albertz
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| posted on 4/4/05 at 07:59 PM |
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Compressor spec.
What is regarded as a decent DIY compressor in terms of HP and displacement?
I interested in buying one, not for any particular job, just cause it will be handy over my lifetime and is a good addition (i am trying to stock a
garage from scratch).
I have looked on Ebay and there are WolfAir 2HP 50 litre (7.16cfm / 215l/min) units going for about 90-100 pound delivered. Is it worth buying one
like that or would i be better saving for something more powerful.
The main consumption units i would be using are likely to be a DA sander and maybe a shot blaster gun, what do they need to run continuously?
Any recommendations, links or advice appreciated. I am in no rush to buy and am just trying to pick up some pointers in case something turns up
locally or whatever - saying that i am the current high bidder on a WolfAir 2HP one on Ebay ......but its early days in the auction.
Any advice gratefully appreciated as always
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ghost_walker
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| posted on 4/4/05 at 08:58 PM |
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you need to know what the most air hungry tool is your going to use and see if the compressor can put out enough air to run that other wise there is
no point
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Peteff
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| posted on 4/4/05 at 09:13 PM |
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Buy an electric sander, quieter and cheaper to run. I have a 3hp 50 litre and a die grinder makes it run almost continuously. I used to use it for
everything but nowadays it's relegated to air chisel and painting work. Fad is what you need, it's usually around 2/3 of the cfm figure.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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clbarclay
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| posted on 4/4/05 at 09:14 PM |
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Fad (free air delivery) is not what you need, as it is measured at 0 pressure. you need sufficient air flow at operating pressure.
[Edited on 4/4/05 by clbarclay]
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RogerM
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| posted on 4/4/05 at 09:15 PM |
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DA sander is just about the most hungry air tool I have come across.
Flat out it drops my set-up to bottom operating limit in less than 1 minute, max usage period is about 2m30s between recharges.
That is impressive whenyou consider I have several reciever units giving 350l plus about another 15l in the pipe main around my workshop. That is fed
by a 14cfm 3HP motor and a reserve pump (which it calls in very early in the game) of 8.2cfm and 2.5HP!!!!
Admittedly when I run it at more 'normal' speeds and loads I get usable service.
The reason for going so big on air power was my fondness of air tools. My die grinder had a duty cyle of about 15s in 3 minutes when used on a 2.5HP
50l unit, now I can do some useful work with it, just about a full cut on a head port ... as in the small amount you remove in one go when
'porting' a head.
Best advice, especially if you are planning on using air as much as lecy power is to save up and buy big. I really should have put a few saved a few
more £££s and gone for the 28cfm unit I wanted (bigest 240V unit I could find).
3HP will probably need to be on something more serious than a 3 pin plug, mine draws 18A on start up.
Just my 2p's worth.
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wilkingj
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| posted on 4/4/05 at 09:32 PM |
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My Clarke Industrial (Hammerite Blue one)15SE/150 (I think) runs everything I have including 22k rpm mini grinders, and my Sand blast Cabinet. but
these make it run almost continuously if used in anger.
Its 3HP, runs on single phase, but needs to be hard wired in, as it will blow a 13Amp fuse on start up (current rush).
14CFM, and 150litre Tank.
Cast Iron Bores.
Cost £400 ish.
Cheaper ones have steel lined cylinders.
Buy as big as you can afford, I have not regretted it one bit.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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Peteff
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| posted on 4/4/05 at 09:51 PM |
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FAD
Is the rate of filling at the compressors maximum output according to my literature, so the higher the FAD the better. If the pump can pump up to 10
bar but only refills the tank slowly you are going to be waiting around for it to catch up.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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albertz
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| posted on 5/4/05 at 06:43 AM |
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So, if i have understood you correctly, the unit i have mentioned is not much use other than for pumping tyres, spraying and as an air blast gun
maybe?
To be honest that is probably not far off what i would need it for. If it would run a DA etc then great, but it is not worth an extra £300+ to me
personally, for all the oftenness i would use it.
Thanks for the tips all the same.
I am still the winning bidder so far, but there is still 13 hours or so to go, and i'll be quite happy at the price its at currently (approx
£87, compared to Screwfix £140). The price will probably inflate ( ) dramatically in the last hour or so.
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britishtrident
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| posted on 5/4/05 at 07:07 AM |
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Sanders, sand blast guns, air saws and grinders all need a VERY BIG compressor -- really beyond anything you find for domestic single phase.
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NS Dev
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| posted on 5/4/05 at 07:16 AM |
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Yes, my sandblaster (homemade pressure pot type with 3mm carbide nozzle) makes my 14cfm compressor (3hp, max I can run on single phase single motor)
run continuously and it cannot quite keep up.
Everything else is fine, but my sander is electric, and so is my die grinder (I much prefer electric die grinders for head porting, much quieter and
much warmer!!!!)
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RogerM
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| posted on 9/4/05 at 05:21 PM |
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Machine Mart will have VAT free evenings coming up warly next month.
You could get a 16SE or 15SE compressor (3HP, 150 L ... just slightly different pumps / arrangements) for about £300.
Can't get better for that sort of money and you will soon wish you had bought more than 2hp / 50l ... I had one for a while then just had to
upgrade!!
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Triton
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| posted on 12/4/05 at 09:14 PM |
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Plumb another receiver(tank) into the system so you increase storage, it will take an age to pump up to start with but gives pump an easier life.
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David Jenkins
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| posted on 13/4/05 at 07:31 AM |
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quote:
Originally posted by RogerM
Machine Mart will have VAT free evenings coming up warly next month.
You could get a 16SE or 15SE compressor (3HP, 150 L ... just slightly different pumps / arrangements) for about £300.
Just remember that at 3HP you will at or v. near the limits for a 13A socket. Mind you, it's what I've got, but you'll find that you
can't use an ordinary extension lead to drive it. The lead will overheat, and also the volts drop across it will make it hard for the compressor
to start (max load and current at start-up). I made a special extension lead using really heavy-duty cable, and leave it lying unwound on the
floor.
Oh - and look for that very useful compressor feature called "soft start" (name varies according to make). This is a valve on the
compressor cylinder that is open on start-up, allowing the motor to run up to speed before the load is applied. After a few seconds the valve is
closed. This means that the start-up current is much reduced.
cheers,
David
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clbarclay
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| posted on 13/4/05 at 07:44 AM |
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If 3hp proves too much for 13A 3pin, then get a sparky to wire in a 15A or even 30A 3pin plug (240v single phase) into the garage.
[Edited on 13/4/05 by clbarclay]
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