Thinset mortar comes premade or in a dry mix and is used to adhere tiles to floors or walls. For the true do-it-yourselfer who wants to control every aspect of his remodel, thinset dry mix allows you to make your own thinset to your desired consistency. However, you have to be careful of over- or under-watering the mortar. The strength of the mortar is proportional to the amount of water in the mix. Too dry and the tiles will not stick to the floor; too wet and the tiles will pop off as the floor ages.
Gather three clean 5-gal. buckets for mixing.
Fill one bucket with water for cleaning your tools and one with the manufacturer's recommended amount of water for the thinset mortar.
Add half the manufacture-recommended amount of water to the third bucket.
Add all the thinset dry mix to the bucket. Pour carefully and as near the bucket as possible to avoid creating clouds of mortar dust.
Pour one-quarter of the remaining manufacturer's amount of water on top of the mortar mix.
Attach a mixing paddle to a 14-volt or higher electric drill. Do not use a battery-powered drill. Once the mortar begins to thicken, the motor will not be strong enough to mix the mortar.
Insert the mixing paddle to the bottom of the mortar bucket and start the drill on high speed. After you thoroughly incorporate the dry mix, increase the speed of the drill to mix the mortar.
Add the remaining water in small amounts as needed. The final consistency of the mortar should be like thick pudding or creamy peanut butter. If the mortar is thin enough to pour, you have added too much water and will need to add some dry mix to compensate. If the mortar is like chunky peanut butter or crumbles, you need to add more water.
Remove the paddle from the mortar and scrape off as much as possible with a trowel.
Insert the mixing paddle into the bucket containing the clean water and turn the drill on low speed to wash off the mortar. Do not delay. If the mortar dries on the paddle, it will be impossible to remove without damaging the paddle.