Finishing Milk Paint Outdoors
Milk paints are tough, but probably need extra protection in an outdoor application. October 27, 2005
Question
I'm building a rustic garden shed/potting cottage for a client and want to use milk paint on its porch and probably in other places (top of a potting bench, etc.). There's also a long expanse of redwood fence, unfinished and aged to grey, they want done in milk paint. I'd like to find a finish which will protect from water, but interfere as little as possible with the milk paint patina, coming as close as possible to what a waxed finish would look like. No gloss or shine.
Forum Responses
(Finishing Forum)
Milk paint is pretty tough stuff. Not much will strip it off - even modern strippers have a tough time removing it. I don't think that you need anything else besides the milk paint. Of course, it will age with the weather, but everything will if it's outside long enough.
From the original questioner:
Thanks. So, you don't think a sealer would be needed?
I use milk paint as a paint and as a stain. I thin it out even more when I want to use it as a stain. Milk paint powders are pretty tough by themselves, but for an exterior use, I think that a coating of some sort would be necessary. Which brand of milks are you using now and what do the directions say as far as coatings? A coating of any kind will change the overall color of the original unfinished color. The milks I use have their own coating (which I don't use), and they claim that it does not alter the original color "that much." I think that a project such as yours would require a protective coating.
From the original questioner:
Yes, I think a coating would be necessary unless I let the wood age and do its thing naturally. But, retaining the color decided upon is important to the client, and to me from an artistic standpoint. That's why I'm looking for the sealant which would least affect the color of the milk paint as stained. I've heard that if you leave it alone, without sealant, it may age to a nice patina of its own accord. I just don't know if this approach is foolish. Many say that MP is such a tough customer that the risk can be worth taking. Thanks for trying to think it through with me.
There is definitely a need to add a protective sealer/finish over the milk paint as much to protect the wood as for any other reason. Unprotected, the wood will warp, crack, etc. Milk paint itself does not offer sufficient protection. As to a sealant, if you want one that doesn't affect the color noticeably, I suggest that using the exterior tint base used in mixing the deepest colors of paint (acrylic latex) should work. This tint base (for deepest colors) will dry clear and should provide exterior protection, having mildicides and UV additives.
