So, I've been messing around with trying to paint some repaired plaster wall, with mixed results and cracking paint. I think I have a working solution now after 2 weeks, touch wood, but was hoping to get some advise what I did wrong in terms of the painting prep.
For your amusement, the story is thus. Probably should go under DIY disasters.
So, was painting downstairs toilet. Took off mirror. Painted room, let dry. Put on mirror. Overtightened screws. Mirror shattered. The bad luck commenced. New mirror purchased immediatey on wife instruction. Drilled 4 holes for mirror using template. 2 of the 4 holes hit pebbles in the breeze block, tried putting in shorter screw in wall plug, took chunk out of wall. Drilled additional 8 pilot holes until found acceptable locations that did not hit pebbles. Now had like 12 holes of which 4 were needed and two were super-size. Had flexible polyfilla to hand. Filled holes. Attemped to sand. Turns out this product does not go hard. Removed flexy polyfiller, holes now larger. Bought standard polyfiller. Filled holes, sanded. Painted filled areas and surrounding area with fairly thick layer of emulsion. Emulsion peeled off, when I picked at it it took all the paint underneath off with it even though paint was 5 years old! Used screwdriver to scrape off peeling emulsion. D'oh, managed to scratch plaster layer. Bought polyskim (basically paint on thinned polyfiller) to smooth now 2 ft2 area of wall and sanded it until perfectly smooth to touch.
So now I start again with a white polyfillered area in the middle of the previously painted wall and this is the bit that really confused me. To avoid it peeling again, I bought and applied a single coat of Dulux Plaster Sealer, which starts off blue and is supposed to finish up white after 24 hr drying time. I left it 24 hrs, it felt dry even though very slightly blue still, which I put down to being over white polyfiller.
I applied a thin layer of Dulux White Matt Emulsion. Let it dry for 6 hours (says 4 on in), and noted it had cracked and crazed after 1 hour (not peeled this time), particularly where the polyfiller met the old paint at the edge of the repaired patch, but also in vertical lines (I painted the polyskim on vertically). Sanded it a tiny bit to get it smooth, put another coat on as thin as I could. Same result with vertical cracks. Sanded it again. Put a very thick coat on to see if helped. Cracked even more this time!
Sanded it, then I tried watering down the paint by 10% and putting another coat on. Same result. Yes I was getting annoyed by this point and my wife was close to divorcing me.
Then I tried two different things. Sanded it again. I put on a thin layer of Dulux bathroom & kitchen (also water based) paint instead of the standard matt paint. I also left the door open to keep the room warmer, as the wall felt cold to the touch. If I was to guess the temperature of the wall by touch, I would say 10 degC. This is a small toilet room that is on the party wall of my semi and unheated.
Aha! It is now okay! So I put the standard matt paint over the top of the bathroom paint so it matches rest of wall, though I may decide to just use the bathroom paint throughout if it is more resilient.
I was just wondering why this happened. I mean in terms of preping and painting the plaster/polyskim. Could it be because it was too cold in there? Either causing the paint to craze or the sealer coat to not dry properly? The paint layers were certainly dry.
Or perhaps due to the sealer I used? Or should I have used a sealer, followed by an undercoat? Or a special primer? What are you supposed to use over this polyskim product? It says to prime the surface, the diy store recommended a plaster sealer.
Do you think the bathroom paint helped somehow? Could I use this as an undercoat in the future?
What fun we have...
For your amusement, the story is thus. Probably should go under DIY disasters.
So, was painting downstairs toilet. Took off mirror. Painted room, let dry. Put on mirror. Overtightened screws. Mirror shattered. The bad luck commenced. New mirror purchased immediatey on wife instruction. Drilled 4 holes for mirror using template. 2 of the 4 holes hit pebbles in the breeze block, tried putting in shorter screw in wall plug, took chunk out of wall. Drilled additional 8 pilot holes until found acceptable locations that did not hit pebbles. Now had like 12 holes of which 4 were needed and two were super-size. Had flexible polyfilla to hand. Filled holes. Attemped to sand. Turns out this product does not go hard. Removed flexy polyfiller, holes now larger. Bought standard polyfiller. Filled holes, sanded. Painted filled areas and surrounding area with fairly thick layer of emulsion. Emulsion peeled off, when I picked at it it took all the paint underneath off with it even though paint was 5 years old! Used screwdriver to scrape off peeling emulsion. D'oh, managed to scratch plaster layer. Bought polyskim (basically paint on thinned polyfiller) to smooth now 2 ft2 area of wall and sanded it until perfectly smooth to touch.
So now I start again with a white polyfillered area in the middle of the previously painted wall and this is the bit that really confused me. To avoid it peeling again, I bought and applied a single coat of Dulux Plaster Sealer, which starts off blue and is supposed to finish up white after 24 hr drying time. I left it 24 hrs, it felt dry even though very slightly blue still, which I put down to being over white polyfiller.
I applied a thin layer of Dulux White Matt Emulsion. Let it dry for 6 hours (says 4 on in), and noted it had cracked and crazed after 1 hour (not peeled this time), particularly where the polyfiller met the old paint at the edge of the repaired patch, but also in vertical lines (I painted the polyskim on vertically). Sanded it a tiny bit to get it smooth, put another coat on as thin as I could. Same result with vertical cracks. Sanded it again. Put a very thick coat on to see if helped. Cracked even more this time!
Sanded it, then I tried watering down the paint by 10% and putting another coat on. Same result. Yes I was getting annoyed by this point and my wife was close to divorcing me.
Then I tried two different things. Sanded it again. I put on a thin layer of Dulux bathroom & kitchen (also water based) paint instead of the standard matt paint. I also left the door open to keep the room warmer, as the wall felt cold to the touch. If I was to guess the temperature of the wall by touch, I would say 10 degC. This is a small toilet room that is on the party wall of my semi and unheated.
Aha! It is now okay! So I put the standard matt paint over the top of the bathroom paint so it matches rest of wall, though I may decide to just use the bathroom paint throughout if it is more resilient.
I was just wondering why this happened. I mean in terms of preping and painting the plaster/polyskim. Could it be because it was too cold in there? Either causing the paint to craze or the sealer coat to not dry properly? The paint layers were certainly dry.
Or perhaps due to the sealer I used? Or should I have used a sealer, followed by an undercoat? Or a special primer? What are you supposed to use over this polyskim product? It says to prime the surface, the diy store recommended a plaster sealer.
Do you think the bathroom paint helped somehow? Could I use this as an undercoat in the future?
What fun we have...
