I had an old set of Jelly moulds that were going in the bin. They have been well used but some of the lids are lost over the years. I love the shape, so I decided to cast them in concrete. This small size is perfect for candle holders and their wide flat base makes them safe to use.
- SNOWCRETE (white cement)
- kiln dried sand
- jelly moulds (or a different container that has a good shape)
- small youghurt pots, large enough to fit a candle of your choice.
- Little candles in metal pots
- Heavy duty Tape
- Safety googles
- Plastic gloves
- Plastic sheet to protect the floor
- Plastic bin bag
- Optional: release agent or wax
- Optional: Polyfilla
I was really lucky. I had some little yoghurt pot containers in my recycling bin. They were small enough to fit perfectly into the little whole at the top of the plastic mould.
Insert the yoghurt container upside down into the base of your jelly pot, and tape it in place. Use plenty of heavy duty tape and make sure the edge is water tight. Remember that no tape should be on the inside of your mould, as that would create ugly marks. The depth of the inserted yoghurt pot will determine how deep your candle will sit in your final holder. I made a set of four holders as I had several jelly pots, so I had to be careful to get the exact same depth on all four. Preparing the mould well is vital when casting a product. It is hard to make changes once the concrete is poured.
Prepare your area. You want to cover the ground with plastic. Place the prepared moulds upside down inside of an opened bin bag. Concrete dries harder if it dries slowly. Wrapping the concrete air tight in a bin bag as it cures, will add a few days to the process and therefor increase the quality and strength of your final piece.
Be safe. It is important to use googles, a mask and plastic gloves. Breathing in the concrete is dangerous and it can burn your skin and damage your eyes. I always read the manufacturers safety data sheet for further instructions and I advise you to do the same. Be careful as you handle it in both powder and wet form.
Mix your concrete. You need to use one part Snowcrete to two parts sand. Start with stirring the two together well before adding the water. Add small quantities of water at a time. It is easy to make concrete to thin. Aim for the consistency of a solid porridge! You don’t need a large mix. It is heavy work mixing concrete in great quantities, but very easy in small batches.
Plop in the mix. Vibrate the mould in your hand as you are filling it. Keep vibrating and tapping and you will see air bubbles rising to the surface. The more bubbles you get rid of at this stage, the smoother your surface will be. I have attached a montage of two pictures below. It is two of the holders after I removed them from their moulds. You can see that one is smoother and that the other has a large amount of markings from trapped bubbles.
Seal the bin bag around your casted objects. Leave them alone for three or four days.
Removing an object from a mould is the best part of the process. It is so exciting to finally see the result! But it can be a little tricky. A water bath can help releasing the object. Sometimes it is enough to insert a knife or similar around the edge, bending slightly. In this case I started with removing the yoghurt pot, which allowed access to push the concrete out from that end.
Concrete dries out your skin. It can also still be curing even if it is hard to touch. Curing concrete can corrode your skin and cause serious burns. Therefor you should always wear your plastic gloves as you remove items from moulds, sand them, scrape them or handle them.
There might be air bubbles or other blemishes. Sometimes you end up with a damaged edge from bending the object out of the mould. Some of these marks can add beauty, and some are unwanted. You can use polyfilla to fill air bubbles, cracks or scratches.