Mixing plaster is as much of an art as it is a science. It’s important to keep a consistent mix from one batch to the next and this isn’t always easy to accomplish. One of the most common mistakes people make when creating plaster mixes is to lose track of how much sand has been put into the mixer. Have you ever mixed plaster with a bunch of folks helping you? If so, you know exactly what I mean.
Picture this: you’re using a 5 gallon bucket to place sand into the mixer. You need 4 buckets of sand for every bag of lime you add to the mixer. Your helpful friends are filling up the bucket as fast as you empty it and you guys are totally cruising through the mixing process. Suddenly you ask your friend “is that 3 or 4 buckets?” In return you get what a friend of mine calls a “goat face,” a look of complete disconnect. Now you retrace your steps to try and figure out how much sand is in the mix. You look at the plaster tumbling on the paddles in hopes of recognizing the texture of the mix. IN truth, neither of you have any clue how much sand is in the mixer. There’s a better way.
Instead of using one bucket, use 4. Three buckets should be the same color and the last bucket a different color. This way know if you’ve made it to the end of a load. For example, when I mix plaster, I can usually fit 3 bags of lime in the mixer at a time which means I need 12 buckets of sand. Counting those out one by one would be hard to track, so I use the 4 buckets. I put in three white buckets of sand and then an orange one (you could always use another white bucket and just pray paint it or wrap it with tape). As soon as I see that orange bucket go by, I know I’m at the end of a run. Now my helper can fill all 4 buckets again while I add the bag of lime and we’re ready for the next grouping. It’s easy!