What grit sandpaper????

[5oysterman2]

Morning peeps.

Finished glossing skirting, frames & doors now, but still got a few nibs that need removing.

What grit sandpaper to use & how best to go about the task without scratching paintwork. Many thanks

 

[Munroast]

the whole idea of sandpaper is to scratch the surface

by 'a few nibs' are we talking about bits of dirt/grit in the paint that has left a tiny bump ?

 

[5oysterman2]

the whole idea of sandpaper is to scratch the surface

by 'a few nibs' are we talking about bits of dirt/grit in the paint that has left a tiny bump ?

Bits of grit/dirt left

 

[opps]

Water or oil based paint?

I would use 180g or 240g Abranet mesh. Not cheap but great for soft paint.

 

[Munroast]

while the paint is still soft (it is for week or so) just pick the grit out with a sharp blade and prees the paint back into place with the back of your nail - I have done this a couple of times and it worked better than i thought

or just polish it all up with some wax

 

[5oysterman2]

Water or oil based paint?

I would use 180g or 240g Abranet mesh. Not cheap but great for soft paint.

Water based

 

[opps]

Water based

Go for a 240 grit then.

A cheaper version will something like the following.

https://www.toolchimp.co.uk/vaunt-x-115mm-x-5m-240-grit-mesh-net-sanding-roll

I haven't use the above though.

I recommended a flexible mesh because it is less likely to clog. When abrasives clog, the clogs can rip the surface of the paint.

You could try a stearate coated silicone carbide paper. The stearate coating reduces the friction when sanding. Typically, they are grey in colour and the backing paper is quite/very thin. I would avoid aluminium oxide papers (typically red/green/yellow). The backing paper is too rigid. Wet and dry paper might work if you are very gentle, but if using it dry, again there is the risk of cloging.

Waterbased paints are a mare to sand, even when cured. If the grit number is too low, the paint will shear off the surface or it will clog the abrasive.

In general, when sanding existing paint work try to go no finer than 360 grit. Any finer, you risk polishing the paint and reducing adhesion. That said, if the paint is relatively new, you might "get away" with it.

 

[5oysterman2]

Go for a 240 grit then.

A cheaper version will something like the following.

https://www.toolchimp.co.uk/vaunt-x-115mm-x-5m-240-grit-mesh-net-sanding-roll

I haven't use the above though.

I recommended a flexible mesh because it is less likely to clog. When abrasives clog, the clogs can rip the surface of the paint.

You could try a stearate coated silicone carbide paper. The stearate coating reduces the friction when sanding. Typically, they are grey in colour and the backing paper is quite/very thin. I would avoid aluminium oxide papers (typically red/green/yellow). The backing paper is too rigid. Wet and dry paper might work if you are very gentle, but if using it dry, again there is the risk of cloging.

Waterbased paints are a mare to sand, even when cured. If the grit number is too low, the paint will shear off the surface or it will clog the abrasive.

In general, when sanding existing paint work try to go no finer than 360 grit. Any finer, you risk polishing the paint and reducing adhesion. That said, if the paint is relatively new, you might "get away" with it.

Cheers opps, you learn something every day.

Being an amateur, i assumed when sanding for the topcoat the finer the paper the better. Obviously not lol.

 

[opps]

Cheers opps, you learn something every day.

Being an amateur, i assumed when sanding for the topcoat the finer the paper the better. Obviously not lol.

I used to think the same thing too. Many years ago I was spraying a cabinet with 2 part paint. The finish felt like someone had sprinkled it with an incredibly fine sand. I was planning to sand it with 500g on my random orbital sander but the paint manufacturer's technical help warned me that doing so might polish the paint and reduce the adhesion of the next coat. From that point forward I stopped using 400+ grit.

Absent using a microscope, you should not be able to see scratch marks from 240- 360 grit when repainting (assuming that the paint doesn't clog the paper and scratch/rip the paint significantly).