Author Topic: Air Compressor  (Read 2585 times)

Offline vcutajar

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Air Compressor
« on: August 18, 2014, 10:30:07 PM »
Hi guys.

Now that the Corliss is nearly ready I have decided (finally) that I need to get myself an air compressor to run it with.

I have never owned or operated a compressor before so this will be new territory for me.  I have done a little internet research and have done a little window shopping.  There are a lot of relatively cheap Chinese units around but I have laid my eyes on a couple of Italian FIAC models reason being that I can get a discount and also spares are not a problem.

They are both exactly the same specification except that one has a 25 and the other has a 50 liter reservoir.  So the question (finally) is what difference does it make having a larger reservoir?  Will the compressor with the larger reservoir start and stop less often when compared to the smaller one?

The compressor will be used to run these model engines, inflating an occasional tyre and maybe for blowing air for cleaning purposes.  Which one should I choose?

Thanks

Vince

Offline mklotz

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Re: Air Compressor
« Reply #1 on: August 18, 2014, 10:48:29 PM »
If you're using it to demonstrate engines, pay close attention to the noise level of all you're considering, most especially if they're oil-less.  Trying to talk over a thumping compressor gets old in a hurry.

I don't know if they're available in Europe but perhaps include the California Air Tools 1610-A in your choices.

http://www.californiaairtools.com/

Watch the noise comparison video on their page.  It illustrates my point about noise.

If your engines are relatively small (e.g. Elmer size), an airbrush compressor works very nicely indeed and they are super quiet though they certainly won't inflate tires. 

A water trap is essential if you want to avoid rusty engines.  (Many airbrush compressors come with one built-in.)

I don't like the idea of blowing dirt around the shop with a compressor.  Get a shop vac; they're useful for other purposes as well as cleaning.
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Offline Jim Nic

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Re: Air Compressor
« Reply #2 on: August 18, 2014, 10:55:44 PM »
Hi Vince
The larger reservoir will indeed mean that the compressor will cycle less often BUT it will also mean that the time taken to bring the reservoir up to cut off pressure will be doubled.  You may wish to take a couple of other things into consideration such as the rate of free air delivery of your chosen machine.  If your engine is using more air than the compressor is delivering to the receiver (tank) then it will be running almost constantly in an effort to keep the receiver charged.  Another consideration is the noise level of the running compressor.  My own device, a cheap machine bought with more than half an eye on the cost, is horribly noisy to the extent that as soon as funds permit it will find itself out of a job in favour of a quiet device.
Jim
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Offline philjoe5

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Re: Air Compressor
« Reply #3 on: August 18, 2014, 11:48:19 PM »
A quiet air compressor may cost a bit more but will reward you every time you use it.  Marv's recommendation is covered in this recent thread:

http://www.modelenginemaker.com/index.php?topic=4001.0

Cheers,
Phil
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.  - Mark Twain

Offline mklotz

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Re: Air Compressor
« Reply #4 on: August 19, 2014, 12:17:29 AM »
My apologies, Phil.  I had completely forgotten that I had read about the compressor in the thread you referenced.  Getting old really sucks!  :old:
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Offline philjoe5

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Re: Air Compressor
« Reply #5 on: August 19, 2014, 02:37:11 AM »
Marv,
I believe apologies become unnecessary after age 50 :LittleDevil:  At least, that's MY story and I'm stickin' to it!

Vince,
Get a good compressor.  I'm sure you'll get a lot of use out of it.  I started out small and kept buying up.  Kind of like machine tools, boats, cars, bottles of beer, etc. :ROFL:

Cheers,
Phil
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.  - Mark Twain

Offline fumopuc

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Re: Air Compressor
« Reply #6 on: August 19, 2014, 12:11:30 PM »
A quiet air compressor may cost a bit more but will reward you every time you use it.  Marv's recommendation is covered in this recent thread:

http://www.modelenginemaker.com/index.php?topic=4001.0

Cheers,
Phil

Yes Phil, hundred procent agreed.
 
Hi Vince, to run my modells I am using a self made compressor with two compressor units from old refrigerators and a gas bottle as a reservoir. This unit was build very professional by an other model engine maker. I have had the luck to get it for a very good price and I never want to miss it anymore. All other solutions before have been a noisy night mare in the workshop. If you want to spend some relaxing hours in your shop, fiddling around and your current model is at the 4 hours running in period under observation, that will be latest the moment you will remember this posting.
 
Kind Regards
Achim

Offline Ramon

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Re: Air Compressor
« Reply #7 on: August 19, 2014, 01:05:15 PM »
Hi Vince - just to add to the valid comments on noise. My second compressor with small volume tank(reservoir) was constantly cutting in to recharge. Although it only used to take just over a minute to top up the noise was horrendous and would drown out everything. Still working fine I parted with it when the volume tank perforated on the end.

