Mosaic Sinks

Someone recently asked me about how they could make a Moroccan-styled Glass Mosaic Sink, and that got me thinking about different options for making mosaic sinks in general.

How to Make a Custom Basin from Thinset and Hardware Cloth?

To make a custom shape such as the simple elegant shape used in the Moroccan sinks I have seen, I would probably use a large ceramic serving bowl reinforced and extended with thinset mortar and hardware cloth (wire mesh). Actually I would probably use the bowl only as a mold for the curved bottom and build the sink up in layers of thinset and fiberglass mesh, Once I had a few layers, I would let that harden. Then I would cement in some hardware cloth and use a 1/4″ rebar hoop to stiffen the outer rim and support the bowl. Make sure the hardware cloth extends past the rebar hoop. Fold this back down over the hoop and lay if flat on the outside. Cover this in 2 coats of thinset,

Of coarse, you need to have a metal drain cemented in place from the very beginning. I would use the upside-down bowl as a mold to get the curvature I wanted, and I would leave the fiberglass mesh bare in the very top where the metal drain will be placed. I would stick the metal drain  in a hole in the middle of the hardware cloth. I would fold this hardware cloth down on the outside of this shell and made sure the metal drain matches up with the bare fiberglass mesh at the top of the inverted sink shell.

That is similar to how I made shapes for sculptures. Sometimes I would use an object as a “mold” to define the shape by draping it in mesh covered with thinset, and other times I would weld up a rebar skeleton and cover it with hardware cloth first and then cover this skeleton with thinset.

How To Use A Conventional Porcelain and Iron Sink As A Mosaic Base?

I’ve always thought about making a more contemporary mosaic sink, a wall mounted unit or maybe even a pedestal.

For either one, you could use a conventional sink (glazed porcelain or cast iron enameled with glazed porcelain). I’m always seeing interesting ones in construction dumpsters and beside the road on pickup day. It’s not like you have to wait too long to find one if you keep you eyes open on streets where they were restoring old houses.

The question is how to scuff up the porcelain so that the thinset sticks to it extra tight. Maybe the artist will get lucky, and the one in the construction dumpster will be 80-years old and used to rinse mops and scratched and stained. If not, I’d probably use a dual-grit rubbing stone an a leather work glove to scuff it up. I do stuff like that wet of course to keep from making a bunch of air-born dust. Remember, a mist bottle is often more effective than a dust mask, and a lot more comfortable when it’s hot.

You could definitely make an interesting mosaic sink from some of the glass tile I sell.

However, none of my glass is certified to be safe as a food preparation surface like a dish or a cutting board. This might not be relevant when talking about a counter top, but a sink is different.

Some people use their sink as a bowl for soaking vegetables and frozen meat. I wouldn’t do that in a sink made from stained glass because I would want to be sure that none of the softer varieties of stained glass were shedding metal oxide pigments. I wouldn’t rule that out in a sink which is subjected to organic acids and spoiled food on a regular basis and chronically damp. You could avoid the problem by using a bowl for soaking food and keeping the sink clean of food residues.

Recycled Glass Tiles

The Elementile brand of Recycled Glass Tiles would be an interesting choice for a mosaic sink, and probably the most durable glass material we have for an application like that. Elementile is small and available in a range of colors too, so you could have a fairly detailed design without having to cut it or supplement other types of glass to make up for missing colors. I’m sure this is what I would use. I would use the standard finish Elementile and avoid the iridescent version of the product.

Stained Glass

I have seen smaller pieces of stained glass used in some amazingly detailed figures in mixed medial counter tops that ranging from repeating borders in conventional ceramic tiling to found-object mosaics that included artifacts like beach bonfire glass and boyhood collections of arrowheads.

Use Small Pieces for Mosaic Counter Tops

I think I would avoid large pieces of stained glass for a sink or a counter top because some of it is very brittle, and all of it is relatively thin: nominally 1/8 inch. Most all of the glass mosaic tile is nominally 1/8″ thick, but none are larger than 1″ x 1″. There is a relationship. When the thickness is relatively thin, the piece size can only be so large before it is too easily cracked by a falling object.

Smaller tiles are less likely to crack than large ones. Here’s why: With smaller tiles, there are more lines of grout between the tiles. The grout between tile is concrete and actually helps strengthen the face of a glass mosaics to blows.

In general, I would probably avoid stained glass for sinks and only use it selectively in counter tops and those backsplashes that are less likely to see impacts from dinnerware being slung and slid around.

