What's the best surface prep for new wood to be painted?

Beau · 28 Apr 2016

Don't often make work to be painted but just made a front door and it's to be painted. I did my usual of light plane to clear planer ripple and a going over with ROS to 180 grit. The wood is southern yellow pine. A builder friend happened to pop around and said that the painters at work would laugh at the fine sanding it had had and rough it up with some 80grit before painting. So should I now rough it up or leave as is?

Thanks

RobinBHM · 28 Apr 2016

I generally finish with 120grit for joinery.

skipdiver · 28 Apr 2016

Agree 120 is about right. Don't want it too smooth for painting.

Phil Pascoe · 28 Apr 2016

I learned my lesson years ago. I stripped my fascias which had had paint burnt off and scores of holes filled with two part filler. I started (I thought) with 40 grit to get rid of the excrement, intending to go finer afterwards. When I stopped for tea, I looked up and thought hell, it's twenty feet in the air - a man on a galloping horse won't notice - it'll do. I rounded all the arrises , brushed the dust off and hit it with the Cuprinol then the primer - which was like painting the cloth of a pool table. When glossed you couldn't tell the difference, and when I glossed it again fifteen years later it was perfect, just slightly dull. From there on in I never sanded an exterior surface too fine. For a front door obviously 40 grit is far too coarse, but by the time you de nib after the primer and undercoat, 100 -120 is easily fine enough.