Paint "bumping up" over areas where filler used

[JonHeath]

Hey all,

I've been attemping to repair some cracks in a wall (small cracks in plaster caused by building works movement). I've cut out the cracks in a "V" shape and used gyproc easi-fill to fill. This is a product I've used before with success.

Anyway after sanding down to a nice smooth surface I'm having issues when repainting.

The paint is sticking to the area where the filler is more than the painted wall either side. This is resulting in a bump where the filler is. I've sanded it all back down and tried again with watered down paint, but again it is still bumping up.

The original paint on this wall is Dulux Diamond White. Not sure if this is contributing to the problem. I've tried watering down the Diamond White and also watering down a standard white paint, but neither went well and I still had bumping.

I've sanded it down again and I'm ready to paint. Other than watering down even more, I'm not sure what I can do different this time. Advice greatly received!

Thanks
Jon

 

[Nige F]

try a small tin of Zinsser B I N ( or a spray can of it ) cover the fillings, then paint . If you use a brush - get a cheap one and chuck it

 

[darkan9el]

Have you considered you may not have sanded enough, Paint will dry to micron's thick (a Micron is one millionth of a metre) so I doubt the paint is making the bump and by now the filler should be well and truly primed so no matting (area looks a different tone of the colour or looks dull compared to the surrounding area) when looking down the wall should occur.

Take a few pics and upload.

this is for Crown Trade Vinyl Matt.
Wet Film Thickness: 59 micrometres at 17m2 per litre
Dry Film Thickness: 17 micrometres at 17m2 per litre.

 

[opps]

try a small tin of Zinsser B I N ( or a spray can of it ) cover the fillings, then paint . If you use a brush - get a cheap one and chuck it

Or use a decent brush and clean it with household ammonia. Agitate the brush in a pot full of household ammonia. After, rinse the brush with water. No residue will be left in the sink/basin.

Overnight the ammonia will evaporate off and the pot will be little more than water with white dust in the bottom. You can then pour that down the sink and rinse the pot for future use.

Ammonia is an alkali, rather than simply diluting the shelac (as would be the case with meths), it breaks it down.

It even works with BIN brushes that have gone hard, albeit much slower.

 

[JonHeath]

Thought I'd post a quick message to close this out.

@darkan9el Yes it was sanded enough. If you closed your eyes and ran your fingers over these areas you wouldn't be able to tell it had been filled and sanded at all. I've done this sort of thing many times.

@Nige F Many thanks for the advise to use Zinsser BIN. I picked a 400ml spray can of it up. I did a couple of layers of this stuff before painting over and that has done the trick.