# Prepping MDF



## Wallace 49 (Nov 24, 2007)

Hey guys, I've got 8 MDF door casings and 2 window casings to paint. They are a craftsman style with flat 1x MDF elements. They have the usual thin primer so I know I need to reprime. I have sealed the cut ends with a watered down wood glue mixture that seams to have worked real well. My question is which oil based primer would you use in an occupied house. I HATE brush marks so I'm thinking maybe I could use aerosol cans of Zinsser Oderless or Kilz Oderless. I know Kilz seems to be a dirty word around here, but I'm curious if there is much of a diff in the two oil based products. I also have some primed MDF base and crown to paint, but the primer on these seems to be heavier. Thanks


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## NAV (Sep 5, 2008)

I'm in Ohio and VOC regulations prevent us from using solvent based materials on wood but for new MDF interior trim I would pick an acrylic primer anyway.

I'm not sure how well the material will adhere to watered down wood glue, that might have been a mistake. the only time I have heard of glue being used with paint is when you are looking for a crackle effect. Then again, after 16 years I am still learning new tricks.

About 3 years ago I sold a couple restaurants and they had new MDF board on the exterior of their outside bar area. we primed with SW PrepRite acrylic and they still have 100% adhesion today. NOTE: SW PrepRite Alkyd is interior use only, same with Killz


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## Wallace 49 (Nov 24, 2007)

The reason I want to use oil based primer is that mdf seems to soak in water based products. Where as the oil based bonds to the surface. I have seen the glue mixture perform well only on sealing the cut "end grain" of mdf. I've also seen quite a few regulars on this site recomend it. I guess what I basically want to know is what's the better product for my application Zinsser Oderless or Kilz Oderless. My gut says Zinsser, but it is not available locally. Of course I can get it online.


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## D & S Painting (Jul 9, 2010)

Wallace 49 said:


> The reason I want to use oil based primer is that mdf seems to soak in water based products. Where as the oil based bonds to the surface. I have seen the glue mixture perform well only on sealing the cut "end grain" of mdf. I've also seen quite a few regulars on this site recomend it. I guess what I basically want to know is what's the better product for my application Zinsser Oderless or Kilz Oderless. My gut says Zinsser, but it is not available locally. Of course I can get it online.




Any oil base primer will do just stay away from the water base ones. They tend to "Pucker Up" around where the nails are where the oil will lay down on the MDF better. I've been using the SW Pro Block low voc oil and have had great results with it.


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## BillD (Jun 9, 2008)

The Sherwin-Williams multi purpose oil based primer is also excellent. It drys very fast sands very well and is low odor.

Bill


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## Wallace 49 (Nov 24, 2007)

Will these SW products brush on well without having to sand out brush strokes? I'm using good brushes.


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## BillD (Jun 9, 2008)

The reason I use the stuff I do is because of how easy it sands. It does not take long before you can sand it and get a perfect surface ready for the finish.

Bill


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## D & S Painting (Jul 9, 2010)

BillD said:


> The reason I use the stuff I do is because of how easy it sands. It does not take long before you can sand it and get a perfect surface ready for the finish.
> 
> Bill


The multi purpose is great when you need quick turn around time.We used this on a set of old flat varnished doors a few weeks ago. I rolled it on and had one of my guys lay it out behind me, was dry, sanded and re-coated in about 1 hr. Both products work great but if you're doing any larger areas alone you might want to use the slower drying Pro Block with a little penetrol so it doesn't set up on you to quick.I've never had problems with brush marks with either product.


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## AustinDB (Sep 11, 2006)

I recently put 2pc crown and wainscoting in a room with some 'fancy' elements and went with a higher end SW XP which is a latex paint but used floetrol to roll/paint all the trim. The results were fantastic but did have to keep an eye on the dentil b/c with the additive the paint sometimes 'flows' down the teeth of the dentil molding. Proper pre and no brush strokes.

not sure how it would perform on MDF but did use the oil based XP some time ago and had drying issues (it was a cool time of year, but still took 4-5 days to dry!).


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## Wallace 49 (Nov 24, 2007)

OK, looks like SW multi-pupose will work. Only question is how bad is the smell factor? Bill says it's low odor. The home is occupied.


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## BillD (Jun 9, 2008)

Very low odor. I just opened a can to refresh my memory.

Bill


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## D & S Painting (Jul 9, 2010)

BillD said:


> Very low odor. I just opened a can to refresh my memory.
> 
> Bill



Bill.....Stop Huffin the paint! :laughing:

Wallace..I wouldn't worry about the odor. It's the lowest I've used in a long time and even with my asthma it doesn't bother me at all.After 30 years of painting the fumes from most oil based products are starting to get to me where I have to wear a respirator more often,yeah I know I should be wearing one anyways  but with the multi purpose there's virtually no odor I don't need one.


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## Wallace 49 (Nov 24, 2007)

OK,Thanks Bill and D&S :thumbsup:


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