Choosing the right equipment, preparing the wall meticulously and buying a decent plastering trowel are all important, but the key to creating perfect plaster for a perfect finish is in the mixing.
Mixing Plaster for Perfection
If you want to mix plaster for the perfect finish, then you’ll need to choose the right paddle for your mixer. You need a paddle that won’t suck in air, as plaster should never have air bubbles in it. Then select a paddle that cope with the amount of plaster you need to mix, whether that’s render or a skim coat.
You’ll also need to use scrupulously clean water. And remember, only an amateur mixes plaster by hand.
Pick Your Paddle
The paddle diameter should be anywhere between a third and a half of that of the mixing bucket, and you should use a mixer or drill with sufficient power to really churn the mix thoroughly. The paddle needs to be able to fit in the bucket yet be able to move into all corners of it to get a really smooth result.
There are several styles of mixing paddle out there, all of which give a slightly different result. For example, a semi-rounded head design looks and works like a potato masher, mashing the plaster through the head of the mixing paddle for a smooth and lump-free result. The most common style of mixing paddle is the twin propeller design, which uses a parallel mix action to blend the plaster and water with very little splash.
Three-blade spiral paddles have two helix blades and a cross blade and are best used with high-torque drills and mixers. The plaster is continually pulled from the bottom to the top to create a smooth and even mixture. The other most common type of paddle is the screw spiral either with or without a rim, which again lifts the mix from the bottom to the top and is ideal for heavier mortars and renders. Using a rimmed paddle will protect the container in which you’re mixing your plaster from damage.
Create the Perfect Mix with a Plaster Mixer Mixing plaster isn’t difficult, but there are some good reasons why you need to use a good-quality plaster mixer. First, if you’re plastering all day, mixing up a lot of plaster can be tiring and time-consuming. A good mixer and paddle combo can also mix the plaster far more thoroughly than is possible by hand, creating a smooth and creamy lump-free mix for a really excellent result. A plastering mixer will get into all the corners of your mixing container and leave no lumps or unmixed material behind.
Step by Step to Perfect Plaster
Plaster and water are mixed in a 50/50 ratio, so for one bucket of plaster you’ll need half a bucket of fresh clean water. Pour this into your thoroughly clean mixing container – a bucket is fine.
Now add approximately half the total amount of plaster you’ll be using, pouring it straight into the water. This is where your plastering mixer comes in. Plunge it immediately into the mix and start churning – don’t wait, or you’ll get lumps that you’ll struggle to get rid of even with the most powerful mixer.
Start on a low speed to prevent splashes – or use a twin-propeller paddle – and make sure you mix in both directions for optimum results. Raise the paddle gently up and down to make sure you really get everything thoroughly mixed.
Once you have a smooth and creamy mixture, add half the remaining plaster and blend in thoroughly using the mixer, making sure you’ve mixed in all the dry plaster. Now use your plastering trowel – if you’re thinking about buying plastering trowels, consider buying a trowel that has already been worn in – and test the consistency. The mix should stick to a level trowel without running off.
If it’s too sloppy, slowly mix in additional handfuls of plaster until everything is the consistency of melting ice cream, but be careful not to over-mix. A good rule of thumb is to make your mix slightly thicker for ceilings and slightly wetter for walls, but the right consistency for you to work with will come down to personal taste.
Finally, wash your equipment thoroughly before the plaster has a chance to harden, as that can ruin your paddle and any traces of plaster in your bucket can contaminate a second mix and make it unusable.
And that’s all there is to it. As you can see, using the right paddle with a powerful plastering mixer or drill will make creating even the most heavy-duty mix a breeze, leaving you to focus on creating the perfect finish