I am delighted to present a guest post (my first) by award winning Canadian mosaicist Julie Sperling about using thinset for mosaics. Julie’s work stands apart in being both fiercely beautiful and intelligently polemical. In her hands mosaics move out of the decorative realm and into a hybrid world where art meets politics meets activism. Using a wide range of tesserae and found objects from the traditional (smalti and limestone) to the unusual (grafiiti paint layers) and the bizarre (flue damper), Julie explores the subject of climate change and our human response to it through mosaics which make your heart sing and your thoughts linger.
How does she do it? you ask. I have often wondered. No one (probably least of all Julie) could precisely explain the process by which she interweaves her materials with the subject matter to create works of art but Julie’s work is impressive on many levels, including its sheer technical virtuosity. In many of her mosaics the substrate is part of the piece rather than just a surface to be mosaicked. It’s a pause, a space, a frame, it allows her to open the work up to infinite suggestions, to make emphases, to change direction and to add permutations and explorations both on and beyond the ‘canvas’. See how she does it here in Heat (Each Decade Hotter Than The Last) where the central ‘graph’ is separated by a perfectly balanced border of thinset:
Thinset (or mortar) isn’t an attractive word or in most people’s books the most appealing aspect of mosaics, but in this blog post about using thinset for mosaics, Julie shows us how this most mundane of substances can be used to create stunning effects. Many thanks Julie!
Julie’s Tutorial: Using Thinset for Mosaics
First, my go-to implements for the task: an array of paintbrushes, spatulas, and palette knives, as well as water and a rag. And don’t think I only use the brush/blade end! Anything is fair game, including fingers.
Now, if you want to save yourself work, make sure your initial bed of thinset is as smooth as you can make it. Just like taking a good photograph to start will save you time and frustration in post-production, touching up a smoothish surface is much easier than trying to fix an area riddled with bumps and ridges and lumps later on. A pass or two with a clean palette knife (wiped with a damp cloth) will make your life much easier. Admittedly, though, I usually skip this part or, at best, make a half-hearted attempt to get a nice smooth bed. Why? Because I’m not really great at using a palette knife and because fixing it later doesn’t particularly bug me.
Smooth thinset in between lines and tesserae
When I weave my lines, I like the thinset to be smooth, especially where there’s more open space. I have no reason for this other than personal preference. Once I set my tesserae into the thinset, I leave them for a bit before attempting to go in with my various implements to smooth it out. I’ve found it’s far easier to work with the thinset once it has set up a bit—it’s less sticky and far more compliant. I just pat it / brush it as best I can, mostly with a dry brush or other tool (or, more frequently, the blunt end of a tool).
Sometimes the thinset dries shiny and smooth. I don’t particularly care for this look, so I will take a slightly thinner mix of thinset at the very end (when I’m cleaning up the background) and just dab it into the small spaces, being very careful not to get any on the tesserae.
Smooth thinset as the background
I save this step for the very end. I spread my thinset on the background, usually in stages (I find doing one side at a time works well for me). I try not to put it on too thick (because then it just squishes around when I try to smooth it with my brush) or too thin (because then the roughness of the substrate comes through).
Then I take a foam brush, wet it with water, and squeeze the excess out with my cloth so the brush is just damp—this is very important, because if your brush is too wet you risk getting white splotches on your thinset once it dries.
I lightly brush the thinset with my damp brush to smooth it out, taking care to keep my brush strokes going in the same direction. I find that shorter, quicker strokes work better for me. When too much thinset accumulates on my brush, I rinse it, wring it out in my cloth, and keep going.
Sometimes I have to switch to a smaller brush to work closer to the tesserae, but normally I can make it work by angling my foam brush this way and that to follow the curves of the outer tesserae.
And that’s it! It really all boils down to working as neatly as you can from the start to save yourself the headaches later on, making sure your brush isn’t too wet, and being patient.
Thanks for posting this lesson! Great to see the process.
Thanks Julie and Helen for sharing! Very usefully!
Thank you! I’ve been anxious about working with thinset and I think this has given me a bit more confidence I just need to jump in a try it
Excellent tutorial! Thanks for generously sharing your method Julie! And Helen for all your other tutorials which are very clear and helpful to me as I am a beginner in mosaics.
Great explanations Julie. The detail photos are particularly illuminating. I find that a flat headed brush is key.
Thank you Julie very informative and enjoyable read and technical discussion.
Geoffreu
I am so glad to have found this website! Wonderful, clearly-explained (in words and pictures) and enjoyable to read. Thanks for your generosity in sharing this.
