What compressor

[Mike BrettParticipant @mikebrett89695]

Hi

I have just built my third stationary steam engine and want to buy a compressor to test and run them. Two are very small and only require about 6 p s i , the third is much larger with a 3 inch piston and would need about, at an estimate, 40 p s i. Could fellow members please recommend what size and model to look for, and what works for them.

Many thanks Mike

[Mike BrettParticipant @mikebrett89695]

help

[JasonBModerator @jasonb]

Quite a big one. I have a 4cfm one with 20lts tank and that is pushed when running engines with a 2" dia piston though at pressures of 10psi or less so your 3" is likely to need double that as a minimum, more if you don't want the motor cutting all the time.

[Frances IoMParticipant @francesiom58905]

Screwfix have a special offer on a 12l compressor 180lt/min (abt 6cfm max 10bar for a penny under ?60 – reasonable size (fits in an 18″ cube but 1.5kw + like all compressors it seem quite noisy – comparable to the 95dBa of my woodworking dust extractor) Axminster sell a supposedly very quiet model but at 6x the price

[MM57Participant @mm57]

I have the Screwfix £59.99 compressor – it does what it needs to do, but you don't want to be in the same room/small shed when it starts up.

[Howard LewisParticipant @howardlewis46836]

All direct drive compressors are noisy!

Belt drive compressors are quieter, but tend to only come in larger sizes, both CFM and reservoir capacity

Diaphragm compressors are quiet, but costly.

If you can stand the noise, I would suggest a 3hp, (probably a V twin) that can be run off a 13 Amp domestic socket.

Even with a 5 or 10 psi regulated offtake, the compressor is likely to cycle on and off fairly frequently, and the sort of units that we buy are not intended for high duty cycles. hence the advice to buy a high delivery machine with a large capacity reservoir.

When I bought my HPC from a local compressor specialist, the advice was to drain down after every use, and to leave the drain open, so that any remaining moisture can escape.

When you drain down, don't be surprised if the air stops escaping with a reading still on the pressure gauge.

The tap will probably have frozen up, with the expanding air bringing the temperature below freezing. Left to its own devices, will thaw and dump the rest of the air and most of the moisture.

Howard

[David lawrence 3Participant @davidlawrence3]

Hi all, We built a sound proof box for our 6 cfm compressor as the noise was so great. drain the tank every day. having a compressor is a great thing to have in any workshop, lots of tools available from blow guns to pop rivet guns. well worth the bother of installing it right, but the noise is a big problem, if you can afford a belt drive its better. as for the very silent types they work well for small loads , cost £ 300.00 or more, they are used mainly for airbrushes and in photo darkrooms for dust blowing but to run a tool or spray gun the cost is very high. david

[Mike BrettParticipant @mikebrett89695]

Hi All

Many thanks for all the replies, just a few points to add. I am buying the compressor solely to run my steam engines ,I do not intend to ever use it with tools. Also I made a small mistake, my largest engine has a 3.25 inch piston. Regarding noise, this should not be a problem as the compressor will be in a different location to my workshop. So I am now looking at a 2 HP 50 ltr job, as I will only want to run the engines under no load conditions and slowly, does this sound about right.

Cheers Mike

[JasonBModerator @jasonb]

What is the stroke?

[Frances IoMParticipant @francesiom58905]

David – interested in your soundproofing – I have one of the cheap Screwfix models but not sure how you can soundproof without running into overheating problems

[Roger Provins 2Participant @rogerprovins2]

Posted by Frances IoM on 10/07/2015 20:10:01:
David – interested in your soundproofing – I have one of the cheap Screwfix models but not sure how you can soundproof without running into overheating problems

I'd also be interested to know what you did. Something I've been meaning to do for ages!

Roger

Edited By Roger Provins 2 on 10/07/2015 20:20:55

[VicParticipant @vic]

I read somewhere that the greatest noise from cheap compressors comes from the inlet and that the noise can be reduced somewhat with the right filter. Don't know if that's right or not but I don't know where to get a suitable filter anyway. If anyone finds out …

[Mike BrettParticipant @mikebrett89695]

HIi

Stroke is 3.25 inches, same as the bore.I will try and post some pictures of it when I have tested it to make sure it actually works. Its an interesting engine in respect of I did not have a lathe when I started it. So the piston cylinder is a length of stainless steel pipe with aluminium plates at each end. The valve is operated by a roller running on a large cam. Seems to work well, when turned by hand, and the compression is very good, just hope I have got the timing right.

Mike

[steamdaveParticipant @steamdave]

Posted by Roger Provins 2 on 10/07/2015 20:20:32:

Posted by Frances IoM on 10/07/2015 20:10:01:
David – interested in your soundproofing – I have one of the cheap Screwfix models but not sure how you can soundproof without running into overheating problems

I'd also be interested to know what you did. Something I've been meaning to do for ages!

