Make A Straight Cut On A Cylinder: For Concrete Molds

In this tutorial, I’ll guide you through a simple yet effective technique to make a straight and level cut to a cylinder shaped mold for making concrete candles.

And achieving a perfectly straight and level cut is a game-changer when crafting cylindrical molds.

cutting top off of bottle so the cut is straight

Importance Of A Straight Cut On A Cylinder

A plastic bottle with a straight cut being used as a mold to hold concrete for a candle.

A straight cut is more than just a finishing touch; it’s the key to crafting level and flawless concrete pieces. A misaligned cut can lead to uneven edges, leaks, and cracks. To avoid these pitfalls, let’s dive into a straightforward solution.

Materials For A Homemade Straightedge For Concrete Cylinder Molds

aluminum flashing at least 14″ long x 2″ wide. This comes in rolls at home improvement stores if you can’t find a piece longer than 14″.
Blue tape
Utility knife

Steps For Making A Straight Edge For Cylindrical Concrete Molds

Step 1. Trim The Flashing To Size

First, cut the aluminum flashing to a size of 2” x 14”.

The factory edge is always a true straight cut edge, so it’s important to distinguish it. So mark the uncut edge (factory cut edge) to distinguish it from the other side.

a piece of aluminum cut into a rectangle with blue tape along the long edge

Now run a strip of blue tape along the non-factory cut edge, ensuring overlap on both ends.

Tip: This homemade straightedge can be reused 15-20 times before needing a replacement.

Step 2: Cut the Cylinder with the Straightedge

Measure and mark the desired height on the cylinder (e.g., 3″). This number will come from the concrete candle tutorial you are following.

Place the tube on your table and with a ruler, measure from the table up the cylinder and mark it at 3″. Now measure this in three more locations around the tube and mark them.