How To Mix Thinset For Tile in Small Batches to the Perfect Consistency

In the video above and the step-by-step article below, you’re going to learn everything you need to know about mixing thinset mortar for tile, from how to mix small batches to how to mix thinset for wall tile. I’ll also mention how much to mix on your first batch.

First, we’ll start with a list of tools and then on to the step-by-step instructions.

Tools and Supplies:

• Five-gallon buckets (x3)
• 1-3 quart plastic measuring containers (x2)
• Mixing Paddle
• Power Drill or Mixer
• Gloves
• Safety Glasses
• Dust Respirator
• Digital Scale (optional)

Step 1: Add Water To the Mixing Bucket

Always add the water before the thinset. Read the back of the thinset bag to see how much water you need for the entire bag. Then, figure out how much thin-set to mix, so you have enough for about twenty square feet of tile to start with for your first time.

The thinset I’m using in the video above said to use 5.5-6.5 quarts of water for the entire 50 lb bag. But that’s way too much thin-set to use at once, so I decided to start with 1 quart of water (about one-fifth of the bag), which is an easily manageable amount.

You never want to mix an entire bag on your first time because the thinset will likely harden before you have time to put it all on. So, start with enough thinset to cover about 20 sq. feet, then adjust from there on your next batch. Usually, it will say on the back of the thinset bag how much sq. footage it will cover given different trowel sizes, so you can calculate how much based on that.

Step 2: Add Thinset And Mix To Desired Consistency

There are two ways to do this. You can measure it out perfectly and even get out a scale to weigh out the perfect amount of thinset to water. This is great because it’s accurate and isn’t prone to user error. But, it requires you to have a scale laying around and do some math to figure out how many pounds of thinset per quart of water.

The second way is to add thinset and mix until you reach the desired consistency (similar to peanut butter). It doesn’t have to be perfect. If it’s a little runny, it will still work. If it’s a little thicker, it can still work as well. You’ll know that it’s too runny if it won’t hold a notch when you trowel it on the wall or floor, and you’ll know it’s too thick if it doesn’t easily stick to the substrate you’re applying it to.

Step 3: Continue Mixing For Time Specified On The Bag

Every thinset is slightly different, so you’ll want to follow the directions on your bag of thinset. Usually, it will tell you to mix for about 2-3 minutes using a power mixer at a slow rpm. If you don’t have a mixer, you can also use a power drill, but you will not want to do this by hand.

A power mixer is a great tool to have here, but it’s not necessary. You can also use a power drill, although this is hard on drills. Just make sure to set your drill to the slower setting, so you don’t mix too fast. If you’re using a variable speed drill with only one setting, then you’ll have to hold the trigger halfway to avoid spinning too fast.

Step 4: Let it Slake for 10 Minutes

Basically, you will leave it alone for about ten minutes so the water can start combining with the thinset and the chemical reactions can start taking place.

I would avoid letting it sit in the sun, though, unless you want the thinset to harden faster than normal and don’t need as much working time to apply it.

Step 5: Mix again for 2-5 Minutes

After the thinset has completed slaking, it will probably thicken up just a bit, but it will thin back up to a workable consistency once you start mixing.

NEVER add water after the slaking period. It can weaken the thinset mortar, so it isn’t as strong once cured. That’s obviously not good because you want your tile to last a long time and be durable. Make sure to dial in the right consistency during the first mixing stage.

Step 6: Application

Now you’re ready to use a trowel to apply the thinset. The working time before it hardens varies depending on a few things. The first is the temperature. The hotter the temperature, the faster the thinset will “set.” Cooler temperatures could easily double working time when compared to hot weather. Also, the amount of thinset you have mixed seems to change the rate that it sets. Smaller amounts tend to set faster because more of it is exposed to direct air relative to the total mass of the thinset. Larger batches will set slightly slower, but I’d still recommend starting with smaller batches until you get the hang of things.

You can increase the working time by remixing the thinset a couple of times while applying it. But this will only get you so far, and you’ll start to notice thinset hardening on your tools. That’s when you’ll want to clean your tools and whip up a new batch.

Obviously, avoid wasting thinset if you can, but understand that some waste is normal during this learning process. As you work with it more, you’ll get faster and more efficient while mixing and applying thinset. 

If you found this helpful, you’ll also enjoy How to tile shower and bathtub walls – The ultimate guide.