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How do I prepare an outside door to paint? Do I need to sand the door first?

I would like to paint the outside of my patio door and would like to know how to prepare the door? Do I need to sand the door or can I just clean the door first? If I need to sand what size sand paper do I use? If I just need to clean the door what is the best cleaner to use?
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Posted 2013-07-20T12:48:00+0000  by Cy3649 Cy3649

Welcome to our community Cy3649!


Thank you for your questions! What is the door made of (wood, plastic, metal)? Has the door been painted or stained already? If so, is it oil or latex based paint or stain? The answer to these questions will dictate how you will prep your door.


I will go through all of the scenarios in the hope that one of them matches your specific situation.


If you have an uncoated wooden door: If the wood is rough, you will need to sand it smooth. The grit of sandpaper will depend on how rough the door feels. If it is rough, you will want to start with a lower grit sand paper (60- 80 grit) to knock down the roughness and then move to a smoother grit (120- 160 grit) to smooth it out.


Once it is smooth, you will prime the door with an exterior primer. You can use either oil or a latex based primer.


Then, you will paint the door with any exterior paint.


If you have an uncoated metal or plastic door: You will want to lightly sand the door with an 80-100 grit sandpaper just to roughen up the surface so that the primer has something to stick to.


Then, prime the door with a primer that is intended for metal (if the door is metal) or plastic (if the door is plastic).


After the primer has dried, you can paint with any exterior paint.


Now let’s talk about the possibility of your door already having a paint or stain on there.


If your door is stained or painted with latex based paint or stain: If the paint that is on there currently is not shiny (a flat or a satin finish) you can paint over that directly without a primer. However, if the door is shiny (semi-gloss or gloss) you will want to sand the door to get rid of some of that shine. Then you can paint on top with any exterior paint.


If your door is stained or painted with oil based paint or stain: If this is the case and you want to use latex based paint, you will have to prime the surface first with oil based primer, then you can go over that with a latex based paint. If you would like to stick with oil based paint, lightly sand the surface, then go over it with oil based paint.


To determine if your paint or stain is latex or oil based put some denatured alcohol or rubbing alcohol on a clean towel and rub it on the paint or stain. If it comes off on the towel, it is latex based, if it oil based, it will not.   


As for cleaning the surface before you paint, you will want to make sure that the door is clean of dust, dirt or anything else that can be on there. Using TSP would be the most ideal, but any mild, household cleaner will work.


If you have any more questions, please let us know!


Christine :smileyhappy:

Posted 2013-07-24T18:19:34+0000  by Christine_HD_ATL
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