Thinking ahead that I would want to use it for bead blasting where lots of volume is required I replaced it with a much larger one with as large a volume tank that I could afford. The benefits were immediate - for basic workshop air - cleaning parts, tapped holes and the like it only needed charging once a week  :o  - and the noise level reduced to 'being able to carry out a conversation beside it whilst running'. It's very much a question of 'yer pays yer money etc.' Like Marv says though if you only want to run the odd engine then maybe a small diaphragm type (but IMO it does need to be larger than an airbrush type) may be all you need. I began with one of these - putting out about 35 psi max it carried out all my spraying requirements on aircraft with ease - would run all the engines I had without 'gasping' and was comparatively quiet - certainly quiet enough to have by the bench. It did not have a volume tank so I created one from two large plastic lemonade bottles - the pressure test that these have to pass far in excess of anything a diaphragm compressor will put out. It was no use for pumping up tyres though.

Hope that adds a little more

Regards - Ramon
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Offline arnoldb

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Re: Air Compressor
« Reply #8 on: August 19, 2014, 07:51:53 PM »
I agree with the "noise" comments... 

My small compressor (50l tank, 50l/minute) used to be fairly quiet when it kicks in, and is perfectly suitable for running engines and inflating a tire when needed, but doesn't supply adequate air volume for spray painting with a bigger spray gun, or for using air tools.  It's in need of some TLC though; the con-rod bearings are worn and starting to slap a bit, so I've not used it much in the last two years.

I bought my "large" Chinese compressor as large as possible for my single-phase supply (200l tank and 250l/min)  to operate air tools and eventually use it for small sandblasting jobs; for this one needs high volume airflow.  With the smaller compressor a bit sorry for itself, I've been using the big one to run engines, as well as provide airflow while milling small slots on the mill to blow chips out.  The problem with using it in a low-volume scenario like this is that one forgets that it's on and slowly running out of air...  It has a tendency to "know" when I'm really focussed and concentrating on a delicate piece of work or trying to get that final fine-tune on an engine - and it chooses that point to loudly start up.  This has on many occasions nearly made me cr@p myself and throw tools every which-way or yank on a feed wheel...  My shop is normally dead quiet, with only the machine in use, if machining, making a noise, so the sudden unexpected loud start is seriously disconcerting.  In fact, I'm going to move the big compressor out of the shop completely and lay on permanent air plumbing and a remote on/of switch for it because of this.

The only disadvantage to having it outside of the shop, is that one will be inclined to forget about regular inspections, so I'll add it to my "safety inspection" reminder list.  Compressors do need maintenance and inspection, and I've met many people who didn't know that one's supposed to drain the air tank of water and check the oil level on a regular basis...

So, once again, it all comes down to what you need, but if you're going to keep your compressor inside your shop or want to use it at odd hours in a residential neighbourhood, I'd definitely also recommend a quiet one!

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline smfr

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Re: Air Compressor
« Reply #9 on: August 19, 2014, 08:48:27 PM »
I don't know why compressors don't have a little "warning" click or beep before they kick in.

Simon

Offline vcutajar

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Re: Air Compressor
« Reply #10 on: August 25, 2014, 03:48:10 PM »
Thanks guys for all the suggestions and tips.

Today I went out and got me the 50L Italian model and a German accessory kit to get me started.  Read the instructions, started it up and waited for it to build up pressure.  After a couple of minutes and the pressure still reading zero I was starting to panic (remember I never had a compressor).  Should it take this long?? :'(

Eventually, I switched it off and as soon as the noise stopped, I thought I heard air leaking from somewhere.  After some investigation it was found that the drain valve at the bottom of the tank was open. :facepalm2:

Vince


Offline philjoe5

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Re: Air Compressor
« Reply #11 on: August 25, 2014, 06:34:56 PM »
Quote
After some investigation it was found that the drain valve at the bottom of the tank was open. :facepalm2:

Vince,
Don't feel bad about that, at least you discovered it.  My friend went to a "scratch and dent" sale that a local hardware store was having.  He saw a compressor much like yours on sale with a sizable discount.  He took it home, started it and heard the air coming out of the drain valve.  He closed the valve and it worked perfectly. 

Good luck, it should handle your models just fine

Cheers,
Phil
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.  - Mark Twain

Offline arnoldb

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Re: Air Compressor
« Reply #12 on: August 25, 2014, 07:21:10 PM »
Nice one Vince  :ThumbsUp:

At least you know the tank is well-drained now  ;)

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline Ramon

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Re: Air Compressor
« Reply #13 on: August 25, 2014, 11:26:34 PM »
Glad you got sorted Vince - steep learning curve on that one eh? ;)

Not long before that first run on it either  :ThumbsUp:

Regards - Ramon
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(a very apt phrase - thanks to a well meaning MEM friend)