How To Keep Your Hands Clean When Using Thinset Mortar

Thinset Mortar is concrete with polymers added for enhanced strength and adhesive properties and is the recommended material for all outdoor and wet mosaics (pools, fountains, etc.). Unhardened thinset looks more or less like wet concrete, but it is sticky almost like honey or tar, and handling it for the first time can be a little intimidating. However, with some basic planning, you can eliminate a lot of the mess and all the stress.

One approach is to pre-mount your tiles on paper or mesh so that the final installation only involves trowels to spread thinset on a surface instead of placing individual tiles by hand into thinset.

But what if you want to mount individual tiles by hand and use thinset similar to how you use a convenient bottle of glue to make indoor mosaics?

Well, it doesn’t make sense to try to apply a small amount of thinset to the back of an individual tile similar to how people will sometimes apply glue to the back of a tile from a squeeze bottle. That approach continually contaminates the fingertips with thinset. Instead, it is more efficient and cleaner to spread a little bit of thinset over a small area of your surface and press tiles into that. Small trowels, old butter knives, palette knives and even popsicle sticks are useful for this.

These same spreading tools are also useful for pushing the tiles around and making slight adjustments in position, but invariably artists will use their fingertips for this purpose once they “get in the groove” and lose themselves in the creative flow. And then there are all the plops and spills and silly accidents like picking up the spreading tool from the wrong end.

The question becomes how do you keep your tools and hands clean without consuming a large amount of rags. Remember, this isn’t water or even glue that you are wiping off. It is concrete with sand it it. While you might be able to use the same rag all day when working with Weldbond or some other water-based glue, you can make a rag more of less unusable with just a few wipes of thinset.

Without a system, you will use up an astronomical amount of rags and still have dirty hands. It just isn’t possible to reach for rags randomly without eventually grabbing one that is already contaminated and smearing wet concrete across everything. And it is always the rag that looks perfectly clean that bites you! When the material in question is thinset, it only takes a pea-sized amount to make a big mess.

My Three Rag System

Mosaic and other crafts are more enjoyable and productive when you organize your workstation so that tools and materials are close to hand. This is doubly true when you are working with a messy material like thinset. You’ve got to set things up in a way that takes into account that you will frequently need to clean your hands and tools.

Here is how I use three rags in different ways to maximize the useful life of each rag:

  • Dirty Rag: a contaminated rag lying on the work surface near the art.
  • Wet rag: a rag is floating in a 2-gallon bucket half filled with water.
  • Dry Rag: a clean dry rag lying in the artist’s lap.

Dirty Rag

The dirty rag is placed directly on the mosaic or work table, right beside the place on the mosaic where I am currently mounting tiles. This is the rag used for wiping clumps of thinset from fingertips and tools. (Note that you should try to shake off large clumps of thinset into a garbage pail first.)

Wet Rag

The wet rag floats in a bucket half-filled with water. Hands and tools are dipped into the bucket to rinse them off. The wet rag stays in the bucket and is only there to provide something to rub against to help remove any last traces of concrete.

Dry Rag

The dry rag in the artist’s lap should only be used for drying hands and tools that are free of concrete and merely wet. Once the dry rag is contaminated just a little bit, it more or less has to be demoted to being used as the dirty rag. With that in mind, you have to be disciplined and resist the urge to grab it to wipe away spills and smears on the mosaic. For this reason, you should have a fourth rag for emergencies and use it only for that purpose.

Emergency Rag

In addition to the three rags used for cleaning and drying hands and tools, a fourth rag is needed for cleaning drops and smears on the mosaic itself. Of course, you should always try to get most of the material up using your trowel or spreading tool and use the emergency rag only for the residue so that it lasts longer. Once the emergency rag becomes too contaminated, it is demoted to being the new dirty rag.

Additional Materials and Tips

It takes a little practice to be able to lose yourself in your work and still be disciplined and conscious enough to not grab the first rag you come to when you make a mistake. That is why you should have a box of extra rags standing by. You should also have a bucket by your feet for quick disposal of contaminated rags.

Rinse Your Dirty Rags Outside

Remember to take a break and run outside to the garden hose and rinse the thinset from these rags before it hardens. These rags might be permanently stained, but they can be cleaned sufficiently to be as useful as new rags in the studio. If you are only an occasional artist, this need to reuse rags might not be such a big deal, but if you work with thinset on a regular basis, the amount of rags consumed can be significant. There will always be some that are past saving, so we try to salvage what we can.

