If you've got an early ChalkBlaster, look at the brush head. The bristles are split down the middle by a channel. That channel was our proudest idea. It's also gone, and your brushing got better the day we removed it.
What brush V1 was trying to do
The idea behind ChalkBlaster brush V1 was obvious once you thought about it. The jet fan pushes air through the handle, so why not run that air through the middle of the bristles and blow it straight onto the hold? We machined a custom air channel that split the bristle pack in two. Air came out exactly where the bristles were scrubbing. Unique design. Looked clever in the photos. We thought we were geniuses.
Then we built it in volume. The split insert was expensive to manufacture, the production steps were complex, and in use the air was slowed down by the bristles it had to push through. The one thing the channel was meant to do, deliver fast air to the hold, it was doing worse than we expected.
What we did instead: strip it all back
Brush V2 is a simple, symmetrical bristle insert. No channel. No clever geometry. A standard form that's easier to manufacture and cheaper to make. Because it's symmetrical, you can pull it out, turn it 180 degrees and click it back in, which gives you two fresh leading edges and roughly twice the life from one head.
We expected to lose a bit of clearing performance and win it back on cost and durability. That's not what happened.
Why the simple head clears chalk better
With the channel gone, the air from the jet fan has nowhere to go but around the outside of the bristle pack. It leaves the handle at high speed and hugs the sides of the brush head. Fast air moving along a surface pulls the air next to it along too. That's the Coanda effect, the same thing that makes a stream of water bend around the back of a spoon.
On ChalkBlaster V2, that wrapping air creates suction underneath the bristles. Instead of blowing chalk around from above, the brush lifts it out from the hold surface as the bristles loosen it. Chalk leaves the hold faster than our "clever" split channel ever managed, and the air never has to fight its way through bristles to get there.
Blows straight onto the hold
Air slowed by the bristles
Expensive, complex to produce
One wear edge
Air wraps the sides at full speed
Coanda suction under the bristles
Standard form, lower cost
Rotate 180 degrees, 2x life
What this means on the wall
Your ChalkBlaster clears a greasy sloper faster with the plain head than it ever did with the fancy one. The head lasts about twice as long before you replace it, and replacements cost less because they're simpler to make. Fewer parts, less money, better friction on your project. That's the trade we'd take every time.
The lesson stuck with us for V2 of the whole tool. The best design is often the one you almost dismissed for being too simple.
Paul: "We thought we were geniuses. Then we stripped it all back. Performance actually improved. The Coanda effect creates suction under the bristles and removes chalk better than our clever design ever did."
Quick answers
I have a V1 brush head. Should I switch?
When it wears out, yes. The V2 insert fits the ChalkBlaster head and clears chalk better. Until then, keep brushing.
How do I get the second life out of a V2 head?
When the leading edge of the bristles starts to flatten, pull the insert, rotate it 180 degrees and click it back in. The fresh edge is now at the front.
What is the Coanda effect, in one sentence?
Fast air moving along a surface pulls the air beside it along, which on ChalkBlaster V2 creates suction under the bristles and lifts chalk off the hold.
SWEEP Climbing builds tools for climbers who take friction seriously.
