Compressor for the garage / amateur mechanic / paint spraying

UsernameAlreadyExists

I am an amateur mechanic with aspirations to improve my "home workshop" facilities. I've decided that I think I need an air compressor because I'd like to dabble with paint spraying. I've always fancied an airline with the drill thing that manages to get wheels nuts off in about a second and I'd also like to be able to inflate tyres somewhat quicker that the cigarette light powered compressors that seem to take ages! Ultimately I think I'd like a tyre removal and refitting tool with a view to being able to have a go a refurbishing alloys.


In short, I have come to the realisation that I can look at numbers & stats against the various compressors available on ebay etc all day, but they mean absolutely nothing to me.


What do I need that won't make me regret spending too much or little for the applications I've mentioned? Are there any notable brands that are good, and any to avoid (and why?). I am thinking I need 50litres with 9.6cfm ... but I've no idea why. So I'd appreciate any input available, thanks

nobulljusttruth

Here goes:

CFM (Cubic Feet per minute) is the issue. Forget the pressure thang,(PSI) as that makes little difference. The compressor motor if electric can only go to 3 HP (Horse power) for a domestic 240 volt supply.

When the motor starts is draws 30-60 amps from the supply, (this all makes sense later). Once running it draws about 16 amps.

Tank size
size of pipes
max PSI
CFM. is the king.

The pump starts up and fills the tank, then the pump stops, your spray gun takes 13-15 CFM to spray a car panel unless you have a specialist gun. So once you have used some air it starts up again.
If your pump is not putting 13-16 CFM into the tank, it will run for and try and keep up. I would only suggest that you get the biggest tank and highest CFM you can afford.

150 ltr tank and 15 cfm will do most jobs, and your wheel nut machine, maybe a small sander and all small tools like air drill, tyres, etc.

I have a road compressor that give out 65 CFM but still only 140 psi. so PLEASE forget PSI, a typical exapmple is those cheap power washers.

2000 psi.... wow, but how much water 7 lires per minute.
a pro washer also give out 2000 psi but 15-20 lyrs per minute so it washes better,


Pro size spray gun 12-15 CFM
Nut runner 25CFM min
Sander20+ CFM
air drill 5-7 cfm


\hope this helps.

PS hose internal diameter also holds air so bigger the better,

UsernameAlreadyExists

Wow, thanks for that. What you've said makes perfect sense, and I am going to have to rethink my budget somewhat. I am not surprised but it's always going to be the same story - you get what you pay for.


I do wonder what the purpose of the "little" ones are though? I thought that 50L and 9.5cfm was a small step up from what seemed entry level so I thought I was being relatively safe, but apparently not!


I've seen some road compressors, and they seem a little hard to accommodate and a little bit overkill . These are what power pneumatic drills for digging up roads?

skivenov

If the biggest thing you're spraying is wheels, you can probably get away with a smaller spray gun on a snake compressor. However, you're spraying panels, you will find is shortcomings.

trailingspouse

You're not my husband are you??

I know nothing about compressors apart from being stuck with one when my removal team didn't put it on the van (thinking it was an air bottle - idiots), and I was lumbered with getting it into the boot of the car and getting it out again at the other end.

HOWEVER - I do know he got it off ebay - might be worth a look once you've decided exactly what you want. Cost him £50.

londonTiger

im looking for one for my air riveting gun. Gumtree has a lot of entry level compressors for sale as people upgrade to bigger units.

Niv

It may also be worth taking a look at ToolStation, I know they sell that sort of thing, not sure if its too light weight for you though!

Niv

potbelly

trailingspouse wrote: »

You're not my husband are you??

HOWEVER - I do know he got it off ebay - might be worth a look once you've decided exactly what you want. Cost him £50.

One bit of advice, if you are buying second hand. Ask the seller how often they vent the air tank. All too often users run their compressor but never vent the tank. This leaves condensed moisture in the tank and it will rust through from the interior. Unfortunately it is almost impossible to inspect the inside of a tank ( complete dismantle of pipework and viewing through inlet/outlet holes), so the best you can do is ask the owner. If you get a confused response, suggesting they are unaware of this potential problem, I wouldn't touch it!

Apart from that, as has already been said, go for the biggest volume supply rate (cubic feet/min. or litres/min.) at the highest pressure you will need. 100PSI will deal with most tools and is available from most compressors, small to large.
Hope that helps, and good luck with the business

vaio

We've used a couple of the little Wolf ones in an industrial setting with no issues (so far)

http://www.ukhs.tv/Workshop/Air-Compressors

Some of the pricing is bizarre (compressor alone is £x, compressor plus accessories is cheaper) and they also sell on ebay.

As others have said, bigger is better in terms of tank size, pressure (go for 10 bar/150psi rather than 6/115) and FAD

Gloomendoom

If you need to run it off a 13A plug, you will need to keep an eye on the power. 3hp is probably as big as you will want to go.

vaio

yep, and if you need lots of air but only have a single phase supply you can get ones with two single phase motor/pumps fitted but the cost is £££££

https://www.cromwell.co.uk/SIP8800525B