First thing about spraying, is guns require various volumes of air dependant on there types. http://www.spraygunsdirect.co.uk/product_info.php?cPath=47_79&products_id=4974 standard kestrel spray gun claimed requirement is 7 -12 cfm or a 2-4 hp compressor. http://www.spraygunsdirect.co.uk/product_info.php?cPath=47_79&products_id=5055 sata reduced pressure gun, requirement 10cfm or a 3hp compressor http://www.spraygunsdirect.co.uk/product_info.php?cPath=47_79&products_id=5970 hvlp satajet requirement 15cfm possibly a 5hp compressor
Now its not all bad news a cfm or cubic foot a minute is actually about 30 ltrs a minute, so this is where tank size comes into play. (I assume you are thinking of spraying a car) its a 50 ltr tank which means if you draw 10cfm thats about 300ltrs a minute, you have a reserve supply in the tank but as it is a 2hp compressor its FAD (free air delivery) will be around 6.5cfm. the tank will help make up the short fall in required cfm, but you wont have long. If you can get yourself into the practice of spraying a panel at a time, then waiting for the compressor to catch up you will most likely get away with it.
And don't confused CFM Displacement with CFM free air delivery.
The CFM FAD is the figure used to quote a tool's consumption, IE the figures irondarren has given you will be the CFM in FAD.
IT is the Free Air Delivery figure that your compressor gives that is important. Its the machine's true output if you like.
Manufacturers of cheap compressors try and fool you into thinking their machines supply more air then they do by quoting the machine's displacement. In most cases this is a totally irrelavent figure as you want to know what the machine will give you, NOT what the pump draws in.
If the manufacturer has something to hide they don't quote the FAD, or bury it in a load of small print.
Looking at similiar machines expect a peak FAD of 5.6 CFM, the continuous figure is more like 4, these are reasonable machines, who knows how good the pump on the netto is.
bigbeefy, how about 2 of them . to be honest you wont get anything for £100. I know someone that just bought a clarke one off ebay 3hp, 160ltr tank and that was over £250 second hand.
Two of these units if connected together will supply enough air. If you careful how you spray, try to break the spray job into parts, so you can pause between panels where possible it will work. It wont be a perfect spray job. If your using 2k paint use a slower hardner, this will allow you to restart without dry spots. It can be done if it must be done, and if you budget will only go to £100 then thats about all you will get.
I bought a 3 HP SIP on a 50 litre reciever, one with seperate pump and motor, belt driven. I'm thinking of remounting on a 200 litre one as its as much use as chocolate tits on a plastic fire guard for running anything with such a small reciever.
As irondarren say`s cut the job down them are big vans so need a lot of air, I use an old set up of these http://www.spraygunsdirect.co.uk/product_info.php?cPath=47_80&products_id=5933
to do the vans but have a big enough compressor to cope, the trouble with those cheap compressors is they can only run for about 15Min's then they need a 15Min rest, as has been previously said get two plus some extra tanks if possible and do the roof first, mask off then do one side etc, thats the only way I can see that you`l be able to do it
Hi guys, I'm in a really similar situation to bigbeefy, where budget is small but hopes are high! I have to say I'm really taken by the idea of getting two of these cheapo compressors and linking them together. I've seen the earlier "Sunday afternoon" post where a Clarke and an Airmaster have been joined directly from the tanks using copper pipe and compression fittings with what look like good results, to the point of jumping in the car tomorrow to the nearest Netto! Should the built in regulators in both comressors be avoided in place of a single stand alone regulator/filter as in the earlier post? Bit unsure of how to approach this, so would rather ask and look stupid than make a big bang and have bits of metal flying round the garage Any advice would be greatly appreciated.
I wouldn't join the tanks using copper pipe. Best to use some flexible hose. Waste of time using the regulator off one of the tanks too as this is probably restricting the output of one compressor let alone two.
Your going to have to shell out for a decent sized filter regulator, even if only a cheapy off ebay.
You'll have to tweak the pressure switches slightly on each tank so both compressors don't fire up at the same time. Don't think your electrical circuit would take it.
Should still work out a bargain though. The twin motor SIP ones are over a grand.
Brilliant, thanks for your reply. If I could just idiot proof myself a bit more.....
If I connect flexible airline straight into the tank of both compressors feed these into a Y connector, then feed the single line into a filter regulator, then line from this to the air tool. Does that sound about right?
Would one of these do the trick?http://www.machinemart.co.uk/shop/p...r-lubricator/path/air-line-equipment-air-hose
Would this regulator then control output pressure to the tool and the pressure switches on both compressors detewrmine when they both kick in and out?
That'll do fine for the regulator and filter. You don't need the lubricator for spraying, only for air tools.
It won't control the switching on and off of the compressors. The compressors will already come with built in pressure switches to control the cut-in cut-out, you will just have to adjust one of them slightly. Should be as easy as removing a cover and adjusting a screw or slipping a washer under a spring.
Thanks stormin, I really appreciate the help. All this considered, Netto have got themselves a deal! Just hope they've got two left!!
Will let you know how I get on, I feel some tinkering coming on this afternoon and tomorrow!
Cheers
Ian
Actually, that's a really good point and I'm pleased someone asked it before I just went ahead and bought the filter/regulator/lubricator. Is there a better item to get if like me you want to alternate between air tools and spraying, or is it just a case of draining the oil out of the reservoir before spraying.
On the original note, bought the cheapo compressors today, have to say I'm pleasantly surprised! Don't get me wrong these things will not compete with units costing 3 times as much but I have to say at first glance they look pretty well made. I did get a few strange looks in Netto, both me and the missus pushing trolleys with just compressors in them Just your normal weekend visit to the supermarket!!
Just need to pick a few connectors up and a regulator of some sort and I'm going to connect them up tomorrow.