Air Compressors

[Tintin]

I am thinking of buying an air compressor for domestic/DIY use - in the first instance to run a spray gun to wax inject body panel cavities, and then to expand into other air tool use. I am thinking along the lines of:- electric motor powered; oiled; 50 litre capacity 6-18 cfm; 8 bar. Does anyone have any particular recommendations by manufacturer or model please (and any "don't buys").

Thanks.

Robbie

[poprivet]

I've always used https://www.machinemart.co.uk/ for my air equipment, they have many models and all the fittings etc.

I would personally avoid Halfords and any 'bargain' ones supplied by Lidl or B&Q etc

[oldtimer]

Hi Robbie,
I agree with Pop and would use Machine Mart as a supplier. There are many models in the range some of the small ones lack both cfm and capacity I suppose more suitable for model makers.

There are an enormous range of air driven tools available and their air consumption vary considerably therefore I would consider the choice of cfm to be the priority. You mention 8 bar pressure - I think that is 8x 14.7 = 120 lbs. / sq. in in real money. In my experience most tools require about 80/ 100 psi even when using a shop air supply.

I know my impact wrench (windy gun) and air hacksaw use large quantities of air as do car spray guns. My compressor lacks capacity sometimes but it only takes a few moments to build pressure again. This would not do if spraying a whole car.

So a study of required cfm of various attachments may give you a clue as to what would suit your needs, Sorry but cannot remember either cfm or capacity of mine but certainly couldn't do without it.

Might I suggest that you also buy a water separator whilst you are in the spending mood else it will get put off for ever !

I have gas welding hoses as air hoses on garden water hose reels for convenience.

Hope that helps a little

PS And a PLC tyre inflator for starters

[J44EAG]

10cfm is too small to run air tools, ie a die grinder. My 10 cfm unit reguarly runs out of puff. My previous 14cfm unit was much more useful and could run a decent sized spray gun with only the ocassional shortness of breath.

Machine Mart....Mnnn. I`m in dispute with them. I obtained a 18v rechargable cordless driver advertised on their site as having 2x4ah batteries. The sales girl confirmed this so I purchased the unit as it was good value. The unit arrived and it had 2x1.5ah batteries. I phoned MM and complained. That was nearly three weeks ago. Eventually after eight phone calls, MM agreed to send me 2x4ah batteries but in the meantime said to use the smaller ni-cads to get me by. Great I thought. So I pushed the drill into service as my old DeWalt had given up the fight. I then had another phone call. Sorry no 4ah units available. My reaction was to say that the listing said 2x4ah and it was confirmed by the sales unit. So I ordered on that basis. During this saga, the original listing still appeared as 2x4ah batteries which is clear mis-description. Only last night did MM take the listing down. MM refuse to take my unit back as it has been used. The MM sales girl was quaking in her boots when she phoned me to say that 4ah units could not be sourced. I sited mis-description and poor advice. MM Marketing then said they need not take further action due to their "errors and omissions policy". I`m chatting to my legal friend tomorrow.

So MM mis-describe on their listings, provide poor after sales support, don`t fully understand trading terms and wriggle out of liabilities giving no thought of the negative effects causing a once loyal customer to burst into print about his story on the internet. An email will be sent to MM after my meeting with my friend and might perhaps contain a link to this post. If MM wish to sue me as a result of these words, then let them try. I don`t care.

So there we go. MM are a rubbish company to buy from. Happy to take your money but not act in an acceptable manner when challenged. Don`t expect any help from them when things go pear shaped. I think I should write a product review on their web site...

Mike K

[ptjs1]

Hi Robbie,

Apols if you know all this, butmake sure you understand the difference between CFM Displacement and CFM FAD. If a supplier only describes their compressor as XX CFM, it will almost definitely be Displacement. You really need to know the FAD (Free Air Delivery) figure.

There is no substitute for large power and large tank. Go for the biggest machine and tank that you can afford. A nice choice would be a 3hp 50litre, oiled Belt-drive model, but they are more expensive. A Direct-drive model will be ok and cheaper but noisier and not as efficient. Anything smaller and you will struggle on certain tools and duration of use. You really want a minimum of 9.5CFM FAD, which will be about 14-16CFM Displacement.

I've had very good experience with my last 2 compressors both being SIP models. They do some nice 3hp 50 litre models, both Direct or Belt drive.

As you've probably seen, there are huge variances in the retail prices of compressors with up to 100% variance in price for the same model! you really have to look around carefully, once you've decided which model to go for.

Let us all know once you've decided. And then we'll start giving you suggestions about fittings, maintenance, water-filters, oilers, couplings etc etc !! The world of air-tools is addictive!

Good luck

Paul

[davidr]

I have a SIP compressor that has been fairly reliable. It only failed when I neglected it and it didn't have enough oil in the sump and seized. The parts were readily available (although rather pricey) and its up and running again.
I can't remember the specifics but its a twin cylinder direct drive with a large tank (100 ltr I think). When I'm home again later in the week I'll look up spec.
I'd agree with Paul - go for a higher cfm and tank capacity and then it will cope with ease - better that than getting a cheaper one that doesn't deliver the power that's a false economy. Price difference is probably about £100 for the higher spec?

[Tintin]

Thanks for all the replies and advice.

I too have had a poor experience with MM recently - not with their after sales service but with poor quality and breakdown of machinery (a scroll saw - they sent a replacement but that was also defective), so I'm wary of them now.

I would love to spend £400 - £500 on a belt drive compressor, but I don't think I would use it enough to justify that range of cost - and then there are the tools to buy in addition. So, I have done some research and attach a table showing models and features etc. I am inclined to go for one of the two highlighted machines (SC100V or TN3/50-D) and am leaning towards the TN3 (from SIP). Why? Because these two tick the essential performance boxes of Pressure, Tank size, Air flow rate, and Motor power and are a reasonable cost.

Nevertheless, I will sleep on it and see if I still feel the same tomorrow!

Robbie

[ptjs1]

Hi Robbie,

If you're limited to about £250, I'd buy the SIP TN3 of the ones you've listed. Good price at £204. Cheapest I could see it was £212 delivered.

I THINK that all those figures are Displacement. You really have to get the CFM FAD figure for each model to know what you're buying and how well it will run your tools. There isn't a straight correlation. Poor efficiency models can have a high Displacement figure that does not translate well to a FAD figure. All the booklets or technical spec will state the FAD figures.

Cheers

Paul

[oldtimer]

Hi Robbie,
You seem to have had a pretty good response to your enquiry - so it's down to you now - do let us know what you end up with

[Tintin]

I THINK that all those figures are Displacement. You really have to get the CFM FAD figure for each model to know what you're buying and how well it will run your tools

Yes, all my figures are displacement but FAD figures are not always published on line or in the product handbooks. I gave up trying to find the FAD figures for Air Supplies and M Mart but called the technical department of SGS for theirs. The SGS SC100V has a FAD of 10.6 CFM and the SIP TN3 10% less at 9.5 CFM. The displacement figures are 14.6 and 14.7 respectively. I reckon either will be OK for my needs, but you are right to make the point Paul and thanks for the guidance - much appreciated.

Robbie

[Jhdee]

I have the SGS SC100V and I'm very pleased with it.