Use a Garbage Pail

Another tip is to have an old garbage pail at your workstation so that you can throw old clumps of thinset into it instead your dirty rag bucket. I put scraps of cardboard and trash in my garbage pail to that I have something to wipe my spreading tool on. I try to use the garbage pail as much as possible to take pressure off my dirty rag.

Recycled Plastic Grocery Bags

Most artists tend to work until they can’t work any more, and that makes clean up all the more burdensome, especially when clean up involves wet concrete and requires some actual labor. This is when people are tempted to just grab all their contaminated rags and use them to wipe the left over thinset out of the mixing bucket and just throw them all away and be done. Again, this might be acceptable for an occasional artist, but it really isn’t very “green” or sustainable in a studio that frequently works with thinset.

The good news is that there is a readily available waste material that can be used as a disposable wipe for rubbing thinset off buckets and tools. Plastic grocery bags work very well for this and can be gathered for free in as large a quantity as needed.

Medical Examination Gloves

Thinset and grout contain portland cement and are mildly caustic. We wear disposable latex medical examination gloves when we work with thinset to keep it from drying out our skin.







10 responses to “How To Keep Your Hands Clean When Using Thinset Mortar”

  1. Eleanor Lauck Avatar
    Eleanor Lauck

    I’ve always done mosaics for fun & for gifts but now that I’m retired I’m excited about getting back into it full time. Your site is amazing & and now I’ve stumbled upon this area of info. In the past I could never find all the info I wanted & needed but now I can see such amazing possibilities for all that I want to create.
    Thank you for your website with all it’s content & product. And thank you for this blog (?). Hooray!!!
    Eleanor Lauck

  2. […] scrap. That way you can figure out how thickly to spread the thinset to avoid problems and practice keeping your hands clean while working with wet concrete. Otherwise your fingertips are likely to get wet concrete on objects that aren’t easily […]

  3. […] All that being said, if you want to learn how to do this professionally, or if you want to make absolutely certain that your projects last as long as possible, then you need to learn to use thinset, which isn’t that hard in my opinion. I wrote a page about how to use thinset mortar for mosaic artwork and a blog article about how to keep your hands clean when using mortar. […]

  4. […] I have written some instructions for using thinset mortar and some tips for keeping your hands and tools clean while working with thinset mortar. […]

  5. Linda Conner Avatar
    Linda Conner

    Just starting up a class with 4 women wanting to work with mosaics and found your site which is fabulous. It will become our mosaic bible!

  6. […] Thinset mortar should be used instead of adhesive for attaching the tile. A complete list of tools and materials for mixing thinset and for applying thinset is given in my instructions for using thinset mortar with glass tile. (Note the instructions were written for doing extremely detailed work, so I might make thinset sound much more difficult than it really is.) I have also written a page for how to keep your hands clean when using thinset. […]

  7. Kati Avatar

    As my daughter is fond of decorating cakes and left her piping bags lying around I got the idea to use disposable non-slip icing bags for ultimate thinset control. I fill the bag 3/4 full with prepared thinset, put a rubber band over the top and tie off the unfilled part of the bag as to stop the air from getting in, and dried thinset to spill out backwards. Then its time to cut the tip off, the wider the bigger string of thinset. Too small makes it hard to squeeze the bag. As the level of thinset declines one can use a clip (or a second rubberband) to seal the emptied bag off. The thinset will not set prematurely in the bag which makes it possible to work with the same batch for up to 8 hours while keeping the workspace clean. As I only have a small corner to use as studio it gives me longer time at mosaicking and less time spent cleaning. Saves a lot off rags and water too. I greatly appreciate your tips on studio lay out (and the one about netting the spout of the vacuum cleaner!), but while I long for a dedicated studio space the above will be my preferred thinset method. Kati

    1. Joe Moorman Avatar


      That is actually a great idea, and I have used it myself. I started putting the tips on the end of my grouting bag merely because the grouting bag holds more and is stronger, but the icing bag is actually ideal for smaller jobs and for people who work slower.


  8. Laria Avatar

    Hi. My son and I are preparing to mosaic a concrete bird bath that came with out house 17 years ago! Thank you for the well laid out instructions. I think since it is our first rodeo it would be best to layout the design on mesh prior to using the thinset (as you have suggested in the section about keeping hands clean). Can you provide instructions on the best way to do this? I assume we need to stick the tiles down to the mesh somehow, but it’s a little unclear and I want to get it right.

    1. Joe Moorman Avatar
      Joe Moorman

      Hi Laria,

      A birdbath is not right for fiberglass meshfiberglass mesh for two reasons: First, it is a curved surface. Second, the mesh requires glue to attach tiles to it, and that is a point of vulnerability. A birdbath or sculpture is a situation where mounting each tile individually is the best approach.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.