Author Topic: Modified compressor.  (Read 4724 times)

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Offline davelectronicTopic starter

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Re: Modified compressor.
« Reply #25 on: March 31, 2021, 09:54:59 am »
The oil a purchased is in the image below, I was going on the ISO 64 standardisation. So is that oil not suitable ? I did find an oil product Bambi compressors use, but the same oil, but generic so not a named brand. It was twice as expensive as the oil in the picture, that was purchased off Amazon.
 

Offline BradC

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Re: Modified compressor.
« Reply #26 on: March 31, 2021, 11:31:29 am »
The oil a purchased is in the image below, I was going on the ISO 64 standardisation. So is that oil not suitable ? I did find an oil product Bambi compressors use, but the same oil, but generic so not a named brand. It was twice as expensive as the oil in the picture, that was purchased off Amazon.

No, that oil is fine. It's a refined paraffin not a POE. You said you'd bought Polyolester, but that isn't.
 
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Offline davelectronicTopic starter

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Re: Modified compressor.
« Reply #27 on: March 31, 2021, 03:30:12 pm »
Oh ok, I must have got it wrong. I've looked at so many different oil types, I know it can't be as viscose as 10W 40 engine oil. The polyoester oil idea was just what I'd been reading on general functioning of hematically sealed compressors. If it's the right oil that's great. I've run into some mounting to the air receiver, with the position both compressors sit at. Got to get a larger plate to mount them on. Current configuration leaves it to unbalanced with weight to much to one side. Going with longer threaded rod M10 and get them centred above the receiver. And a hose thread to receiver is being difficult, I though it was 1/4 bspp female. That doesn't fit, 1/4 npt doesn't fit, I can only imagine it's 1/4 unf maybe.
 

Offline Refrigerator

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Re: Modified compressor.
« Reply #28 on: March 31, 2021, 05:14:23 pm »
I've bought some polyoester oil ISO 64 I found a data sheet for these compressors, but oil quantity isn't on.

Take it back. It’s terribly hygroscopic and will just turn to acid. Flush it out and replace it with plain old mineral or synthetic air compressor oil. I’d use 4GS but that’s only because I have some. Pretty much any light mineral oil will do.
Plain motor oil should work also, afterall there's neither heat nor combustion in a compressor so it shouldn't degrade.
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Offline davelectronicTopic starter

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Re: Modified compressor.
« Reply #29 on: March 31, 2021, 06:51:40 pm »
The main reason I didn't want to put the wrong oil in was possible motor windings damage. I was finding it tricky to find the exact same oil as when it was a refrigeration compressor. Just filled both compressors to 250ml, no oil spitting. So nudged it up to 300ml in each compressor. If it's to much it will end up in the water trap I've yet to buy. I have waited over 20 years to try silent airbrushing. Over 20 years ago I got started on building a similar compressor, but for one reason or other it came to nothing. Shouldn't take much longer now.

The compressor I purchased as "silent" is not, in terms of garage / workshop compressors it is very quiet. But the oil less unit was over 70db, still to noisy for an apartment with people above and below me. When I purchased it, it was the silent part of the description had me convinced it would be fine. This is not a cheap option, the original compressor was £ 175 and a pair of refrigeration compressors where £ 88 posted. Still the cheapest Bambi compressor is just shy of £400 So if it works out it's not to unreasonable. Just have to mount them, plumb in and wire up.
 

Offline james_s

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Re: Modified compressor.
« Reply #30 on: March 31, 2021, 08:59:20 pm »
You won't damage the windings, just use regular compressor oil. Enamel insulation is really durable stuff, and they don't use different wire for different oil. Also you can get compressors for scrap value or even free if you talk to a HVAC guy. Lots of systems get scrapped when there is nothing wrong with the compressor.
 
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Offline MadScientist

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Re: Modified compressor.
« Reply #31 on: March 31, 2021, 09:04:59 pm »
I have a Chinese dual head airbrush compressor , nice and quite , will support upto 5 airbrushs, was about £120.00 various models from £55, will drive two brushes etc

google  bartsharp

building one from fridges units will never be good
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Offline james_s

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Re: Modified compressor.
« Reply #32 on: March 31, 2021, 09:07:57 pm »
building one from fridges units will never be good

Why do you think that? Lots of people have built compressors with salvaged fridge compressors, they work fine. Why buy something new when you can reuse something that would otherwise go to scrap or a landfill?
 
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Offline davelectronicTopic starter

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Re: Modified compressor.
« Reply #33 on: April 01, 2021, 01:49:08 pm »
I can't see a problem using refrigeration compressors to be honest. I've seen the smaller airbrush compressors on Amazon, with the 3 litre air receivers. I expect they are fine for one, maybe two airbrushes at the same time. But they work exactly the same as the oilless compressor I removed from the unit I purchased. There less powerful in terms of watts and piston displacement. They maybe marginally quieter than the beast I removed from the unit I have. I'd have liked a Bambi 24 litre compressor, I just don't have the extra cash laying around at the moment. This idea is a compromise, but as best to the same as a Bambi compressor, just a homebrew version. I would have liked an oil site glass and oil filler port, but it's not a deal breaker. Any oil loss should end up in the airline trap. I don't expect there will be to much. Nothing mechanical last for ever, but hopefully I can get good service life from this diy variant airbrush compressor. If I can find this thread, once it's functional I will post a picture of it. Thank you for all the help and replys, much appreciated.
 

Offline Berni

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Re: Modified compressor.
« Reply #34 on: April 01, 2021, 04:11:03 pm »
Yep fridge compressors are fine, just do put a oil trap right after the output as over time they put out quite a bit of oil, the stuff is messy and gets absolutley everywhere. I simply 3D printed a 3 or 4 stage vertical oil trap from thigyverse and it works really well, not a bit of oil makes it trough, all of it flowing back into the compressor via gravity.
 
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Offline james_s

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Re: Modified compressor.
« Reply #35 on: April 01, 2021, 08:42:35 pm »
You 3D printed something that you are running compressed air through? That's slightly frightening. Hopefully it's over-engineered.
 
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Offline Refrigerator

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Re: Modified compressor.
« Reply #36 on: April 01, 2021, 08:44:26 pm »
You 3D printed something that you are running compressed air through? That's slightly frightening. Hopefully it's over-engineered.
Check out Tom Stanton and his 3D printed compressed air engines.
I have a blog at http://brimmingideas.blogspot.com/ . Now less empty than ever before !
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Offline Berni

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Re: Modified compressor.
« Reply #37 on: April 02, 2021, 12:04:28 pm »
You 3D printed something that you are running compressed air through? That's slightly frightening. Hopefully it's over-engineered.

The walls are reasonably thick.

I was only using it at pressures up to about 1/4 of a bar so no worries. But i tried testing at much higher pressures just in case by blocking the output and letting the compressor have at it with all it can give. At that point the hose started pooping itself off the output from the pressure, so i held the hose down to prevent it from doing that, that made the pressure go even higher but eventually the hose expanded enough to start leaking around connection point. So it most definitely can hold quite a few bars with no issue. And even so my hoses pop off before it gets there as safety.

If you wanted to approach something like 10 bar tho, then yeah you have to be careful, but at a few bar its no biggie.
 
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Offline james_s

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Re: Modified compressor.
« Reply #38 on: April 02, 2021, 07:51:32 pm »
Ah ok, my air compressor is typically set to around 125 psi, and a refrigeration compressor, if not monitored can produce several hundred PSI in some cases so it's worth being careful. Don't underestimate the amount of carnage you can have with the failure of any sort of pressure vessel. It may not occur to someone that their system is running much higher pressure than yours.
 


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