Having succeeded in creating items with thinner walls, I started looking for ways to end up with smooth edges, without sanding. Before I move on, I need to say that the inspiration for my solution came from watching a very cool video about a company called Obleeek Objects. Alas, I can not find their website or I would reach out to them and thank them. Check out the beautiful work he does in this fun video.

What I learned from watching this video was that he pours upside-down. As an experiment, I decided to take one of my Tupperware containers and modify it so I could make a tea light. Here is the finished product. The top, while bubbly (more on that later) is smooth and required no sanding. The bottom required a light sanding but no one sees the bottom of pots, or tea lights, so that really does not matter.

Here is how I did it. I used an IKEA container, some plastic tea light candle shells and some nuts, washers and bolts.

I drilled holes in the top of the container and also through the plastic shells then bolted that all together like this.

Next I cut a hole in the bottom of the container and then snapped the lid back on like this.

I applied a release agent (mineral oil) to all the surfaces and then poured the concrete into the mold. When it was cured, I removed it all from the mold, gave the bottom a light sanding and placed some candles in the holes. Here is another image of the finished product.

Not bad for an experiment! The groove around the top is formed by the connecting point of the lid and the bottom of the mold. While it’s interesting, I wanted to try again and end up with a smooth side wall. How to do it?

I decided to try a silicone cookie sheet. Yep … you read that right. I used the same bits and pieces and the bottom part of the IKEA container and a piece of plywood. I drilled holes in the plywood and into the silicone cookie sheet.

I then threaded the plastic shells through the cookie sheet and plywood. Then I used the wing nuts to tighten them down to the cookie sheet … like this. This makes for a very tight fit that the concrete can not penetrate.

The bottom of the container was then centered over the 3 plastic shells and clamped down using a clamp I created out of some scraps of oak, a few bolts and more wing-nuts. Here is what that looks like.

The concrete is then poured into the mold and allowed to set.

Here is the final product. Smooth walls and top … but still bubbles, which it turns out, folks like anyway! LOL

Here is a side-by-side of the first and second attempts.

Having completed this test, I decided to try using this idea to create the same concrete pot I showed you in the previous post. I used the same IKEA containers that I used to create that pot. This time, the smaller one was bolted through the silicon and plywood and the larger one placed on top and clamped down (basically, the same as the tea lights shown above).

Here is the result: Lovely, if I may say so myself! Note the smooth edges, walls and lack of bubbles.

Getting rid of the bubbles was simple enough. I mixed the concrete, and then before I poured it I tapped the bucket on the floor about 20 times, then tapped the sides of the bucket. I then let it sit for about 3 minutes. You can see the air releasing from the surface when you do this. After I poured it, I tapped away on the sides of the mold and also used a rubber mallet to tap on the plywood all around the mold. Lots of air bubbles were released. A simpler way would be to buy a concrete vibrator.

What I learned and what I want to learn

Silicone sheets are a great solution and lend themselves to all types of molds.

Spend a bit more time on the mix and tapping to get rid of air bubbles.

Tupperware and IKEA containers are very, very versatile.

For example, meet Ying and Yang! Solid domes. Paperweights? A bubbler for an indoor water feature (if they had a hole through the center)? They are quite zen, actually. Folks love to touch them! I’m NOT making that up either …

What’s next?

In the next post, I will show you the next version of my mold, which produces some beautiful rectangular concrete pots. See you then!

Read more in this series:

Part 2 – Concrete Creations: A Thinner Mix

Part 4 – Concrete Creations: A Configurable Mold!

Photo Credits

All photos by Gil Namur – All Rights Reserved

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