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Sanding to what grit for painted project

7K views 13 replies 10 participants last post by  paxorion 
#1 · (Edited by Moderator)
Rather than hijack another thread, I wanted to know what grit I should sand a paint-grade poplar project to. I'm working on a step stool and I am at the point where I want to sand prior to assembly. What grit should I sand to? In the past I've always done 80 → 120 → 220.
 
#4 ·
Might want to start sanding Poplar with 120 or 150 grit sandpaper and finish with 180 grit before applying paint.

Would not think about sanding Poplar with 80 or 100 grit sandpaper unless surface really rough or lot of tool marks. Poplar is a hardwood, but very soft you can really create more work for yourself sanding with too coarse grit sandpaper.
 
#7 ·
If you want it real smooth take it to somewhere around 150 and then slap a coat of primer on it and sand that back from 150, 200 through 320, and 400. Maybe repeat or at least put another coat of primer on (generally the paint still looks better imho if the primer is knocked back flat at least)

This looks nice for gloss paint, expecially on more porous wood.

For less shiny items I'd get less excited.
 
#9 ·
+1 to recommendations to go light. Don't sand too smooth on a prime paint job. With poplar especially you need a rough enough surface for the primer. You can sand poplar to a point it won't take adhesion. I echo rum sand rough and then prime, sand your course after that.
 
#10 · (Edited by Moderator)
hmm, interesting thoughts. I should better clarify the project. This will be a child's step stool assembled with glue and screws. The primer I will be using is Zinsser 123.

So it sounds like my game plan will be to…

  1. Sand with 120 grit until the surface is flat enough
  2. Pre-prime what I can (or choose to)
  3. Assemble with glue and screws
  4. Plug/fill holes and spot sand with 120
  5. Finish priming
  6. Scuff-sand if needed
  7. Put on the finish paint
 
#11 ·
I usually used either four or five grits depending on the finish, painting goes to 180, stain, varnish, oil, poly, lacquer, etc. goes to 220.
 
#12 · (Edited by Moderator)
Thanks everyone for the advice. Seems like there are several schools of thought on the grit to sand to. With most saying sand to 180/220, others advocating for a smooth enough finish for primer to adhere to. I think I'm going to have to go with my gut and see how this works:
  1. Sand with 80? → 120 → 150? → 220 grit prior to assembly (any grit with ? will be subject to necessity)
  2. Pre-prime what I can (or choose to), tape off sections that will be glued and screwed
  3. Assemble with glue and screws
  4. Plug/fill holes and spot sand to 220
  5. Finish (spot) priming
  6. Put on the finish paint (2x)

The results will speak for itself once it's in the projects gallery. Hope it will be soon since the stool is a birthday present to be delivered in mid-April.
 
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