Roger

I made a soundproofing cabinet out of 1/2" ply lined with carpet on the 4 sides and top. There is a cutout on the front for the electric cable and airline exit. The cutout is large enough (about 6" x 4&quot for me to get my hand in and operate the switch. Auto drain valve takes care of water when it is shut down.

It didn't take long for the heat to build up in the box so I installed a 4" bathroom fan (40 watts) in the bottom of the front panel and connected separately to a socket. Rear mounted would have been more efficient, but the back and sides of the box are in a recess so no air flow. I can now run the Lidl 1.5 hp compressor for 30 – 40 minutes before it needs to be shut down, which is usually long enough for what I need it for. Noise has been reduced considerably so I don't have to wear earplugs when it is running.

Dave
The Emerald Isle

[VicParticipant @vic]

This may be of use to those planning to build a cabinet.

**LINK**

[paul 1950Participant @paul1950]

One thing to watch out for is motor speed I bought a 3 HP compressor a few years ago that would never keep up with power tools, when I bought it I was told the good thing about it was it ran off a 13 amp plug. The motor has just packed up and I have just fitted a replacement motor. The new motor runs at 2800 rpm and the old one ran at 2680 and was a asynchronous motor that should never be fitted to a compressor as the heaver the load the slower the motor would run. The new motor is almost twice the size and weight of the old one but gets up to pressure in half the time but will not run off a 13 amp plug as one would expect. So keep well away from asynchronous motors.

[Bob Brown 1Participant @bobbrown1]

If building a cabinet do not forget compressors generate a lot of heat so that has to be a consideration.

Bob

[Clive IndiaParticipant @cliveindia]

I think it depends on what output you want and how much use it gets. I just needed air for the bench to spray, clean stuff and drive the odd small engine.

 

I went through the stage of having a high-revving, noisy, direct drive, oil-less, 25L compressor. It provided the air but eventually bust – plastic flaps for valves over hole in the piston. These were replaced but it never quite made it to original output until it went again. It was cheap but did the job.

I looked around and came across a reasonably priced belt-driven machine….

**LINK**

 

I have found it a very good machine for me – not as good as the big boy older types admitted, but it meets my needs and is remarkably quiet compared to the direct drive. I think it will last. OK, it has oil but I can filter it out for spraying. There was quite a bit of prattle about having a dedicated electricity supply because of switch-on surges, although it is well within the 13A rating otherwise. I use it on a standard ring-main socket and have experienced no problems at all.

 

As always, I think you do get what you pay for. If noise is your issue, a sound insulated dog kennel outside or at least housing it somewhere other than the workshop would improve things no end.

Edited By Clive India on 12/07/2015 11:59:48

[paul 1950Participant @paul1950]

It may have an asynchronous motor like mine so it may say 3hp on the label but it will be like having three horses pulling a cart but one facing the wrong way.

[Engine BuilderParticipant @enginebuilder]

I have the same compressor as Clive India and am pleased with it. It is so much quieter than my directly coupled 1.5 Hp Clarke one. Using 15 psi my Clarke, which only has a 6Ltr tank would be running almost continuously.

The Wolf runs for less than one minute and does not restart for about 5 minutes.

[martin perman 1Participant @martinperman1]

I only have a 25 litre tanked compressor which for what I use it for is more than adequate but if I need more air I use a truck compressed air tank which I bought years ago at a steam rally for £15.00, the original idea was to charge it at home and inflate airbeds when camping with my engines at rallies quickly and effortlessly.

Martin P

[paul 1950Participant @paul1950]

What I am trying to say is if its got 3hp on the label and its runs off a 13amp plug its not got the power of a true 3hp if its an asynchronous motor.

[KWILParticipant @kwil]

You could consider a small rotavane compressor like the ones dentists used when the air drills first appeared. So quiet you can leave it running when required.

I have one for my small spray guns and also a 25L "noisy one" for running the tools and auto drawbar on the mill.

[VicParticipant @vic]

Thanks for your comments Clive looks like a nice unit. I'll have to keep a look out for something similar, although I am limited by space unless I put it in a box outside.

[JonParticipant @jon]

Have another branded one of Clives link to get me out the proverbial two years ago.
Tank, motor and pump ok but may need to replace the output side of things I nicked off its predecessor from MMart in 99.

Struggles a bit with air tools and bead blaster even with old tank plumbed in. Point being will pay a lot more for something better and its used daily.

Had 1.5hp some years back ok for blow gun, minimalistic usage air tools its permanently on often having to wait for pressure to build up. Above link is only £70 dearer.

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