Mosaic glue choice
There are many different options that you can choose for a tile glue – all of them have advantages & drawbacks.
I almost always choose a polymer modified cement glue (often referred to as thinset) as it performs very well in nearly all situations. It’s waterproof, has strong adhesion, is shockproof, flexible and is cheaper than most other methods. Best of all, it works for virtually every situation.
The product I use (and supply with our kits) has the polymers in the powder – for larger projects on flexible substrates, an additive is available to further improve it’s qualities if needed.
You’ll need to talk with your local tiling specialist to get the right product (you won’t find it in a hardware store) – ask them what they’d advise for installation in a submerged pool situation and you’ll be on the right track.
Adhesives that can also be used (but not recommended by myself) are Weldbond or PVA glue, construction adhesive (liquid nails, maxibond), exterior silicone or even a cement tile glue without the polymers (only on rigid backing materials).
Glue preparation
It’s really best to make your mosaic glue in small batches to minimise waste though this method will give you hours longer “pot life”.
 | Put your glue in a separate container, and whilst slowly stirring with a spoon or spatula, add your water slowly. Make sure you scrape all the dry powder off the bottom of the container. |
 | It’s very important to achieve a consistency of about toothpaste – too dry and your glue won’t stick to your tiles – if too thin the glue will lose bond strength.A good consistency test is to stand a spoon in the glue as shown. If it doesn’t move, and the glue is still sticky to touch your mix is about right. Add water or glue powder in small amounts until you’re happy with your consistency. |
 | Fold back the top of a plastic bag and stand it in a container to help you spoon the mixed glue in. Try not to make too much contact with the sides of the bag. Splitting the glue mixture into two or more bags is a good idea. If you’re using your own plastic bags, ensure they’re the strongest you can get. |
 | Remove as much air from the bag as you can, twist the top of the bag a few times & tie with a twist tie. Store the bags in your fridge when you’re not using them and they could last up to 24 hours before setting. To further prolong their life, mix the bags a few times a day by squishing them thoroughly. |
 | When you’re ready to start using the glue, simply snip a corner off with scissors or a stanley knife. You can then squeeze the bag & it will make a bead of glue from the hole. Experiment with a smaller hole to start with – you can increase the size easily enough, but not reduce it. |
