Mosaic Q&A

Mosaic FAQ

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General information about mosaic,    please click
Q. How to prepare home made glue the Orsoni style

Orsoni is the Smalti manufacture in Italy since 1888, and that is how they make the adhesive.

Ingredients: 10.6 OZ of flour \ a spoonful of honey | Half a spoonful of glycerine | A spoonful of gum-arabic

Put all the ingredients slowly into a large saucepan together with 1.75 litre of water, stirring until the mixture is even. Simmer while you stir it slowly and continuously for about 45 minutes without ever allowing it to boil. After turning off the gas, continue to stir it until it is completely cold in order to avoid hardening of the surface. In the end the mixture should have the same consistency as a sauce or mayonnaise. The glue can be laid on the sheet of paper/fabric with a brush, or you add the glue to tesserae with a stick, you can always make smaller quantity with the same proportion mentioned above. 

Q. Why red colours more expensive and how to make different colours?
Please check that article by David M Issitt

Q. What makes the grout to crack?

Too much water in mixing, the consistency has to be thick like peanut butter.

Q. Can I use these tiles around fireplace?
Yes, but make sure the binding materials are heat-resistant.

Q. How to use the basic nippers?
Place the blades perpendicularly on the tile; keep only 1/3 of the tile under the nipper, and gently with consistent pressure squeeze at the end of the handles to get a sharp cut.

Q. What would be the safety precautions to do mosaics?
Wear eye protection, gloves and grout in a well-ventilated area. Do not allow unsupervised children to play in work areas, where there is glass debris.
Clean your work area on regular basis and choose a surface that allows for easy clean up of broken tiles, and glass shards. Follow specific instructions from the manufacturer, when using different tools and materials. Contact a physician for more health information.

Q. Do I have to seal before grouting?
It is a must especially for stone, marble and pours tiles, otherwise grout will adhere permanently to tiles, and also to bring up the coloures.

Q. How to give a shiny look and enhance the colour of mosaic piece?
Use a soft cloth with few drops of oil and rub the surface.

Q. Does these tiles come in paper mount?
Only with special order and large quantity.

Q. How to remove dry grout from tiles?
Cover it with vinegar and water for 5 minutes, and then scrape it off.

Q. How to remove dry glue from tiles?
Rub it with acetone.

Q. What would be the step by step to do in-door mosaic?
1. Place tiles with the textured side down, smooth side up. While the adhesive is still wet, tiles can be easily moved into their desired position. Adhesive will begin to set in 5-7 minutes. Do not reposition tiles after it sets. Allow adhesive to cure for 5-6 hours before proceeding.
2. Once you have tiled the entire surface and the adhesive has dried, you may begin grouting. If working with ceramic tile, marble or stone, we recommend sealing the tiles before grouting, apply mosaic grout into the grooves between the tiles; be sure the grout is well worked into the spaces until the gout is levelled with the tile surface. When you have finished grouting, use a damp, wet sponge to wipe off excess grout. Allow it to dry.
 3. Once the grout has fully dried, take a damp cloth and polish the surface until it is free of grout residue.To protect your mosaic project, seal the entire surface with sealer.
Congratulations! Your mosaic project is complete.
Q. Can I drain grouts in the sink?
Do not drain any grout into pipes or toilets it will stay and ruin your plumbing.

Q.What is the Double Direct Method on mesh
It is just like doing the direct method but your tiles are adhered to fiberglass mesh instead of your substrate. Once the tiling is finished, you can install it anywhere, whether it is on a tabletop, kitchen backsplash, or an outside mural. Lay your design on a large flat area, cover it with clear plastic wrap, then lay a fiberglass mesh. Make sure that all of this is secured to the flat surface. If this moves during your mosaic, then your design will be shifted. Using Weldbond glue, start adhering the tiles to your design. You don't want to use to much glue so lightly dab the glue on the back of each piece. Follow your design that is under the mesh until you have completly coverd it. Beware of cutting the tiles over the mesh you will end up with shards stuck in the grooves. Allow the piece to set over night. Carefully flip the entire piece over and remove the plastic wrap. The glue should be wet at this point but your tiles should stay in place. Let the glue finish drying. if your mosaic is very large then you need to cut it into workable pieces.Mix your grout and lay a thin layerto the back of your tiles (buttering). Mix your thin set, spread a thin layer onto your surface and trowel through until it is half the thickness of the tiles. Position your mosaic then press dowen using wood block. Leave it to set overnight then grout as usual.

