My kids has a wooden bird feeder kit and I’m planning to build bird houses with them soon. For now, they at least want to paint the feeders and I’ll talk them into staining the houses. However, what type of paint should I get for outdoor use? Will regular hobby store acrylic paint last? Should I clear coat it or use a clear poly?
If it wuz me, I would use an exterior alkyd (commonly called "oil based") paint if oil based paints are still available for sale where you live. I am biased toward oil based paints simply because they form harder and stronger films that stand up to the elements better than latex paints, and oil based paints have a much simpler and more reliable film formation mechanism. That is, there are lots of things that can go wrong to screw up the way latex paints dry to a solid film, but it's hard to prevent an oil based coating from NOT forming a proper film. You can paint a fence in a Manitoba blizzard in January with an oil based paint and the paint will remain tacky all winter long, until the warm temperatures come back in spring whereupon the oil based paint will dry to a proper film. They're more durable and less problematic than latex paints, but they cause smog in our cities and so they're being regulated out of existance.
That word "acrylic" simply means that the paint is made out of the same kind of plastic that Plexiglas is made of. Since resins made of that kind of plastic can be easily suspended in water, acrylic paints are typically water based paints. Most good quality interior and all exterior latex house paints in North America are "acrylic" paints too. However, I don't know enough about hobby store paints to know if they contain mildewcides and UV blockers like exterior house paints do. Since your bird houses are going to be outdoors, I'd use the paint I know will have those additives in it to protect the wood.
So, if it was me, I would just use an exterior house paint (preferably an alkyd, but if you can't get alkyd, then a latex) rather than a hobby store paint. Buy a mistint for $5 per quart. You'll get a better paint for less, and the birds won't care.
If you're planning to stain bird houses, then clear coating over an exterior stain with a clear coat meant to be used over wood outdoors be a good idea in my books. It would add more UV blockers between the Sun and the wood, and would help prevent the wood from absorbing rain water, expecially if you put an extra coat or two over any exposed end grain of the wood.
You see, the primary difference between an interior and an exterior wood stain is that the exterior wood stain will have some binder resin added to it. That binder resin forms a plastic film over the wood as the exterior stain dries. Because there's not very much binder resin, it's a very thin film that forms, but it's sufficient to do the two jobs that film needs to do, which are to suspend the mildewcides and UV blockers added to the stain to protect the wood from the Sun and stuff growing on it, and secondly to prevent the wood from absorbing rain water. That's cuz it's the absorbtion of rain water through the end grain of the wood that causes unprotected wood outdoors to crack and split at the end grain.
So, the binder in an exterior wood stain should be sufficient to protect the wood, but adding a clear coat meant for use over wood outdoors will help that binder film do it's job. What's important, however, is that any clear coat you buy is meant to be used over wood and outdoors. Otherwise it may not have UV blockers and mildewcides in it (which are needed outdoors) or it may form a film that's too hard to stretch and shrink as the wood substrate expands and contracts with seasonal changes in it's moisture content. If you check that any clear coat you buy is intended for use over wood outdoors, then it'll have UV blockers and mildewcide in it, and it'll dry to a soft enough film that still has enough elasticity to stretch and shrink with the wood.
Or at least, if I were staining bird houses, I wouldn't hesitate to put such a clear coat on over the dry exterior wood stain. It might not be needed to protect the wood, but it certainly wouldn't do any harm.
Hope this helps.
(Post again if you want to know how latex paints dry to form a film made of Plexiglas or why unprotected wood outdoors will split at it's end grain due to absorbtion of water.)
The end grain of wood after only a few wetting and drying cycles:
The end grain of wood after many wetting and drying cycles:
http://image.shutterstock.com/...end-grain-514196.jpgThis message has been edited. Last edited by: Nestor,
Any exterier latex paint will work fine, no sealer needed.
Not a great idea to have kids painting with oil based paint.
Far harder to get oil based off anything they spill it on and clean up the brushes. Plus all the cleaners are toxic.
As you are talking about feeders it must be outside of your home then exterior latex paint will be the proper paint for bird feeder.
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