10 thoughts on “Mosaic Sinks

  1. Mark Swan

    Thank-you for sharing all your expertise on mosaics in general. I think that your website is great. I would like to make a twin bowl sink for the kitchen. My plan is to take a slab of wood and carve out the two shapes for the two sinks and then mosaic tile the carved out base. Thin set seems a very good option for setting the mosaic pieces in place, perhaps a type that allows some flexibility for seasonal movements in the wood. Would you think that such a design could be effectively grouted and what would you suggest for grouting? Best Regards, Mark

    Reply
    1. Joe Moorman Post author

      Many of the articles in the blog have explanations of why wood does not work as a backer for wet or outdoor mosaics. Our article on mosaic tables explains what some of the alternatives are. I would use hardware cloth and a welded rod frame and cover that with thinset.
      Thanks,

      Reply
      1. Mark Swan

        Thank-you, Joe, very much for your reply. I agree with you. Wood is subject to movement, thus the application of mosaic via a cementatious or adhesive layer may not be a good idea since the sink needs to be waterproof. However…….I am a carpenter so rightly or wrongly have used wood as a backing layer, my more specific reasoning being as follows:

        I have used recycled “glulam” beams and formed them into the sink base. This wood would have been kiln dried to a very low moisture content and are also quite a few years old so I would say that the wood is pretty stable. I would not advocate using green wood or wood which had not undergone a complete drying process. Fully dried or recycled wood is therefore ok as a backer, in my opinion. In this way in such a sink top or any countertop the wood could also be expressed aesthetically to compliment the mosaic.

        Assuming the mosaic is then fitted to the timber using either as you suggest something like thinset or an adhesive suitable for porcelain/ceramic/glass on wood, it is then necessary to completely seal the mosaic from any water ingress.. This as you have pointed out is dependent on virtually no movement in the backing or the adhesive and mosaic. At least any movement that does occur from use of the sink or movement due to shrinkage needs to be taken up by the ability of the seal coat to take up the movement.

        So far I have cut the sink top and am in the process of forming the two bowls out of the recycled wood. The mosaic is to be formed from broken pieces of porcelain, ceramics and glass that have been found on our local beach. I am researching a flexible clear seal for the sealing coat, as yet to choose this.

        I will keep you posted of progress and arrange to have photos posted. Lets hope it works!

        Best Regards ,

        Mark

        Reply
      2. Mark Swan

        Hello Joe, I’m moving forward with the wooden base sink design. I have contacted an adhesives company who have been very helpful, their technical suggestions being: 1) waterproof the bowl of the sink with their brand of waterproofing which is also used for swimming pools. 2) adhere each piece of mosaic with a flexible mastic, thus giving the necessary flexibility between the wooden base and the mosaic. 3) grout with their waterproof grout. I will post photos of the work in due course. I have another order or a client in Switzerland to make her a wooden sink with a mosaic insert. I will make the base in the workshop and would also like to make the mosaic for the bowls as well in the workshop so that I can transport the finished mosaic and then fit into the bowl on site. Is there a way to do this? I am wondering if it is possible to lay a mosaic shaped to the bowl profile on a matting and then taking this to site and fitting the mosaic on the matting to the bowl on site.

        Reply
        1. Joe Moorman Post author

          I would make the bowl from hardware cloth and thinset mortar. I would never ever consider using wood no matter what it was sealed with. I am an engineer with a lot of hands on experience, and I can’t begin to put into words how vulnerable that wood would be. Of course you can use the method you propose, but it only takes one pinpoint Achilles heal to ruin the whole thing. Flexible mastic would be problematic.

          I hope this helps more than it frustrates.

          Reply
          1. Mark Swan

            A good honest very helpful response, Joe, and one I agree with. Thank-you because I think that I was perhaps gong on the wrong track with my suggestion. So now I have to think of the way forward. The sink is made out of wood. It is stood here in front of me in the kitchen and actually looks quite nice. It has driftwood legs and the underside of the wooden bowl can be seen so it all looks organic. So now I have the wooden bowl which I have to mosaic because my wife has painstakingly collected all the mosaic pieces from the beach and is really expecting this mosaic sink! So I think I have two possibilities. One as you say is to use “hardware cloth” and thinset. So I could form the bowl shape in situ on top of the wooden base (which is basically a worktop with the two wooden bowls set in) by laying the hardware cloth over the two wooden bowls and then making a mould of the bowl on top of the wooden bowl using thinset. This then remains in place. I would lose a little height and width in the bowl because the hardware cloth and thinset would also have a thickness. I would hope that the hardware cloth and thinset would take up any differential movement in the wooden base. I can then proceed to use further thinset to bed the mosaic and then grout. The alternative would be to fibreglass the existing wooden bowl and then lay the mosaic. I think though that your suggestion is the better way forward? One other point is that I have applied a 5 to 1 water and pva mix over the existing wood which I had been advised to remove by the manufacturer so that there waterproof could be applied (pva re wets itself apparaently). Using the hardware cloth/ thinset method I don’t thin that I would need to remove the pva. For the other project for the client who likes the idea of the organic feel of the wood, I would make the wooden top and leave two holes in that so as to inlay on site two bowls made using the hardware cloth and thinset method that you have wisely suggested, I could as you say in your articles stiiffen up the rim with some thicker steel bar wich could be cut into a rebate in the top. Does this now make better sense? Is there a way I can post a photo of the wooden base that I have made so that you and others who read your forum can see it.

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