http://hackaday.com/2016/10/12/fridge-parts-make-air-compressor-thats-easy-on-the-ears/
feed this with the main compressor through a check valve… it wouldn’t run much. would be quiet enough to run 24/7 and would probably be fine considering the modest airflow of laser.
I was considering building something similar for my home workshop. thought I’d share.
-D
I have been in search of fridge compressors from scrappers lol. It would be perfect.
What the price and air flow in comparison to a $80 air brush compressor for just the laser? I believe somebody said there was one in storage somewhere, or we could buy one just as easy.
I happen to have a continuous duty, low pressure say about 50 psi pump. It just ran and was not terribly loud. It was for sprinkler stuff, and was salvaged for an airbrush/hobby application before falling into my clutches… er. collected! Yes, collected. If there is interest, I’ll round up some pics or scrounge my glasses and look at specs on it. Looks a bit like a 1/3 hp motor with two pistons attached.
1/3 hp cont duty, reliable model A. 50 psig max, patent 3658350, 746a pump for air, and 78L5 air compressor as markings. I get a diagram of A-2 systems, so… it might be a tad dated for sprinkler systems. Designed system pressure is 30 psi. If my run for large iron tools goes well… I’ll drop this by sometime as thanks to the powers that be.
Cool, I know it is going to be the main issue however CFM is also going to be an issue. I will have to look up what the specs on the way there is for air consumption and make sure we have a system that can keep up with it. I know the guys who run very hot coal furnaces with the fridge compressors and they are next to silent. I know some of the airbrush compressors can get a little louder but we could easily build an enclosure and economical cooling system if needed.
Maybe setting parameters would help. Based on a little research, it seems that most users are confident with 2-2.5 CFM. We could measure this, though.
I suggest aiming for <= 70dB SPL C weighted. I haven’t measured our current compressor. Here are some measurements I just took to give you an idea of what this is. My airbrush compressor = 64 dB SPL C. Printrbot printing = 67 dB SPL C. Typical ambient street noise when indoors in Cincinnati - 55 dB SPL C.
If you add 10 dB SPL C, the sound is perceived as twice as loud. This is the most important factor. Every 6dB is twice as much sound pressure, technically, but it’s about how loud it sounds, not how much air is vibrating…
As a benchmark, this compressor is 70dB SPL C: https://www.amazon.com/gp/product/B00HQYFZGM/?tag=airtools07-20
Not suggesting buying something, but I am suggesting that folks just bring in these compressors to try and see how it goes.
FYI: My basic art airbrush compressor does 1/8 to 1/6 CFM continuous.
Lorin
You might look into California Air Tools compressors. I bought one about 6 months ago and it’s pretty darn quiet. Spec is 60db. They have a whole line of quite air compressors.
Well… the powers that be granted me a successful haul and safe return. Lessons learned: 2100lbs and binders is the absolute theoretical limit of my trailer and truck combination. Offering the powers that be a sacrificial compressor is a good thing. The collets that came with the machine are alone a bargain (specialty unobtainium).
I will try to drop it off/visit Sunday/Monday… likely evening, that is the earliest possible.
It is possible that a manifold and larger filter might quiet the compressor… it has two pistons, 180 degrees opposed.
Awesome we’ll have to check its decibel rating. What’s nice with some of the compressors is if the drive speed is variable you can greatly reduce speed while keeping the CFM needed. Also Heat and a sound proofing box could be very easily made. I made a water cooled jacket for my bigger one in the basement with a cover and it had issues. I have plumbed into parallel compressors from a fridge before and was able to get the operation quieter than what I believe the laser itself would make.
Okay, I can work on sourcing fridge compressors. The recycling center near me has them in those large bulk boxes… volume is about 270 gallons. So, I can grab a few, test at home and return the non working. So, how many do we need? 5 or 6? And what size reservoir are we talking? What tools do we have to test the output?
Because aside from the laser, I would like compressed air, but I hate the noise!
Youre not going to need that many. The flow for the laser is pretty minimal, like single digit cfm if I remember right. 2 or 3 of them 5-10L worth of reservoir would be fine, I’d expect. What’s maximum continuous use time for the laser? Does it have a duty cycle. Use a Hobbs switch to turn them off/on, feed reservoir from main compressor via check valve. I have one sitting around I grabbed from a trashed fridge.
D
uhhh folks? the old compressor for the laser is still here… it’s up on top of the pallets over the electronics area… it’s the one that came with the big Laser.
Why don’t we just use it again? I’m sure we can put a T fitting on it so it can supply both machines.
Cool.
I’ll take a look at it Tuesday night.
Does anyone remember why we switched to the main air compressor?
Brad
probably because it was there?
and it was simpler to have it hooked up when we had the compressor on all the time, no issues with remembering to turn it on.
the air pipe was installed,. and I don’t think we had the noise curfew at the time (no upstairs tenant)
plus I don’t think anyone really realized what a noise problem the compressor would be.
The previous air compressor that ran in the fab lab did not have an air reservoir, so it ran continuously. Also, it was aggravatingly loud. So the entire time you were in there working it was roaring and vibrating away in the background.
The original air compressor came with the “small” laser cutter and was a pretty cheap Chinese no-name device.
Switching to the centralized air made it much, much more pleasant to work in the fab lab, or sit in the lounge, while some one was using the laser cutter.
yeah but this is the one that came with the big laser, I think… So it may be quieter? I am not sure we even touched it when we set up the big laser…
There’s certainly no harm in getting it down and testing, is there?
Good to know.
I’ll take a look at the one we have.
I think we can engineer a quiet system, there isn’t much flow requirement.
I know there are super quiet air pumps out there.
The little compressor was moved to electronics for occasional use with a glue / solder paste dispenser Dave B had at hive. Not needed anymore (we should finish the air line over there, though — for the de solder gun and vacuum tweezers, etc.
From: Paul
Sent: Sunday, May 21, 2017 7:56 AM
To: cincihackerspace@googlegroups.com
Reply To: cincihackerspace@googlegroups.com
Subject: Re: [CHP] Re: Solution for compressed air after curfew for lasers?
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The previous air compressor that ran in the fab lab did not have an air reservoir, so it ran continuously. Also, it was aggravatingly loud. So the entire time you were in there working it was roaring and vibrating away in the background.
The original air compressor came with the “small” laser cutter and was a pretty cheap Chinese no-name device.
Switching to the centralized air made it much, much more pleasant to work in the fab lab, or sit in the lounge, while some one was using the laser cutter.
Lorin… which compressor are you talking about? the one I am referring to is not in use, it is up on the top of the pallet shelving.