Obviously you can put any message on it. Anything from "LOVE" spanning to Ramones' classic lyrics "HEY HO, LETS GO" will work. Depending on the size of letters (or the size of your concrete sculpture).
Disclaimer; Concrete may “explode” or crack at high temperatures. The likelihood of this occurring will depend on
temperature, tension and moisture content. This is something engineers need to take into account when, for example, construction a subway station that will withstand a fire long enough to allow people to evacuate.
In the specific case of my concrete candle holder, I would say that the likelihood of an explosion is low. As it is an open, well ventilated construction with a relative large mass of concrete to absorb the heat, it is unlikely that the
concrete will ever reach critical temperatures of around +350 degrees celcius (660 Farenheit).
Also, the candle holder is not under any external pressure/weight (although the heat may create internal pressure). However, depending on how (badly) you build your candle holder - it may break or crack. This could cause a fire.
A tea candle is also a potential fire hazard as the candle may melt creating an overheated fluid which may create a much larger flame than intended.
So, as a disclaimer - never leave this or other candles/candle holders unattended!
Step 1: Set the Text in Your Mold
Step 2: Pour Concrete Into Your Mold
Rub some oil into the plastic container to make sure the concrete will release when it is dried (burned). Pour concrete into mold. Tap it gently to avoid air bubbles.
Let it dry for a couple of days while watering the concrete daily to avoid cracks.
Break the mold and behold your creation!