THE BRUSH BLOG

Stories, gear & friction.

Field notes, build logs, and everything we learn making climbing tools.

Broken motor blade of a high-powered BLDC motor for Jet fan devices.

What a 150,000 RPM motor failure taught us about your ChalkBlaster

A stock motor spinning at 150,000 RPM lost three blades on our bench and destroyed the unit around it. Here...

Jun 15, 2026
AI generated picture of rock climbing fans and jetfans

Fans, leaf blowers, and where a jet fan fits in bouldering

Climbers haul box fans and leaf blowers to the boulders for a reason. Here's what a fan does well, and why ...

Jun 08, 2026
ChalkBlaster boxes sitting on top of bambulab 2PS 3D printer

What our first production batch taught us that CAD couldn't

Building the first ChalkBlaster batch by hand was chaos. It also taught us things six months of CAD never c...

Jun 06, 2026
The ChalkBlaster in the frame with a majestic sunset in the background.

Climbing Brushes: The Complete Guide to Choosing and Using One (2026)

The complete climbing brush guide: how bristles, size, and technique decide your friction, how the climbing...

Jun 03, 2026
Half assembled chalkblaster on a wooden table with brushes laying around.

We Built It Wrong the First Time. Here's What Changed.

The first ChalkBlaster production run was slow and chaotic — on purpose. It exposed what CAD never could. B...

Jun 03, 2026
The Part That Took 15 Tries

The Part That Took 15 Tries

The angle-adjustment system on the ChalkBlaster brush looks simple. It took 15 versions to get there. Here’...

Jun 03, 2026
How We Make the ChalkBlaster 20% Stronger — For Almost Nothing

How We Make the ChalkBlaster 20% Stronger — For Almost Nothing

The ChalkBlaster is built to be abused — thrown, stepped on, and pushed through sessions that would break l...

Jun 03, 2026
A climber brushing at sunset with the most innovative climbing brush of 2026. This is the perfect gift for the boulder who got everything.

2026 Best Gifts for Climbers: 10 Things They'll Actually Use!

Buying for a climber is either easy or completely baffling. This list cuts through it — 10 gifts that actua...

Apr 24, 2026
Adam Ondra sitting in front a cordless fan during his bouldering session for Emotional Landscape 8C/V15, Photo byMartin Švec

Have Portable Fans for Bouldering Become Mainstream?

Adam Ondra just completed the most dominant bouldering run in recorded history V17 and four 8C flashes in 1...

Apr 21, 2026
Should we ban electric climbing brush at competition?

I Was Banned From Using My Own Invention at a Competition

I invented a handheld electric climbing brush and brought it to the Danish Boulder Cup. An official told me...

Mar 08, 2026
Photo by Wolf Lieff. Super caked climbing hold. Lets make sure to brush after climbing.

Your Hands Are Dirtier Than You Think. The Unwritten Rules of Crag Etiquette.

Everyone brushes before they climb. Almost nobody thinks about what their bare hands do to a hold first. Se...

Mar 05, 2026
A complete tear down of the ChalkBlaster showcasing each parts

We Tried to Destroy our Own Product

We packed the motor with chalk, submerged it, blocked the airflow, and forced it to overheat. If it was goi...

Mar 05, 2026
We Built It Wrong 7 Times

We Built It Wrong 7 Times

Seven major redesigns, six months, and more broken prototypes than we'd like to admit — all bootstrapped fr...

Mar 05, 2026

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