Dust

[cocoots100]

Hi There

when painting window sills with an oil based system, I always get the odd speck of dust which ends up spoiling the finish everytime.
The paint is strained, brushes are clean, kettle is clean, window sill is wiped - yet the little blighters still appear.

Would like some advice on how to get that perfect finish. Will a tack cloth help? Never used one - would like to hear if this helps and some general advice.
Cheers

 

[Nestor_Kelebay]

Unfortunately, we're relying on you to tell us exactly what the problem is so that we can give you some advice on how to solve it.

If the problem is caused by dust, then it's simply a matter of covering the paint so that the dust doesn't get on it.

Are you 100% sure that the problems you get on the paint are caused by dust?

I'm wondering if they could instead by due to particles of dried up paint from deep in the bristles of the brush that fall out when using the brush.

You need to keep in mind that a good quality oil based paint will have a solids content of 50 percent or better. That means that only 50 percent or better of what's in the can will remain behind as a solid, and the rest will evaporate as the paint dries. That also means that as the paint film dries, it's thickness will shrink to 50 percent or better of what the wet paint film thickness was.

Because of that shrinkage in film thickness in the paint as it dries, is it possible that small particles of dried paint from the brush or the can are immersed in the wet film thickness, but stand out and become apparant as that paint dries and it shrinks in thickness as the solvents evaporate?

PS: Are these interior or exterior window sills that you're painting with oil based paint? And are the window sills made of wood or some other material? Finally, if these are exterior wood sills, are you finding that the paint peels off in only 2 or 3 years?

 

[Zampa]

You wont need a tac cloth...a damp rag followed by the palm of your hand should be fine...

As Nester said crud in the brush or the paint is one of the most common causes of bittiness..if you using oil based try giving the brush a sloosh out in white spirit first then spin the brush between the palms of your hands over a bucket to remove the access spirit and hopefully any bits.

Dont put the brush down after...keep it in your hand.

Make sure you dust off the rim of the lid when you open the can...lots of crap falls in the paint from the lids...wipe around the rim of the can with a cloth...to remove bits of old paint that may be stuck to the edge.

Another couple of things you can do which may help...dampen the floor around where your working if possible to stop dust rising...and roll your the sleeve up of the arm your painting with...youl be surprised how many fibres come off of clothes.

Staining..use a pair of old tights or stocking they are ideal..not fishnets though!

Crud tends to collect in the corners of window cills...check them before you start.

 

[skybluescooby]

you could always use a takrag prior to painting to wipe up all the minute specs of dust but otherwise follow zampas advice