Q. The difference between the ORSONI Smalti and MEXICAN Pedromo Smalti
As the US Purveyor of Mexican smalti (, I would like to add my 2 cents about the differences between Mexican and Italian smalti. I use both! I love both! And I know all of you either will or do too!
The first and largest difference is cut. Both techniques pour a puddle of molten glass. In Italy it is called a pizza, in Mexico a tortilla. The Italian pizza is poured to a thickness of approx. 3/8", the tortilla 1/4. The Italian smalti poured thicker and cut into thinner pieces to expose the inside of the pizza. This inside (riven side) becomes the working surface of the material. By exposing the inside of the glass you will receive more vibrant, consistent, and reflective color. The pieces are more consistent in size on the visible working side but less consistent in thickness. Due to the varying thickness of Italian smalti in order to have a finished project with a smooth surface it needs to be set in reverse. (The reverse method is only required if you are looking for a smooth finished project.)
Mexican smalti is cut larger into irregular squares ranging from 1/2" to 3/4" on the visible working side with a fairly consistent 1/4" thickness. It more resembles a piece of tile. The working surface of the Mexican smalti is the top or bottom of the tortilla and has a fairly smooth surface without bubbles. It can be set direct with or without grout, because of its smooth surface, consistent thickness and lack of bubbles. Many artists including myself will set the Mexican smalti on edge if they are looking to add texture to their project.
Now on to color. In Italy, they have been making smalti for centuries. Their focus in regard to smalti is on the purity, brilliance, quality and consistency of the colors. To maintain these qualities the smalti pots are changed regularly and great care is taken in not contaminating the colors. The recipes are handed down and the making of the smalti is as much an art as it final use.
Mexican smalti is young by comparison. It has only come into existence in the 1950's. The production of Mexican smalti came through collaboration between a couple Italian Mosaic masters and a Mexican business man. There was a huge demand to fabricate murals and other mosaic decoration in Mexico during this time. Combining Italian recipes and new cutting techniques Mexican smalti was born. The direction of the "new" smalti material was to create a smooth surface with a hand cut feel, so that they could fabricate murals and other public installations with a smooth surface. They blended the Italian recipes but poured them thinner not to waste the material because they were using the surface not the riven side. In doing this they realized they discovered the rich mottled beauty of the surfaces of the glass. Less focus was on the recipes and pure color and more was put on the mottled painterly look of the tortilla. Often each side of each piece will be a different color and many different tones of the same color will come from each batch.
Because they are looking for the mottled color smalti "pots" are not changed regularly. When one color is finished, a new color is mixed and the two begin to blend creating the mottled color. As an artist and retailer of Mexican smalti this is a blessing and a curse. It makes for such beautiful color variations in a single batch, but makes it more difficult to reproduce colors from one batch to the next. My advice when ordering smalti is always order more than enough to finish your project colors do vary particularly in the case of the Mexican smalti.
When deciding which to use for you particular project, it can be as simple as this. If you are doing an installation or require a smooth surface it is easier to do this with Mexican smalti. If you are looking for texture and reflectivness, Italian smalti can't be beat. Or you can do as I do use both!
As for price, in the US they are fairly equal.
I hope I have added some insight to your choices in the future.
Answered by: Kim Wozniak (USA)

“Smalti” is the Roman word for “melt”. Smalti is hand-made in Venice and until recently there were only three families still making. The recipes and techniques have been kept secret and handed down through the generations. Glass is melted in a cauldron, then poured out onto a metal sheet where it is pressed down like a pizza which is then sawn up into little briquettes about 2 x 1cm (3/4 x ½ in). It is supposed to be used with the sides uppermost, thus emphasizing its rippled surface. Tiny air bubbles in smalti are part of its intrinsic quality.
Smalti can be bought as a 20kg irregular mix box, known as “roti”. This will contain tesserae that have a curved edge – these are the edges of the “pizza”. Purists would argue that these shouldn’t be used, but I find them invaluable for details.
Hand-made smalti is very expensive, but it makes a lovely addition to any mosaic and can be incorporated in small quantities.
Because of its uneven surface you do not need to grout smalti when working direct. It “self grouts” – as you push the smalti into the tile adhesive, it is forced up between the gaps in the smalti.
With Mexican smalti both sides can have a different coloration and one side usually has a patina on it which is to do with the cooling process. The molten glass is poured onto a metal plate, which is a conductor of heat so that side stays warm, whilst the top of the “tortilla” is exposed t the air which isn’t a conductor of heat. (It’s rather amusing that the Mexican’s call the smalti ‘cowpat’ a tortilla whilst the Italians call it pizza!) The side that is exposed to the air cools at a different rate to the underside that is touching metal and that is why sometimes you get a patina; always with the Mexican actually which has the most beautiful patina on it. It’s irregularity means that it is more fiddly, but I like it a lot. The Italian is more regular generally 1 x 2 cm briquettes so it is easier to use in a way. Here in England. Mexican is more expensive because we have to ship it from Mexico, which is a long way away and pay import duty on it whereas Italy is nearer and because we are in the RU (European Union) we don’t have to pay import duty on it. So here the Italian smalti is cheaper but in America it is the other way around – the Italian is more expensive than the Mexican.
I like both, it just depends what I am doing as to which one I choose.
Answered by
Martin Cheek (England)

Q. History about mosaic
Emperor Diocletian in the beginning of the third century issued a decree establishing rates of pay for the various grades of mosaic artists. And in 330 A.D. Emperor Constantine transferred the imperial seat from Rom to Byzantium and granted mosaic artists tax exemption to encourage them. The technique of gilding tesserae in the Byzantine era, by applying a fine gold leaf to a sheet of plain or tinted glass about 8 mm. thick, covering it with a layer of powdered glass then firing, the resulting materials was ideal for producing colour effects because the unevenness of the powdered glass and consequently of the overall thickness created variations in tone and enabled gold to be used on very large areas. The popularity of mosaics began to decline in the thirteenth and fourteenth century being superseded  by painting on canvas and frescoes.

Q. What is Revenna technique?
This method is also called the Double Reverse method (the mosaic is set on lime putty, gauze is glued over the top with home made glue or weldbond and when it is dry the mosaic is lifted off the line bed and set onto a base with cement. When the cement sets the gauze is removed. This is used to make a reproduction copy of ancient mosaics or where you need a 'flat' surface but use irregular thickness tesserae.
Q. What is the Lime and how do use it in Revenna style?
Limestone past is Lime soaked with water to form a putty. With l
ime you work face up meaning you see your finished work, this is important for portrait work and you do not need to worry about cutting your tesserae to the same depth as in the Vincian technique.The tesserae will hold in the lime, you just press them in and they stay there. The great thing about the lime putty is you can remove tesserae if you want to change them. The replacement will still be held in place. When the mosaic is finished, glue the gauze on with rabbit skin glue, a water soluble type or diluted weldbond glue. You learn how much lime you need to remove by experience, just enough for the cement to attach to each tesserae.