Sand/de-nib between coats of on exterior woodwork?

[DIYNotIan]

Hi all

I am currently doing up my external wooden windows. I have used Zinsser Bullseye 123 as the primer and will be using Eico Alterior Eggshell for the topcoats:

http://eico.co.uk/products/eico-alterior-eggshell-1l/

Should I lightly sand / de-nib the primer before painting the first topcoat? And should I sand/de-nib between topcoats?

Aside form general advise on that, what would be very helpful to know is what purpose the sanding/de-nibbing serves? Is it purely to get a better and smoother finish? Or does it make for a longer lasting job? In other words, is it purely aesthetics or does it serve practical purposes too?

Many thanks

Max

 

[misterhelpful]

De-nibbing is always best for a professional finish. It does somewhat help coats adhere, but fresh paint adheres to itself relatively well anyway. Obnce a coat has fully cured (several days for water based, several weeks for oils) then sanding to improve adhesion may be required.
I use around 240-300 grit between primer and first coat, then a very fine (400-600 grit) wet and dry paper (silicone carbide) before the final coat.

 

[DIYNotIan]

Thanks for the reply - much appreciated. I'm not so worried about a smooth finish, I just want the paint job to last as long as possible. Unfortunately it will be a bit more than a few days between coats of topcoat, so maybe I will give a light sand. But if I can get away without a de-nib then without affecting the performance then that's what I'll do.... Hmmmm.....

Cheers