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Painting interior OSB

Hi there,

I've now primed the inside of my shop with "Kilz" using a to paint it.  I would like to use a paint sprayer to apply the exterior oil-based paint I bought.  I was told this would be the most durable coating to use in there (I've bought it now, and not planning on taking it back!!).  I would like some input on what type of sprayer I should use to apply this type of paint.  It's thick so I CAN thin it and possibly stretch it out a bit too.  I'm thinking airless (what brand? Model?) or HVLP (of which my uncle owns and is willing to lend to me).  Any advice would be appreciated.



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Posted 2012-09-12T15:09:55+0000  by Tucker3878 Tucker3878
OSB is not a code approved wall finish material as it's flammable. Applying oil based paint will only make it even more flammable and potentially emit toxic fumes in a fire. Drywall is cheapest code approved non-flammable wall finish. Please do not say that "it's only a shop" or "we don't need to be up to code here" as a shop is one of the environments that is at the highest risk of fire!
Posted 2012-09-13T13:37:55+0000  by msrose

It's a great day in the Paint Department Tucker!


Spraying oil-based paint is very common with both airless and HVLP.


Most oil-based paints are very thin and will easily flow through a compressor driven HVLP ... like your uncle's.


Three things commonly happen when DIYers who are unfamiliar with siphon-feed sprayers attempt their first effort:

1) They take a bit more time to get the combination of air pressure and paint volume adjusted to create an even flow;

2) They change the viscosity by thinning too much and apply very thin coats ... requiring three or four coats to cover; and

3) They forget to drain the moisture collector resulting in water drops being driven through the hose and out onto the surface.


In addition, oil paints are very sticky. You'll want to remove and/or clean any potential dust sources. This may include turning off your AC system well ahead of spraying and not turning it back on for about six hours.


With those cautions, I like the idea of using HVLP for oil-based paints.


And I like your selection of oil, because it is very durable.


NOTE: I am often asked, "Can't I leave paint in the sprayer overnight?" My answer: absolutely not! Because you're using oil, have plenty of mineral spirits on-hand, and clean your tools immediately.


FINALLY: HVLP Siphon guns (that pull paint from a pot up to the tip) require detailed adjustments of both air pressure and paint volume. Try purchasing a gravity feed gun to simplify your project ... the pot sits above the tip and gravity pulls paint down into the gun. This eliminates having to siphon or pull paint uphill, and ultimately make adjusting the gun much easier.

Posted 2012-09-13T13:52:23+0000  by Pat_HD_ATL

Thanks Rose,


I agree with your statement but somewhere along the line someone told me OSB is approved, and it is used in TONS of shops in and around my area.  I don't really want to open up a can of worms with the inspector by asking him because I am NOT about to rip it all down at this point, if I can't get insurance on it, I can't get insurance on it.  Thanks for your input though.



Posted 2012-09-14T21:02:25+0000  by Tucker3878




Here is a situation where if it were me, I would rather roll that OSB rather than spray it.  Spraying oil paint is not fun. It is stinky and sticky with the over spray getting on everything, including you! Once done, it takes lots of not inexpensive paint thinner to clean the equipment. Then what do you do with dirty paint thinner.? You can't just throw it away.


I do like oil paint on shop walls.  My former home shop had oil paint on all the walls, although they were drywalled.

 OSB tends to be heavily textured and porous. Spraying does not force paint into the surface as does the physical rubbing by roller and brush.


As to whether OSB is allowed for wall finishing in shop areas: after a quick google search, it is not completely clear if the various national building codes allow it or not. In any event, the final arbitor is the local building department. They can establish what ever standard they wish, subject possibly to state building codes in some states. I personally would not feel unsafe with such a finish on my shop walls.

Posted 2012-09-16T04:03:14+0000  by ordjen
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