(Q)(Ref:AD32) 22/04/01 What product is produces a good bond for exterior mosaic projects. I tried a clear silicone caulk and it failed miserably! Was adhering tiles to concrete and they peeled off, would like the brand of something I can readily find and use on a variety of surfaces.

(A)For outdoor work the ideal adhesive to use is cement based. Either a cement based tile adhesive or a sand and cement mix. Of course the tile adhesive MUST be both water-proof and frost-proof.

Cement base adhesives can be bought in bags from 2kg up to 22kg. They must be mixed to a firm consistency and applied to a dry surface. Your mosaic tiles are then pressed into the mortar to give a good contact.

Work with a small amount at a time as you will normally have about 20 minutes working times with each batch. To help improve the flexibility and adhesive properties of the mortar add a plasticizer or polymer additive to the mix one part additive to two parts water. This is the preferred mix if you are making a mosaic for a predominantly wet location. Add this to the cement until the required consistency is reach.

If using sand and cement mix use the ratio 3 or 4 parts fine sand to 1 part Portland cement. Mix thoroughly and add water. Mix to the required consistency. It is advisable to wear gloves whenever you are dealing with cement based products.

To improve the adhesive and strength properties of the mortar, the setting time should ideally be long and slow. So if you can cover each days work with a polythene sheet to protect the work and help the setting.

(Q)(Ref:AD18) 10/09/00 I'd like to make a mosaic out of pebbles from the beach - will the salt in them react with adhesives? (I usually just use water-resistant PVA or sometimes epoxyresin). Is there anything I should soak them in first? Is there an adhesive that won't react?

(A) Hi,- about your sea pebbles query in Mosaic Matters, I've used them quite often . Wash them thoroughly in fresh water to remove the salt, and then glue them as usual. I've set mine in with Ardurit (exterior) for outside work, and always use an exterior quality Unibond (pva) for interior pieces. It is more expensive but I think the extra strength is worth it. Elaine M Goodwin suggested this on one of her workshops, and certainly I don't have problems with bits falling off Jan O'Highway

(Q)(Ref:AD9) 09/04/00 I am thinking of covering a wooden picture frame with bits and pieces of broken pottery as a way of recycling memories. I wonder if someone could tell me what type of adhesive and grout to use for the project since it is the first time I am doing it. I would l like to approach this in the easiest and least expensive way since after my initial experimentation I will be doing it with a group of friends for fun.

(A)I've done them with a water base adhesive from the hardware store called "Wellbond". Be sure to rough up your wooden base with a sharp instrument to give extra grip.I've done several and so far so good. They are decorative and , of course, shouldn't be subject to abuse therefore it all holds together very well. To even the surface or to add jewellrey i sometimes use the mastic as well but the white glue works great.

(Q)(Ref:AD3)1/8/99 I have purchased a bird bath and would like to mosaic the inside only like a swimming pool, what adhesive and grout would be best suited for a mosiac which will be submerged in water all of the time.

(A)I have been using clear waterproof silicon to set my pool mosaics for five years and have never had a customer call back with any problems. www.mosaiccreations.com

(Q)(Ref:AD2)18/7/99 I am just getting started on my first mosaic. I'm going to combine stained glass and vitreous tile in the same design, which will be applied in the direct method to the arch doorway in between two rooms in my house. Any suggestions on the type of adhesive I can use to glue the stained glass to my wall? It needs to dry clear.

(A) I have used stained glass in combination with tile; I had great success with the stained glass reflecting light by using a white adhesive behind it, versus a clear adhesive. The white intensifies the color of the glass without interfering with it. Go to my website www.alltherightangles.com, select Applications, and then click the #3 thumbnail DETAIL backsplash. The smaller rectangles of miscellaneous glass and tile that are between the larger square tiles show how the stained glass looks.






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