Power tools - air compressor

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mdf

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#28615 5-Dec-2008 21:12

I have burnt out my angle grinder (too much sanding dust in the cooling ducts I think) and am looking at replacements. I also did a drill a couple of years back, and so am thinking about shifting to an air compressor system. It would primarily be for drilling/grinding/buffing etc., but certainly having spray painting and air duster options would probably be helpful too. It is very much just for moderate DIY / home use, nothing industrial.

I have tried to look into the options a bit, but haven't been able to find a whole lot of unbiased info. So...

The obvious disadvantages are paying for the compressor, then the tools as well, and lugging around a heavy noisy compressor. On the flip side, the tools themselves are cheaper and lighter, and (as I understand it) not possible to burn out. But is there anything else that tends to point one way or the other? What are others' experiences?

I am not sure however about the different compressor options - I think there are screw and belt driven options? Is one better than the other? Anything else along these lines?

I've just been looking in assorted hardware and car catalogues, and there seem to be any number of el cheapo options. Is this one of those things where you get what you pay for, or are the expensive one just expensive because of the name on the side?

In terms of the couplings between compressor and tool, this seems to be standard? I have not seen any references to coupling types?

As I understand it, you also cannot use most of these to do anything like recharge scuba gear or an air tank for a beer keg, since there are minute amounts of lubricating oil that tend to come through? Not sure if this is true or not, but I would not be using it for these purposes anyway (though the beer keg isn't a bad idea).

Or would it be better to stick to power tools? The catalyst for looking at this was replacement anyway, but two tools in several years of moderate use is probably not too bad really.

Any info most appreciated.

hellonearthisman

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#182413 6-Dec-2008 01:04

If your going to Air to replace an angle grinder then you need a compressor that can deliver 20cfm of air. Sanding, you can use a 16cfm compressor, belt driven. The rotary screw compressor are great, 150cfm but a cheap one is $5000+ and that much air will blow the guts out of your machine. A cheap option is to use two 16cfm compressors, that will give you enough air if you want a grinder or a sand blaster. Still that's $2000+ but it still doesn't provide the reliable toque of power tools. There are direct drive compressors, they are like disposable and cheap.

I use angle grinders for stone sculpting, I have a 9" grinder, fitted with a 7" grinding disk. That works great as the 9" grinder runs slower, has more torque and you can fit 115mm(4.5") or bigger disks to the 9"

When buying a grinder, keep an eye on the watts for the tool. I like these A B that are on Trademe, great value.
These tools may not last for ever, but they will provide very good bang for your $

The air for other stuff would be ok, but your would have to use some propper water separators and propper air filters (25 microns ?),
With the air cleaned, with could even be used for some crazy cpu cooling.

Great question :)

marmel

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#182435 6-Dec-2008 08:10

The reason you can't fill dive tanks etc is because most compressors won't produce enough pressure. A dive tank can be filled to about 3000psi, most cheaper home compressors won't go over 200psi.

200psi is more than enough though for 99% of the jobs you do around the home.

n00dy

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#182464 6-Dec-2008 12:17

I agree with hellonearthisman, compressor size is the most important factor, i have a small A/c unit (single piston 2 stage) and I have had it for about 5 years, it is under powered and undersized however for those times I need it it is OK, when spaypainting the motor runs almost all the time to keep up, great for the air ratchet as that is a stop and start use. When I replace my unit I will go to a higher spec unit. One thing i did though was to get an old CNG car tank, bolt it to the wall and daisy chain it in, takes a while to build up a little pressure ( my compressor maxes at 110psi ) but this allows me a bit more volume.

mdf

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#183120 9-Dec-2008 20:17

Cheers guys.

Apologies if this is restating the obvious, but just to check I understand:

Screw is better than belt driven (and correspondingly priced)

Belt driven is better than direct drive (direct drive being the cheap ones advertised by the likes of Repco and Supercheap all the time)?

And the air throughput is important because you need to keep the pressure up? i.e. if you use more air than you take out of the cylinder you are going to lose power?

Maybe I will stick with power tools. I understand those (more or less...)

Thanks again.

paradoxsm

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#183159 9-Dec-2008 21:39

Thanks for the question and replies, I got a lot of good info out of it, air tools have always been a bit of the black domain.

I had a cheap direct drive "SuperWorks $99 dollar deal" compressor with a cheap nibbler and just as a blower works fine but it's was definately "get what you pay for"