Nobody tells you that 12 parts can take six months.
That's what it took to go from our first ChalkBlaster prototype to a pre-series unit ready to ship. Twelve components. Half a year. Hundreds of decisions on design, performance, ergonomics, scalability, and cost — and roughly seven major redesigns in between.
It sounds ridiculous when you say it out loud. But that's what happens when you're genuinely chasing the best version of something, rather than just the fastest version.
Where it started
The first prototype was rough. It worked — in the sense that air came out and chalk moved — but almost nothing about it was right. The materials weren't durable enough. The form factor was too bulky. The cost of components would have made the retail price unworkable for anyone who actually climbs for a living.
So we redesigned. Then tested. Then found the next problem. Then redesigned again.
Early prototypes vs later. At first stage everything was 3D printed and nothing was optimised.
The hardest constraint: three things at once
The engineering problems were solvable. The real difficulty was that we were trying to optimise for several things simultaneously, and they kept pulling against each other:
- PerformancePowerful enough airflow to actually lift chalk from micro-texture — not just move it around on the surface.
- DurabilityIt needed to survive chalk dust, outdoor humidity, drops, and the general abuse that climbing gear gets.
- CompactnessA tool climbers won't leave at home because it's too awkward to carry to the crag.
- PricePremium enough to be taken seriously. Accessible enough that it's not just a piece of novelty gear for people with money to burn.
Every iteration meant killing an idea we liked. Every choice meant trading one priority for another. That's the honest reality of building hardware — you don't get to optimise for everything at once. You have to decide what matters most, and commit.
Bootstrapping the build
We couldn't afford custom injection moulds at low volume. We couldn't afford dedicated electronics or fully optimised assembly lines. So we 3D printed almost everything in the early stages — FDM first, then MJF for better surface quality and mechanical properties — and assembled every single unit by hand.
The process was slow. Nothing was optimised. Every step took longer than it should. But there's something important that happens when you're forced to assemble your own product manually: you find every flaw.
The bootstrap paradox
There's a paradox at the centre of bootstrapping hardware that nobody warns you about clearly enough. Better manufacturing requires capital. Capital requires sales. Sales require a product that's good enough to sell. And getting the product good enough means investing time and money you don't have yet.
The way through it is iteration — tight loops, real-world data, constant improvement. We filmed every assembly session so we could calculate time per station later. We documented every failure mode. We didn't stop to make it perfect because perfect doesn't exist until you've broken something at least three times.
What six months actually taught us
Working for clients in mechanical engineering, you solve a clearly defined problem inside a fixed scope. Cost, risk, and timelines are mostly abstract. You hand over deliverables and move on.
Building your own product is a completely different experience. Every decision has a real cost impact. MVP means cheap, fast, and imperfect — and that's not a compromise, it's a strategy. Iteration happens in public, with real users watching. Supply chains push back. Cash flow dictates your roadmap whether you like it or not.
What we learned is that the gap between "prototype that works" and "product that ships" is larger than almost anyone tells you. And bridging it is slower, messier, and more expensive than any timeline suggests. But it's also where the product actually becomes good.
The result of 6 months, 7 redesigns, and more broken prototypes than we'd like to admit.
See the ChalkBlaster →Frequently asked questions
How long did it take to develop the ChalkBlaster?
Six months of active development from first prototype to pre-series unit, with seven major redesigns along the way.
How many parts does the ChalkBlaster have?
The ChalkBlaster is a 12-part assembly. Each component was chosen to hit the right balance of performance, build quality, and cost.
Is the ChalkBlaster made with 3D printed parts?
Early prototypes and the pre-series used 3D printed parts — FDM first, then MJF. We are currently redesigning for injection moulding ahead of mass production.
Who built the ChalkBlaster?
The ChalkBlaster was co-developed by Kent Eskildsen and Paul Ménager under Sweep Climbing, bootstrapped from a workshop in Denmark. Every unit in the pre-series was assembled by hand.
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