Spraying pliolite masonry paint is something that a lot of decorators are dubious about, but if you’re competent with an airless sprayer, then it’s relatively easy. I spend a lot of my summer spraying masonry.
The area where I live has a lot of pebble dash and rough cast render, which a lot of local decorators tend to avoid. I don’t, I love it, and it doesn’t bother me whether I’m spraying water or pliolite based paint either.
I thought I’d put together a simple blog to help anyone thinking about spraying pliolite. I’ll cover some of the very basic points and help you avoid some of the pitfalls. I hope you find it useful.
Preparing the Property
Well, your prep to the masonry should be the same whether you’re spraying or using a brush and roller. Loose paint should be removed, unstable or chalky surfaces should be stabilised, alga should be treated with fungicidal wash. You get the idea.
You will paint your trim (soffits, facias, doors etc) after spraying the masonry with pliolite, however the prep should be done to every surface before you even think about doing any painting. Otherwise, you’ll be sanding and scraping facia boards, only for the dust to dirty your newly painted render.
Go over the top with sheeting and covering any windows or doors. On this particular property, there are wall lights and plastic soffits, all of which don’t just need covering, but completely sealing up. So, go round every little bit of plastic or paper sheeting with a good quality tape. If you miss even a centimetre, the spray is likely to blast through and make a mess of the thing you were trying to cover.
Setting up your Sprayer
The first thing I do when I’m going to spray pliolite is change the filters, then circulate some white spirit through my airless. After all, water and oil do not mix and that litre or so of white spirit in your hose will come in useful in a second.
I dilute my pliolite by around 15%, which makes it both easier to spray and easier to work into every crevices on rough cast or pebble dash. My sprayer (Titan 460e) doesn’t have a hopper, so I mix my paint in a 15L bucket which I then use as a reservoir to feed my machine. When priming my hose with the paint, I empty the white spirit from my hose back into my bucket. I do not mix this in with my paint!! Pliolite skins over very quickly, but having a layer of white spirit on top will prevent this completely.
Other than that, just keep the piston topped up with lube and have a kettle of white spirit handy to rest your gun in when not in use. This will prevent any build up of pliolite around your tip.
As soon as you mention spraying masonry paint on any of the good decorating forums on Facebook, you always have half a dozen decorators perk up with warnings, or tales of mass damage due to overspray. I won’t say overspray is a myth because I’m sure it does catch the odd sprayer out, but I believe if you follow a couple of simple steps, you’re in less danger than if you were using a brush and roller. You should still be careful. Overspray from water-based masonry paint generally falls as dry dust. Overspray from pliolite-based masonry paint may not dry whilst airborne, so more likely to damage cars etc.
Firstly, let’s talk about your dust sheets. If you’re painting a wall with external corners, always have a couple of sheets on the other side of your external corner. This is where overspray is most likely to happen.
Also, if you’re protecting say a driveway which starts at the bottom of the wall you’re painting, pin your dustsheets down next to the wall. I use scaffolding boards, but bricks will do the job. This is to prevent the power of the spray lifting the sheets and paint vortexing underneath.
The next thing to remember is keep your gun pointing directly at the wall and stay close. No arching up or down at the end of a pass, and certainly not left or right. Every bit of material that comes out of your spray gun needs to hit the wall and not projected away from the object you’re trying to paint. Keep your pressure low so paint isn’t bouncing of the wall and hitting your hand.
The only other things to remember are don’t overreach, as you’ll end up squirting material in the wrong direction, and spray inwards on the external corners. The corners, or tops of the walls are where you need to be particularly careful really. If your spray fan overlaps an external corner, then some of your paint is going to be blasted into the air.
It’s simple isn’t it. I’ve given you three or four things to think about when spraying masonry to cut down on overspray. Do them and you’re basically safe. Common sense comes into play too of course; ask your clients to move any cars that are on the drive and don’t spray in windy conditions.
When to Backroll
I rarely backroll when spraying masonry paint. Maybe if it’s the roughest rough cast render in the world, or unpainted pebble dash, but that’s about it. Even then, the sprayer will force material deep into the wall, flooding pretty much every gap. That’s what you’re aiming for anyway, which is another reason to have your spray gun as close as possible to the wall.
If you do need a roller, it is normally because you’ve flooded the wall a bit too much and need to spread the paint out as you go. Spraying and backrolling is a 2-man job really. There are jet rollers available, but I haven’t used one before so I can’t comment on how useful they are for this type of painting.
95% of the time you will not need to backroll. Just get the paint on, flood the gaps and if you need to, cross hatch to get every angle. I generally use tip size 515 for any rough render and 517 for the smoother stuff.
Cleaning your sprayer, as you can imagine, is crucially important if you’ve been using pliolite. If I’m using pliolite the next day I’ll just run some white spirit through the machine, drop the gun in white spirit, and job’s a good ‘un. At the end of the job, it’s good to be more thorough. Same process as if you’ve been spraying water-based paint really, but you use turps or white spirit instead of water.
Clean the intake and circulation pipe whilst submerged in white spirit, scrap your filters, then run white spirit through until it’s flowing clean. You can recycle the white spirit by allowing it to settle overnight, then tipping the clean white spirit back into a bottle.
I spray white spirit though the tip to clean that too, then I clean the gun and the tip in thinners. Sometimes I clean the intake pipe with thinners too, it just depends on whether it needs it.
After that, get a few buckets of clean warm water through your sprayer, then you’re good to go.
I know most decorators wouldn’t dare spray pliolite-based masonry paint, but providing you’re experienced with an airless and you follow the steps outlined in this blog, you shouldn’t worry too much. However, there is always a risk. The last thing I want is to encourage an inexperienced sprayer to ‘have a go’, if there’s a chance you can cause damage to someone’s property. Spraying water-based masonry paint is a lot safter.