JimGnitecki
Active Member
Yes, I predicted the outcome right from the start of the video. The combination of cost and time to reduce the sound level at consumer level is impractical. Plus, he did not mention it, but all the restrictions he added on inatke and exhaust to silence the noise also made it much harder for the compressor to suck in air, AND if that computer fan fails, he'll overheat the compressor pretty quickly. There might even be potential to start a fire. And of course, all these undesirable outcomes are invisible to the user until they manifest in degraded performance or costly failures.
Putting an air compressor outdoors is also not a good solution. That will expose the compressor to weather that will degrade it over time, and will also make it pretty vulnerable to theft. And, any neighbours, whether residential or commercial (anything sbort of industrial) are going to be VERY unhappy.
Face it: compressors are a necessary or desirable thing but are costly and head-rattling loud. if you seek out a quietER one, you will pay more and get less performance, and it will STILL require hearing protection unless your shop is (very) large enough to enable isolating the sucker. And isolating it (as the guy in the video did) unfortunately masks symptoms of its distress when something goes wrong to the point that serious damage could occur to the compressor or to your shop.
In my own case, I have successfully avoided, up to now, creating a NEED for having more than a pretty small and relatively inexpensive one. Topping up my vehicle tire pressures (a truck, a car, a motorcycle, and a small trailer), and feeding my finish nailer, are VERY modest loads for an air compressor. Long bars, the most powerful electric impact tools, and strong electrical power tools have made getting a bigger, louder compressor unnecessary. My radial arm saw, my planer, and my circular saw have been the loudest tools in my shop, but their use is intermittent, not constant, and ear muffs work.
But I underestimated the amount of air that is needed to feed a plasma cutter. I was fooled by the modest PRESSURE requirements that the seller's ad touted, and did not see the CFM statement until I had the machine and its user manual in hand, and found the 6 CFM requirement buried on page EIGHTEEN of the manual, where the manufacturer also confessed that it is probably a good idea to have a notable amount of extra CFM in some situations. One of you on the forum drew to my attention for example that the AFTERflow required on a plasma cutter is often as long or longer than an individual cut uses! So, repetitive short cuts become repetitive LONG CFM consumers.
It would be nice to be able to build up the psi and CFM in advance in a lengthy but quiet process using a small, quieter, and much less costly air compressor. But the math really really works against that. A 20 gallon air tank holds only 2.7 cubic feet at say 125 psi, which you'd consume in a fraction of a minute of plasma cutting. Even a 100 gallon tank holds only 13.5 cubic feet at 125 psi. If you start drawing even the 100 gallon tank down at a rate of 6 CFM at just 50 psi, you'll blow through it ENTIRELY in at MOST 13.5 / 6 x 125 / 50 = 5.6 minutes!
What about renting or buying a large compressed air cylinder? The largest one that Air Liquide apparently offers here in Canada is 230 standard cubic feet. That's 230 / 6 = only 38 minutes of 6 CFM air. I have no idea what an air delivery costs for such a cylinder. At a cutting rate of say 20 inches per minute, that would be 760 gross inches, but actually the NET inches would be far less because of the afterflow requirement.
For example, on 3" cuts, you'd be actually cutting for only 9 seconds, but a 15 second afterflow would mean you'd use up 24 seconds of air or about 2.4 CFM. At that rate you'd burn through the entire cylinder of compressed air in 96 cuts. If you were doing 12" cuts, you'd use up the entire cylinder in 45 cuts (more "efficient" than the 3" cuts because the afterflow remains the same). But at least the air supply would be QUIET versus ear damaging and stressful and annoying.
But, as I said, I have no idea what a 230 cu ft air refill delivered costs (delivered because the tank is too large and heavy to take in to the air supplier).Ironically, plasma cutters themselves are getting very inexpensive, but the air to FEED them, properly, appears to be surprisingly costly in terms of either money and/or noise and stress.
Jim G
