Spray painting compressor

[garfield]

Hi,
I'm going to buy myself a new air compressor so I can spray my entire kitchen and was wondering what would size compressor would be best to buy that will give me continuos air while spraying to give me a good job. I'm not a full on spray painter so I'd like to be able to get out of it for under $500 if I can.... the cheaper the better :U as I say I'm not always spraying so I don't need a a top of the range compressor.
Any guidance much appreciated.<O:p</O:p
Thanks
Geoff

[Dengue]

You need a compressor that will deliver about 10cfm at the gun for effective spray painting, and a separate water trap filter and regulator mounted well away from the compressor, giving the air time to cool and the water to condense before it reaches the filter. If the air is hot, as in compressed air, it absorbs the water, and passes straight through the filter.

Hope this helps

[garfield]

Thanks for the reply.
So would I need a belt driven compressor to get those kind of cfm's?

[Dengue]

Probably. And belt driven compressors are much quieter than the direct drive units

[garfield]

Probably. And belt driven compressors are much quieter than the direct drive units

Thanks Dengue.

Which of these 2 do you think would be better please?

Blackridge 2.5HP Belt Drive Air Compressor - Supercheap Auto Australia (http://www.supercheapauto.com.au/online-store/products/Blackridge-2-5HP-Belt-Drive-Air-Compressor.aspx?pid=296172#Cross)
or
C324 | RABD255/50/2.5 Air Compressor | machineryhouse.com.au (http://www.machineryhouse.com.au/C324)

Thanks
Geoff

[Dengue]

Each of these compressors delivers less than 6cfm. :(

I would wait for some other contributors to find out if that would be suitable for spray gun work that you will be doing. I doubt it.

Also, only one has a water filter, and not sure if it will work as it is right on the compressor where the air is hot and holds water which will come out of the air in your spray gun and on to your finish. Hence the need for a remotely connected water trap if you are going to do spraying.

Some people connect a second tank ( with regulator output, but no compressor) to the outlet of the first when spraying, with the moisture collecting in the 2nd tank.

Have you looked at any of the HVLP outfits? Earlex 1900 HVLP or Wagner W450SE unit

[garfield]

How about this one?

NEW UNIMAC Industrial Air Compressor 120L Receiver Petrol Driven Tri-V Piston | eBay (http://www.ebay.com.au/itm/NEW-UNIMAC-Industrial-Air-Compressor-120L-Receiver-Petrol-Driven-Tri-V-Piston-/160921621965?pt=AU_Air_Tools&hash=item2577ad15cd&_uhb=1#ht_3437wt_1397)

I'm confused :? this one has less ltrs per min but has a higher cfm rating

SYDNEY TOOLS - Chicago Air 30L 1.1HP Aluminium Compressor (http://www.sydneytools.com.au/shopexd.asp?id=11908&bc=no)

How does that work??

[chambezio]

WOO. Wait a minute. Lets just stand back here and have a look at a few things.
You want to "Spray My whole kitchen". Walls as well as the cupboards?
*To spray the walls is going to be a head ache due to the clouds of over spray. You will have to isolate the room and have forced ventilation so you can at least see what you are doing.
You want to spray the cupbords
*This is doable with plenty of masking up so you only paint what you are aiming at

Will you keep the compressor for use in your shed after this paint job?

The absolute minimum size compressor is 10 CFM!
This will also drive shed tools. Electric compressor is a lot more convenient than petrol.

Have you done spray painting before? Why do you think a sprayed job will be better than using non powered means.

If you are on a budget, how about hiring the gear? They may even supply the spray gun too.

[garfield]

Thanks for the reply.

yeah sorry, should be more specific. I only want to paint the cupboards and the end panels etc of the carcasses.

I will keep it for my work shop for sure.

Yes I have sprayed before, I wouldn't say I'm an expert but with a bit of guidance and a few more practice runs on some scrap I'm sure I can do an acceptable job.

Could I get away with this one (below link) by an chance?
Colt 10AMP Direct Drive Air Compressor COLT282 - Masters Home Improvement (http://www.masters.com.au/product/100589297/colt-10amp-direct-drive-air-compressor-colt282)

Thanks
Geoff

[crowie]

G'day Geoff,
Rather than going to hardware stores & the likes, how about an industrial supplier.
We used to use Clisby Air Compressors years back & I have had one at home for 20yrs.

AIR COMPRESSORS (http://www.clisbyengineering.com.au/index.php?option=com_content&view=article&id=13&Itemid=16&lang=en)

IMHO - worth another look......Cheers crowie

[Arron]

I think Chambezio is on the money. Hire an big compressor to do a job this big. Buy your own gun. Later, after you've done this job, you'll have a much better idea of what you need so you can buy with certainty.

I have a 2.5 hp belt drive with top specs, but I'd still be hiring something a bit bigger to do a job like this with lots of flats.

[garfield]

Appreciate the replies...

