Grit Sizes For Sanding At Various Stages Of Painting ?

[WhiteVanJack]

Hi,

Would somebody please be able to provide some guidelines as to the grit sizes to use for various stages of painting.

Stage 1 - Bare wood stripped of paint with heat gun and sanded with 120 grit, next step is to prime with aluminium wood primer. Do I need to sand with a finer grit such as 180 before priming?

Stage 2 - Primed wood to be undercoated. Is 180 grit OK for a light sand of the primed coat or should I go finer to 240 grit?

Stage 3a - Undercoated ready for gloss. Is 180 grit OK for a light sand or should I go finer to 240 grit

Stage 3b - Old gloss paint, not removed but sanded with 120 grit to take off the gloss effect and provide a key. Do I need to sand with a finer grit such as 180 or 240 or is 120 OK?


Rgds
Jack

 

[dcdec]

It depends what type of abrasive paper you use.

I use silicon carbide because it keys and flats the paint, aluminium oxide tends to scratch and can affect the finish. I use aluminium oxide on heavy filling and then smooth it off with silicone carbide, i also use it on flaky paint which i want to remove, normally p90, dont think i ever use it on anything else. I rub paintwork down with 240 silicone carbide and then use a worn bit for between coat sanding. If i'm looking for a first class finish and the moneys in the job i wet abrade between coats and also wet abrade before a second coat of gloss and i use a medium grade (say 400) bearing in mind i think it goes up to around p3000.

 

[joe-90]

I'd agree with you Jack, I don't like grit too fine as you can fart about all day.