White gloss paint not fully set

[Lobster]

I recently painted some new MDF over the fast two weeks, (primer/undercoat/white gloss) finishing last weekend; all looks fine and the gloss was (apparently) dry overnight.

I'm aware that it's best not to subject fresh paintwork to undue knocks and wear for a decent while after it's apparently dry, but after a full week (indoors) it's clear that horizontal surfaces are not yet able to properly withstand stuff being stood on the, - eg a 1 kg object I stood on a surface last night was definitely slightly adherent this morning and has left a slight and I think permanent mark when removed.

The gloss was brand-new Dulux and well-stirred before use; I forget the undercoat brand but again certainly well stirred, and definitely bone dry (and sandable) before I put the gloss on.

I don't ever recall this being such a problem before - is it normal?

David

[TheOldFellow]

Temperature? If it's too cold the volatiles will not boil off properly, typically anything below 10C might cause this. Leave it longer and warm it up?

R.

[Lobster]

OK, maybe... it's been in an indoor bedroom with the radiator switched off so not particularly warm. Room is back in habitation as of today so maybe a day or so withe the heating on will sort it?

David

[stuart noble]

Sounds like maybe too much was applied in one coat, and solvents got trapped below the surface. I've had this happen on mdf. Something to do with the face of the board not being very absorbent I think.

[John]

Can the solvents get trapped in by having something stood on it - and this could cause softening - Just a thought..................

[A.Lee]

It's new paint formulations. I was talking about this in the pub today. I painted a door last week. The finish was bloody awful, with brush strokes all over it. It was still tacky on the edges after 24 hours, in a heated bedroom.My uncle, who is a full time painter says they are having the same trouble at work, paints which used to be good are not now that the formulations are changing for lower emissions. They used Dulux Trade new work gloss in a house, it was looking good a hour after painting. Another hour later, there were runs all over the door, with the paint still liquid, not even slightly tacky. He reckons all the makers are having the same trouble in getting the mix right to meet emissions regs, as well as giving a good finish and easy to use. Alan.

[Lobster]

Wouldn't be the case here, anyway; the vast majority of the area has been 'naked' all along; it was just one item left on the surface overnight which alerted me to the issue.

Thanks David

[Lobster]

Interesting. I put the can of paint away in the garage earlier today and although the lid's been sealed for a week, I still managed to come away with a white smear of paint on my hand.

David

[Steve Walker]

Yeah, in my experience it takes months before new gloss can handle a heavy ornament on a window-sill

[Steve Walker]

Are paint manufacturers forced to reduce volatile thinners, or do they just think the consumer market wants to see it?

Personally I couldn't care two hoots if it's 97.3% volatile - I rarely paint, and when I do I want a good job of it. The emissions from a year of drying paint in my home are probably less than a week of car use, it seems trivial and not worth compromising quality for.

[Phil Jessop]

You have to keep your eye on the ball ...

[PeterC]

About a month ago, Wickes had various paints at v. low prices (£2 - £3/li) at Personally I couldn't care two hoots if it's 97.3% volatile - I rarely

It'd be very thin paint! But yes, with all the prep. and other work, getting a useless finish is bloody annoying.

Are the manufacturers going to get it right, I wonder - and don't they test paints before inflicting them on us?

[stuart noble]

ISTR in Scandinavia they started phasing out solvents at least 20 years ago. Maybe they've made some progress by now. AFAIK there is still no water based gloss that doesn't look and behave like a sheet of clingfilm. Harder acrylics exist but they need high temperatures and a controlled environment to cure properly. Can't see the problem going away any time soon.

[Andy Dingley]

Worse than that, if you're cycling the temperature you'll cook the surface off (a brief warm daylight period) and make it near impermeable, but the layer beneath is still wet. That takes even longer than cure.

I wouldn't walk on it until Easter.

[PeterC]

I might stock up this year, then.

BTW, just 'rescued' ~2li of water-based gloss that came from B&Q about 20 years ago. Had to declag the surface, tranfer to a new container (why are the cans so corrodable?) and mix in some water. This am, painted a door frame and the start was touch-dry by the time I'd finished. Not as smooth as oil-based gloss - but a lot cheaper than buying new stuff that could be worse.

[stuart noble]

Same with pva. Stick a screw in the top of your wood glue (because you've lost the little plastic plug) and it corrodes something horrid.

and mix in some water.

I actually prefer it for some things where solvent based yellows over time, but IME it has absolutely no resistance to knocks or abrasion.

[PeterC]

My current containers for glue have plastic, screw-down nozzles; otherwise I use st. st. screws.

This stuff was put on the 2 handrails on the stairs about 20 years ago and is still OK (but no one else in the house, so not chewed etc.).

[Rod]

Blame Andrew Lloyd Webber and his Phantom sequel - Paint Never Dries (or something like that). :-)