Published on 10/18/2026 · by Leandro Caldas, glazier, founder of Routeck and creator of the Arena
Mirror cutting machine: the EP3 shape in about 1 minute
In Arena do Vidro EP3 the contestants had 20 minutes to copy a mirror shape without touching the template, cutting by hand with no edging. While they measured, transferred the drawing and scored, I told the truth on camera: on the Router Glass, cutting it myself, it would take me about a minute.
This post is the story behind that line. It's not to take anything away from what Rômulo and Janael did, because cutting that shape by hand, under pressure and with cameras on you, is genuinely hard. It's to show, step by step, where the 20 minutes go when you cut by hand and why they almost disappear on a mirror cutting machine.
Where the 20 minutes go when you cut by hand
Anyone who watched the episode saw it: the cut itself is the quick part. The time goes before the cut. To copy a curved shape without touching the template, a glazier has to measure, find reference points, transfer the drawing onto the mirror and only then score. Every curve copied wrong turns into a gap the judge measures with calipers.
| Step | By hand (EP3) | Router Glass |
|---|---|---|
| Drawing | measure the template and transfer it to the mirror | the shape is already a file |
| Scoring | freehand, curve by curve | the machine follows the drawing, ±0.5 mm |
| Mirroring | depends on whoever draws it | the file is the same either way |
| Time | a 20-minute challenge | about 1 minute, per Leandro in the episode |
| Break-out | an uneven score raises the risk of cracking | continuous score, even pressure |
What went wrong in EP3, and what the machine fixes
Both mistakes in the challenge are exactly the ones a machine takes out of the equation. Rômulo's mirror cracked on the break-out: he cut closer to the template, but the piece split. Janael flipped the drawing: the piece came out, but mirrored the wrong way relative to the template. Janael admitted it himself during the challenge: he said he's terrible at manual work.
- Cracking on the break-out: on the Router Glass the 145° carbide wheel scores with steady pressure from start to finish, with no weak stretch for the crack to run off.
- Wrong mirroring: the shape comes from the file, so there's no way to draw it flipped by accident.
- Gap from the template: the machine cuts the drawing with ±0.5 mm accuracy, the same on every piece.
- Time: the measuring and transferring time is gone, because the drawing is already in the software.
The challenge ended in a tie: one got close and cracked, the other didn't get close. In a real glass shop, that's two pieces to redo and two more sheets on the bill.
What this changes for a glass shop owner
In the Arena, the clock is 20 minutes. In a glass shop, the clock is the customer's order. Mirrors with organic shapes, curves, notches or cutouts are the pieces that sell best and lose the most money when they're made by hand. Every cracked piece is a lost sheet, and every hour spent drawing is an hour not producing.
With the Router Glass, a glazier draws once and cuts as many identical pieces as needed. The machine cuts glass and mirror up to 10 mm thick, at 8,500 mm/min. Hand skill still matters, especially in edging and finishing, but cutting the shape stops being the step that holds up the job.
- How long would the EP3 shape take on the Router Glass?
- In the episode I said that, cutting it myself on the Router Glass, it would take about a minute. In the challenge, the contestants had 20 minutes.
- What happened to the contestants in EP3?
- Rômulo's mirror cracked on the break-out and Janael flipped the drawing. The judges called it a tie.
- Does a mirror cutting machine replace the glazier?
- No. It takes over transferring and scoring the drawing. Measuring with the customer, edging, installing and finishing are still the glazier's job.
The full EP3 is at the top of this post. And if you want to see the machine cutting the same kind of shape, the link is right below.
Full episode 3 · Cutting a mirror by hand with a template: the EP3 challenge · Router Glass