Hi, great works
What kind of addisive did you use?
Thanks
I use BAL Turbo Set Tile Adhesive from Topps Tiles which comes in grey and white and then you add pigment (available from art shops)but of course it will depend which country you live in! I’ve heard that others recommend BAL Blue Star Fibre Enhanced Tile Adhesive which comes in tubs and is ready mixed. I hope that helps.
Vi seus trabalhos no Pinterest! Achei maravilhosos, vc eh uma artista nata!!! Parabens!!! Amei sua arte musiva!!!!
So then you don’t need to grout?
Yes, that’s right Maggie. I am working on a blog post on the basics of thin set to further explain this great method – coming out soon!
How do you use the adhesive with the thinset ? Do you adhere the tessarie first ? Lovely work thanks for sharing
Hello Andrea. The key thing you need to know is that thin set IS adhesive. I don’t know where you are based but in the UK we call it tile adhesive (and I use BAL’s Turbo Set Flexible Tile Adhesive for Walls and Floors available from Topps Tiles) and in America it is called thin set. I am in the middle of making a new tutorial about the basics of using thin set and will fill you in with all the details but basically you follow the manufacturer’s directions on the packet and make a paste which you apply to your substrate and then push the tesserae one by one into the adhesive. I hope that helps! Good luck with your mosaicking.
So is using grout just an artistic choice? If the tesserae stick well with just thin set, what is the function of grout?
You use grout or not depending on what method you are using. If you are using the thin set method you don’t need to grout because you are pressing the tesserae into the thin set so they are self grouted and held in place by the thin set. I will publish a new blog post at the end of this week about the basics of thin set so you can see what I mean. I hope you find it helpful, Helen.
May I ask what the surface is you are working on in these pictures. Many thanks beautiful work. Stunning
Julie uses Wediboard which is easily available in the US. I found it harder to get hold of here in the UK and very expensive so I use Jackoboard which is essentially the same thing. I have just written a new blog post about the basics of the thin set method which talks about the substrates too: http://helenmilesmosaics.org/blog/tile-adhesive-method/. I hope that helps. Helen.
Thanks for this very informative tutorial. It helps demystify things a little. What beautiful work you do Julie and thanks Helen for hosting this. Continued success.
Many thanks for this, Cem! I’m glad you found the tutorial helpful – Julie’s work is truly amazing.
Wow! Never considered not using grout. You are brilliant!! Thanks so much.
Thank you so much! I have wanted to experiment with thinnest as a larger part of a piece. Great pics and explanation!
So glad that it was of use! 🙂 Helen
I can’t wait to try the method..the explanation is great to understand and follow it. I’m used to make a mess everyday in my art room so I don’t care, ha,ha
Thanks so much..
That’s nice to hear, Aileen. Go for it! 🙂
What do you use to dye your thin set? Your dark grey or black looks so nice and rich. So often colored concrete dries a faded color.
Hi Cynthia, thanks for your enquiry. It depends on where you are based. I am in the UK and use black Mortar Tone produced by Ever Build and available at Screwfix or other outlets: https://www.sealantsandtoolsdirect.co.uk/everbuild_208_powder_mortar_tone_colouring_1kg_black_ but I think in the US you can buy all sorts of colour additives for thinset from mosaic suppliers. I hope that helps!
This is interesting, thank you for sharing. I’m guessing the thinset is colored? And the artist works in small batches to event out the thinset and lays out the thessarae individually in place to form her lines and uses brushes to smooth out background. I’m guessing that there is no grouting of the pieces involved in the end?
You’re welcome! Yes, the thinset is coloured and yes Julie works in small batches laying her tesserae into the fresh adhesive and doesn’t grout at the end because the thinset acts as a grout by coming up between the individual tesserae and holding them in place.
Very interesting. I have been gathering many different colours of stone here in BC and have a diamond wet saw to cut the stone into slabs to speed up the process of making the tesserae on my hammer and hardie. I have a few projects in mind that will work well I hope with the colours of rock that I have collected. After reading your post I am anxious to finally get started learning how to do mosaics. Such a beautiful ancient and durable art form that can add real beauty to a home.
جميل جدا ورائع انا احب الفسيفساء واعمل به
Shukran gazeelan ya Fatima!
I’m so thankful to find this method, because I’m wanting to use thin set as a background for my mosaics and now I can! Can this method be used for outside mosaics? My mosaics will be hung outside in my garden.
Yes, it can 100 per cent be used outside. Just make sure that the tile adhesive/thinset mortar that you buy is suitable for outdoors.
Great article, thanks for this.
You’re very welcome Clem!