Can anyone tell me why you can't mix oil and latex paint? I've done it and it works?

Answer 1

You aren't supposed to b/c they aren't made of the same things and will seperate out eventually. At least that's what I gathered from taking Chemistry. You probably painted right after you mixed them together so they didn't have a chance to seperate.

Answer 2

Hiya Katherine..

There's no denying that if you mix a latex and oil together - and keep the solution mixed up - that it can be applied to a surface without any apparent disastrous consequences...

The key word in that sentence is "apparent"...you've gotten a lot of answers so far, and none of 'em are exactly correct as to the reason why you can't (or shouldn't) mix the two. The truth is, most manufacturers regularly mix oils/alkyds and latexes together in primers, interior and exterior paints (often called, creatively enough, alkyd modified latex)...The reasons for alkyd modification are plenty - ease of application, longer wet-edge, better penetration, serves as a binder for chalk or dust on a surface to be painted, etc. ...

There are sundry products on the market that, when mixed with a latex (acrylic) paint, gives the latex paint the oil based characteristics of penetration and chalk-binding (probably the best known brand name is Flood Company Emulsa-Bond, which is simply stir-in alkyd modification).

And there are many commercial/industrial products on the market that are "water-reducible alkyds" - oil based products that clean up with and are thinned with water. The reason water reducible alkyds are popular right now has to do with the environment and v.o.c. (volatile organic compounds) regulations restricting the use and/or limits of targeted solvents.

The reason these products work, when it appears they are composed of incompatible products, is due to the process of emulsification...This process uses solvents, soaps and engineered resins to allow seemingly opposite components to mix together harmlessly without disrupting the finish products ability to "cure" (driveway sealer is a perfect example of an emulsified product that mixes coal tar resin with water)...

...and the products ability to "cure" is the reason why you don't want to mix oil and latex paints...since the products you've mixed together do not contain the proper resins or the necessary emulsifiers, the finish coat cannot "cure" the way it was intended. In the case of alkyd/oil base paints, the paint film cures through oxidation - latex (acrylic) encapsulation of alkyd molecules can (and usually will) disrupt this oxidation process. Latex (acrylics) cure through coalescence - and unfortunately, the presence of oils disrupt this process.

What happens now that you've mixed the two together and they appear to have dried? ...Probably nothing - although with their inability to cure properly, they may never reach the optimum level of adhesion, flexibility, washability and stain resistance that the manufacturer initially intended and designed the coating to produce - at some point in time, this amalgam may lose adhesion from the surface - or may be difficult to re-coat successfully at a later time.

So, if you're still awake after that long winded explanation, try not to do that with paint in the future. I hope this information is helpful to you - good luck on your projects.

ric

Answer 3

it doesn't work and you are either mistaken on what you have done or your not paying attention .Picture a salad dressing pour in the oil and now pour in the water do the y ever stay mixed NO because oil and water do not mix 3rd grade chemistry you may paint over latex with an oil but mixing together NEVER

Answer 4

both adhere differently to surfaces. may look okay now but eventually after the elements get to it, parts of your paint job will look like crap. one is oil based, the other is water based. you know how oil and water don't mix.

Answer 5

it's like adding water to your engine oil, they don't go well together. the chemical composition of the two is totally different, like it says one is made of oil and the other made with water.

Answer 6

cant and shouldnot are totally different.wait a while .see why this is not a great idea.

Answer 7

you can't, becauz "they" say you can't.