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Oil-based v. Water-based

With all the posts going on about painting furniture and such, I did a bit of digging to come up with a list of the pros and cons of both latex and oil based paints.

 

 Water-Based

Quality interior latex paints provide better long-term flexibility, that is, resistance to cracking and chipping. Latex paints also tend to resist yellowing with age in areas protected from sunlight. They emit fewer odors, clean up with water and are not flammable. Latex paint takes a shorter amount of time to dry than oil paint.

Pros

  • Low odor
  • Faster dry time
  • Water clean-up
  • Long-term flexibility
  • Non-yellowing
  • Not combustible

Cons

  • Relatively small open-time (amount of time paint can be brushed before it sets)

Oil-Based

Oil-based paints offer superior one-coat hiding and better adhesion to difficult surfaces (such as those not thoroughly cleaned). Oil-based paints allow for greater open-time (or length of time the paint may be brushed before it sets), superior resistance to "blocking" (or face-to-face sticking) and resistance to abrasion, once cured.

Pros

  • Hard, durable
  • Moisture resistant
  • Greater flow and leveling
  • Greater open-time

Cons

  • Yellows with age
  • Strong odor
  • Requires solvent cleanup

Ok, so you read this list and think to yourself, I've made a mistake in choosing the right paint. I don't want to have to redo this whole project!

 

All is not lost and in most cases there are work around for most of the issues. We'll start with the water-based products.

 

To alleviate the open time issue with a water-based product, use Floetrol by Flood. It is a paint conditioner that will lengthen the drying time of the paint, giving you a smoother finish and better brushability. As for the problem with blocking that is mentioned, if you've painted a piece of furniture with a lesser quality water-based paint and experience the problem of items sticking to it, usually a light coat of paste wax will solve the problem. Blocking usually results from using a lesser quality paint, not allowing proper drying time between coats, or application and drying in poor environmental conditions (too hot or cold, high humidity).

 

Also, when dealing with primers, the longer you give the primer coat to cure (aka dry) before topcoating, the stronger the bond. Most primers will reach their maximum adhesion capability around 7 days. That's not to say you have to wait seven days before you can paint over it though. Look at it this way, the label says you can recoat in 1 hour. If you wait 2 hours, you're better off than 1 hour. If you wait 4 hours, you're better off than two. If you wait 24 hours... You get the picture. Now, primer coats also have a life span and that is about 30 days. This is why that pre-primed woodwork always performs better with a fresh coat of primer on it than just going straight to paint. The primer is applied at the factory to protect the wood, but more so to hide the finger joints used to join lots of cuts of shorter pieces of wood used to make that long piece of molding.

 

With oil-based products, there is the issue with yellowing. Yellowing of oil-based products has to do with the type of oil used to make the product. Linolenic fatty acids yellow quicker than oleic fatty acids. If the finish product contains linseed oil (from flax seed) as its base, it will yellow quicker than a product derived from soy or corn oils. What can you do to stop or reverse the problem of yellowing? Exposure to sunlight.

 

Sunlight has higher energy levels than any artificial light. Indirect exposure to sunlight will reverse the effects of the yellowing fatty acids. So the more natural light in the area where the oil-based finish is, the less yellowing will occur. Notice it was indirect exposure. Long-term, direct exposure to sunlight can cause fading. That being said, if you notice a piece of furniture starting to yellow, take it outside on a sunny day for a few hours. You'll see the yellowing start to diminish.

 

What about the smell? Wear a charcoal filter respirator if you're prone to breathing problems when dealing with oil-based paint smells. And even if you're not, it still isn't a bad idea. The second and just as important, plenty of ventilation. We're not talking fans, plenty of ventilation refers to fresh air exchange. You want plenty of fresh air to dilute the VOCs being given off by the oil-based products.

 

Solvent clean up is an issue that you just have to accept with oil-based products. There are some new alternative, safer solvents by Kleen-Strip that lessen the bad side of solvents, but they are still solvents, just not as strong.

 

Hope all this helps you make a better informed decision.

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Posted 2011-09-24T03:31:20+0000  by Paul Paul
 
 

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