powder to two parts warm water, by volume . mix well using a egg beater, let sit an hour or so, the re mix and strain through a paint strainer obtained at the local Lowes or Home Depot.
One has to start with a formula prior to the pop bottle trick… am I close?
Each brand and color of paint is different, but that sounds about right for the dark colors of Old Fashioned brand. Light colors and Real Milk Paint brand need less paint, 1/1 or 1/1.5