So, after my jury-rigged twin compressor arrangement suffered a fatal compressor moment, I needed a new compressor.
Rather than go for another jury-rig arrangement (a 50L and a 75L compressor running in parallel) I decided to go for a full-on grown-up 100L twin piston jobbie. After hunting around ebay for a bit, I found the compressor I needed. I had to move up the rankings because I needed to spray a lot more. My previous arrangement was kinda ok for soda-blasting but even then, I had to stop relatively frequently and let the tanks recharge so I had enough pressure. This compressor can provide the air I need to continuously spray or blast.
However, it is loud and large. So large, it won’t fit in compressor-corner where the others are, even if I evict them like a set of victorian tenants that don’t pay their rent. So, I decided to box it in and add sound-proofing to reduce the noise.
Here is the boxed in compressor, utilising several kitchen cupboard doors from my friendly cabinet maker (who had removed them from a job he’d done fitting a bespoke kitchen). Being the scientist I am, I took a few reading for loudness. Before building the workbench, I took a reading on my iPhone 1m away from the centre of the compressor to the normal of the length of the tank, it was reading 92dB.
After adding the bench and boxing everything in, it actually went up 1dB which didn’t surprise me – I’d basically put a sound-source inside a large sound-box.
This is the insulation I used – it’s the cheapest recycled stuff I could get from B&Q, and I spray-tacked it to the inside. I didn’t have enough to do all the outward facing surfaces and the underside of the bench as well, but I may get more … this will be decided after I reveal the new amount of quietness.
Here’s the shot from the inside going down the bench. You can see just how much volume the insulation consumes.
So, why did I do this, and what was the result?
Why was easy – I tend to work on the car late at night, and I don’t want to disturb the neighbours. Furthermore, when I’m working in the garage, I don’t want to involuntarily evacuate every time the compressor fires up, nor do I want to work in the garage wearing ear-defenders all the time.
The result was brilliant – I have taken the sound-levels down from 92 dB to 82. This is significant, bearing in mind 10 dB is 10x the power. It’s not 10x the loudness of course.