Laser cutter from HPC

It's been a busy couple of weeks, with "real life" taking over for a while (always the case, as summer approaches, family holidays are arranged, lots of doubling up at work covering for colleagues who are lucky enough to take their holidays before the schools break up and so on).

As work on the touch-sensitive range of instruments stalled, due to cutting problems, we decided to take the plunge and make a heavy investment. In fact, we're making quite a few BIG investments at the minute, the least of which is taking out a lease on a shop to sell homewares, home-made goods and generally supporting the whole maker/cottage industries that are slowly but surely growing throughout the UK. As well as buying stock in, I've got a crazy idea about selling make-it-yourself kits and pre-assembled "geeky gadgets". And the first range of products? Yup. Miniature instruments.

So making them from MDF seems difficult due to the limitations of the CNC, what's the alternative? Acrylic of course! You can see where this is heading....

...HPC in Halifax supply laser cutters. And we're the proud owners of a shiny new LS3020 machine. We spent the day up there recently and saw one in action. It was amazing - blasting through 6mm acrylic in a single pass with no problems, cutting mdf, laser ply, and even solid maple, all 6mm thick, in a single pass at varying speeds (the slowest at around 8mm/sec cut 4 layers for an entire guitar in just a few minutes). Exciting stuff!

After getting everything set up and following the instructions and advice very closely, we're almost ready to cut. The only thing is, this is an expensive bit of kit, and very easy to get wrong (and break �150 CO2 tubes apparently). So we're a bit nervous of actually firing the thing up on our own!
The thing is, the CO2 tube had some air bubbles in it even after the machine had been switched on (with the water pump running) for about half an hour. We got rid of the big bubbles that had collected at either end, by tipping the machine then pinching the water inlet pipe for a second or two and releasing (returning the machine to horizontal). This worked really well for getting rid of the "air locks" in the tube.
completely air bubble free water jacket around the CO2 tube

The worry thing is that the main part of the tube has a lot of little tiny weeny bubbles along its length.

smaller than the bubbles in a Wispa bar, are these anything to worry about?

We've tried all manner of stopping and starting the water flow, tipping the machine, leaving it to rest, turning it off and going for a walk, switching it on and moving it around. It doesn't matter what we do, those little tiny bubbles don't want to go! The question is - can we run the machine with these little bubbles? Do they matter that much? Not knowing enough about it, we're frightened to fire the machine up fully and try cutting, just in case the tube gets busted. That'd be a real bummer. The machine's only a few days old; we don't want to break it before we get started!