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DrKai
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Following a lot of helpful advice on here I pretty much have the garage sorted. Now to fill it. 

Can anyone recommend a compressor?

I'm limited to single phase power. Would like to run all things associated with restoration: sander, wrench spray gun etc. Again no budget but I don't want to go massively over spec for no reason. 

I've done some research and it seems makes power on 230v is aroung 3hp which gives circa 16cfm. Various opinions on whether this is enough for the above. Next step up would be a twin pump 30cfm job but generally £1200 or so. If this is what I need I'll pay it but if I can get away with smaller great. 

All help appreciated. Thanks. Kai

 

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Kai.

It's a big topic.

Although I am not recommending this company, they have produced an interesting fact sheet: https://www.sgs-engineering.com/help-advice/air-compressor-buying-guide-which-compressor-should-i-order/

Basically if you intend using air hungry tools (i.e. sander) then you need will need 3HP with at least 100L / 150L tank and the compressor must have enough free air to run the item. Ideally your unit should be belt drive rather than direct, as the former is quieter, more manageable and produces far less wear & tear.

As for makes it's personal choice - just ensure you choose a unit that has good spares back-up and universal accessory fittings.

Regards.

Richard.

 

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I have a SIP 3hp compressor with 50L tank. 

Most compressors that sort of size WILL struggle with a DA sander, but saying that the CP sander I borrowed used rather less air than the SIP version I own.

In terms of spraying, I have painted several cars with it. Use impact wrench, blow gun etc and no problems experienced. By my reckoning if it is just the sander that it struggles with, you are better off buying an electric DA sander. Saying that, I am not a great fan and tend to use an electric orbital sander or indeed grinder for getting the shape correct, and finish by hand (with a block)

I thoroughly recommend a belt drive over a direct drive compressor, much quieter!

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Good choice Karl and the company make / sell decent units.

This size unit will happily run off a domestic 13A ring main, but once you get to bigger tanks it is advisable to run a 16amp line specifically for such units. That of course is fine if your consumer board is conveniently located to where you can run such a line; if not it can be a pain, hence why many compressor owners stay at the 100L tank limit. 

Regards.

Richard.

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That's impressive Colin, that said the majority of modern houses or upgrades now run a 16amp ring so perhaps your 200L may be benefitting from that and not tripping. As you rightly point out, it is the start-up that pulls the most amp - just like an electric fan on cars.

Regards.

Richard.

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2 minutes ago, classiclife said:

modern houses or upgrades now run a 16amp ring

Do they? Last time I looked they were still 32A - radials tend to be 16 or 20A - but I know there are potential issues with rings due largely to lack of testing once installed (I rewired our house before we moved in in 1994 and it was tested then and hasn't been officially tested since) as connections in the back of sockets can become loose due to heating - or even just putting back into the wall if the connection flexes on moving and wasn't quite tight enough - and result in effectively a 32A radial - which with 2.5mm cable is not a good idea!

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Impact guns need a decent air supply , more volume than pressure , save the hassle a battery one is far more useable

And goes anwhere

Ive got a whole stack of guns , cutters , nibblers etc    most new never used and never will be now

If theres any interest drop me a line 

Add with any spraying its good to have an air drier in the line  and for tools an oiler

Pete

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Had mine a while, like this, but I think with a bigger reservoir:  https://www.machinemart.co.uk/p/clarke-raider-15500-3hp-50-litre-air-compress/

It's a 'direct drive' compressor, not belt driven, and I was warned that they are noisier.    THEY CERTAINLY ARE!     Eventually, I enclosed it in a box, with an extractor fan blowing into the box  to keep the enclosure cool, and that allows conversation in the workshop while it's running, although  it's still loud.   The fan has a delay circuit on it, so it keeps on blowing after I turn the compressor off, to deal with residual heat.

Whatever you choose, Kai, I'd plan the siting of the compressor carefully.    If you can put it in a small outhouse at the back of your workshop (away from the house!) I think that's ideal, as long as it's secure, and well ventilated.       When I boxed my compressor, I put it in the furthest corner of mine, and considered a pipe network to deliver air to the other corners, as the originally portable compressor was now a fixture.     But in fact, I bought an air hose reel, mounted that on the wall at a central point and ran fixed hose from there back to the compressor.  With a length of 'curly-whirly' hose on the end for flexibility, this answer all my requrements, in and out of the workshop.

On the point above on current draw, 3HP is a hefty electric motor that will draw about 10A when running, but much more on starting.   This isn't due to cold oil, but to the physics of electric motors that generate a back EMF once running, reducing the current draw.     I first wired mine though a standard, 13A fused socket - and it blew the fuse frequently.   Now It's 'hard-wired' into the ring main that I had been advised was safe for that starting current.

In the past the same circuit had run a spot welder, an exciting bit of kit that I hired for a special job.    It blew no fuses, but did odd things to the TV picture, 'er indoors told me afterwards!

John

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18 hours ago, classiclife said:

That's impressive Colin, that said the majority of modern houses or upgrades now run a 16amp ring so perhaps your 200L may be benefitting from that and not tripping. As you rightly point out, it is the start-up that pulls the most amp - just like an electric fan on cars.

Regards.

Richard.

Ah now there's coincidence! My new garage was fitted with a dedicated 16 amp circuit for the 2-post lift, and it regularly trips the RCD, no matter what is attached, so is next to useless. The 13 amp circuit runs perfectly and all other sockets will run both lift and compressor all day with no worries. The electrician is to come back - or so he keeps saying - to look at it for me.

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If the RCD is tripping you have a fault to earth - or at least the leakage to earth through the motors etc is higher than the limit of the RCD - which in a domestic environment is normally 30mA - you might need to change the post circuit to a 100mA one - or put it on a non RCD circuit if its only the lift on it (Ie. a fixed appliance)

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Thanks for the input guys. Garage is 60m or so from house so don't need to worry about disturbing those inside. It's the neighbors who need be worried. Garage has separate power supply and plan to do a dedicated feed from the box to the compressor so shouldn't be an issue there. I think I have found a good unit (see below) unless anyone would dissuade me? Pete once I'm all set up I'll get on to you about the tools I'm sure. 

https://www.toolstoday.co.uk/sip-airmate-150-protech-150-litre-4-0hp-slow-run-air-compressor-230v-18amp?gclid=Cj0KCQiAhrbTBRCFARIsACY7MW1FiV14kZKkMZi7QXpWgR2rZCLHKBLBi7s0gW--1UKPkEW7tjKQum8aAtIGEALw_wcB

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Hi. I bought the predecessor to this https://www.machinemart.co.uk/p/clarke-tiger-8250-2hp-24-litre-air-compressor/  back in the late 90`s, primarily to run a Nailing Gun when doing a Self Build. The only difference is mine runs to 10bar not 8. The biggest drawback is having to wait occasionally whilst it "catches up". It`s given good service and was boon when I had the "Yank" R-V as none of the garages had Air above 60psi, where these tyres ran at 75 to 80. I`ve Painted with it, run most air tools off it. and it was Cheap, under £100 back then was good. Another benefit was the R-V genny would run it!.

 

Pete

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