You don't see coloured grout very often and I could never understand why. Colour makes everything better and I've seen too much white grout, so I decided to do make this project using purple grout.
Boyfriend wanted Spanish mosaic side table, I wanted Escher table and we landed on Escher inspired tessellation tiles table. I made the tiles myself using a 3D printed Escher lizard, home made gelatine moulds and plaster of paris.
I had an epiphany whilst working on the moulds. I had no idea gelatine could work so great and copy every tiny detail. Not to mention that it saved me a lot of money because I didn't have to buy expensive silicone.

Supplies

Enough for 3 moulds:
-108g (9packets) unflavoured gelatine
-600ml water
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-plaster of paris
-strong, multipurpose glue

-slow drying glue (like acrylic adhesive)

-Dremel, craft knife, sanding paper, sanding block

-petroleum jelly and WD-40 (or other spray-on lubricant)

-grout and heavily pigmented paint (acrylic or wall paint)

-non-yellowing varnish

Step 1: GELATINE MOULD

3D print one lizard, print it with a brim to ensure all legs are flat. Don't worry about smoothing it, it doesn't have to be perfect, just trim the brim.

Prepare gelatine. Pour 300ml of boiling water in to a jug, sprinkle 108g of gelatine and stir until dissolved. Add the remaining 300ml of cold water to speed up the cooling process.

Assembly a mould box. The most important thing is to use a very rigid base to make sure there is no warping or lifting. I used old, glass chopping board. Use whatever you have on hand to make walls- cardboard, acrylic, PVC coated foam boards, melamine boards, plastic containers. I used cardboard pieces, glued them with a glue gun and covered the inside of the walls with scotch tape to make sure gelatine doesn't disintegrate the box.

Use strong glue (not superglue) to attach the lizard to the base and prevent the legs from lifting up. Once everything is safe and secure, it's time to apply lubricant. Use a small brush to apply petroleum jelly to the lizard, get in all the nooks, lubricate them well, but don't leave too much jelly inside.

Pour gelatine mixture in, try to keep the mould around 10mm thick, any thicker and it won't be flexible enough to peel off.

Pop the mould in the fridge, gelatine will be set in 30min. Don't destroy the box, just cut away as much of the gelatine mould as you can, peel it off gently, set it aside and create more moulds.

BIG LIZARD.stl
Download View in 3D

Step 2: PLASTER OF PARIS

Place the moulds onto a flat, sturdy board. Spray the moulds with DW-40, mix a small batch of PoP and pour that in. Spread the plaster evenly with a spatula, bang the board against the table to level the mixture and allow the air bubbles to rise to the surface.

How to mix plaster of paris.
Use a kitchen scale to weigh plaster and cold water. You need one part of water to two parts of plaster (1:2). Sprinkle plaster into water and stir until there are no more lumps. Water has to be as cold as possible to keep it from setting too fast.

I filled all 4 moulds at once and used 90g of water and 180g of plaster each time.

Step 3: TILES UNMOULDING

Plaster will be ready to pop out of the mould 1-2 hours later. Plaster sets fully after 24-48 hours, but I had no intention of leaving it in the mould for that long because gelatine hardens after 1 day and that mould would not be usable anymore. Be very careful when removing it as it will be fragile and prone to cracking. Flip the whole mould upside down and peel it off the lizard rather than pop the lizard out.

Make as many tiles as needed. Don't forget to apply WD-40 each time.

*I used a 3D software to roughly determine how many tiles I will need for my table.

**If your gelatine mould hardens around the edges (usually happens after 24-36 hours) or if you accidentally destroy the mould, you can always melt it and cast a new mould.

Step 4: CLEANING

Let the tiles dry for 24-48 hours. Use a craft knife to cut away the excess brim around the lizard. Don't throw any broken tiles, they will be used later.

Step 5: SANDING

I had this old coffee table and it was in a desperate need of some TLC. I cleaned and sanded the top and then tried to determine how to place the tiles on. Once I decided how to place them, I glued the tiles with a strong glue suitable for both plaster and wood. Slow drying glue is the best in this case as it will allow you to move and adjust the tiles. Use broken tiles to fill the edges.

Once the glue dries it's time to trim the tiles with Dremel. Use a sanding block to smooth the surface of the tiles. Make sure the whole surface is as flush as possible. Hoover everything to keep it dust free.

Step 6: GROUT

I mixed a small pot of ready mixed grout with some heavily pigmented, purple wall paint. I used a spatula to spread it around and push it into the cuts as much as possible. I cleaned it roughly and left it to dry.

*Originally I wanted the yellow tiles with purple grout. I painted the tiles, but grout got them so dirty that I was unable to clean it and I was forced to sand away that paint layer. Turned out to be a good thing as I hated that yellow colour in the end.

Step 7: MORE SANDING

Once the grout dried I was able to sand the yellow paint and leftover grout. I sanded the top with 120-grit until it was smooth and level. Grout colour won't be very visible at this point. It will have to be varnished before the real, vibrant colour shows up.

Dust and hoover the whole top, apply 2-3 coats of varnish and leave it to dry.