At the moment I have an old GMC 32L 2HP compressor GMC 32L 2HP Dual Tank Air Compressor - Bunnings Warehouse (http://www.bunnings.co.nz/products_product_gmc-32l-2hp-dual-tank-air-compressor_444.aspx) that I have sprayed with in the past and haven't had too terrible a result, don't get me wrong there was no massive jobs done but it was still a piece I wanted to get a good finish on though, and that machine is nowhere near 9CFM's.

I really would like to buy one rather than hire as I will use it from time to time on my other projects at home, so is there any chance at all I could get away with the above? I take everything on board that I'm being advised because I have no idea - but if there is a good chance I can get the job done with the unit from Masters that would be great.
Thanks heaps
Geoff

[crowie]

G'day Geoff, From memory, you get 4cfm per 1hp...... Hope that helps in compressor selection, cheers, crowie

[Arron]

Geoff, I understand what you're trying to do and how difficult it is to size compressors when you dont have the opportunity to try them. I spent ages searching for a compressor, making charts of makes and models and cfms and hps etc etc. Eventually I bought a 2.5hp belt drive which claims 13cfm because it was the most powerful, smoothest nicest machine I could find that would work within my limit of 10amps. I think I paid about $550 for it new so it's lightyears in front of the ones you've posted for roughly the same money. Now I find its OK for doing small stuff, and I did 7 dining chairs last week (see post below) which is my biggest job with it so far, but if I was doing big furniture or kitchens I think I would struggle with it. It has a 50 litre tank and once the tank is full and the motor cuts out I get only a few seconds spraying (I'd estimate about 12 secs, enough to do about 1 foot square) before it gets down to 6 bar and the motor cuts in and starts pumping again. Dont get me wrong, it never stops pumping out air, and pumping it out hard, but the problem is when its around that 6 bar the characteristics of the spray are significantly different to when its fully charged at around 9 bar. When I think of the amount of effort I go to to make sure that everything (like viscosity, fluid adjustment, spray pattern etc) is right for spraying then its logically impossible that it can perform identically at both 6 and 9 bar. Does this matter ? Well it depends on how fussy you are (or more likely, your wife is). I've lately become aware that it doesnt matter as much to me as I thought it would because I'm aiming for the perfect finish so usually do pullover, respray, then buff with at least 2 grades of cutting/buffing compound, so I tend to turn rough into smooth no matter what. Still, my first aim is always the best possible job straight off the gun as a matter of economy.

Now its likely that tomorrow I will be using it to spray some lacquer (sealer and top coat, 1.7 and 1.4 setups, hvlp and lvlp respectively) so if it eventuates I'll take some metrics for you. I'll look at how long I can spray before the motor cuts in and how much I can do at top quality before the iffy stuff starts.

Its hard for people to advise when everyone has a different standard of whats a good job. When I was new at it and using my direct drive 2 hp machine I was perfectly happy with the results (for about a month). I did a whole bedroom suite with that setup - hideous, but I was happy with it at the time and my wife still is. I also did an outdoor setting with it - but I'm still happy with that because its outdoors so I"m not really aiming for a piano finish outdoors anyway - which I mention because it introduces another factor, different contexts support different standards of finish.

Finally, the reason why I suggested hiring is because I"m assuming that jobs like doing a kitchen wont come along often for you. Kitchen cupboards have a lot of flat surfaces - which are demanding because you dont want a cutout or the spraying characteristics to change while you are doing a big flat surface. So I figured you could buy a medium power compressor like mine for ongoing use doing furniture and so forth, but hire a big one when a job like the kitchen comes along. That way you dont need to fork out for some overpowered beastie which you may never again use to its fullest. Also, anything over 2.5 hp is going to require 15 amp circuit, so unless thats available to you I figured a petrol driven hire job is more versatile.

cheers
Arron

[garfield]

Arron, Thanks for the reply mate and the amount of time you took to write it, I really appreciate it.

I called VGA paints at Girraween today and had a chat with one of the guys there as I was interested in buying the below, but explained to him my concerns with the litres per min it was capable of as people on this forum have suggested I need the larger unit that can pump out a minimum of 10 cfm's. The guy told me this compressor would be fine for painting with a gravity spray gun as the painters there work on psi and that this machine was capable of punching out (can't remember how high he said) which would be good enough seeing that I would only have the regulator at the gun set at about 30 psi for painting the enamel paint.

Is he just putting the sales push on me - or is he sort of correct? I rang Masters Hardware to enquirer about a 2.5HP 50L tank model that have which states 162L/min of pressurised air delivery and he told me that the unit would be more than sufficeint for spraying also.... it's really doing my head in!

http://www.vgautopaints.com.au/ross2.75.gif

[Arron]

Yes, it does your head in for sure. Been there, done that.

I find posting questions on a finishing forum is frustrating because most people only know one or two systems well so cant talk comparatively. They find one that works and stick to it, not surprising considering how long it takes to get a working system. I only really know about spraying nitrocellulose lacquer, and various kinds of rub/brush finishes. I havent done much spraying with enamel. I avoid enamel and use lacquer because I dont have a spray booth, so I have to spray outside, and with the longer drying time of enamel every bit of dust and kamakaze bug would end up stuck in there. Lacquer dries almost immediately so any dust or bug just bounce off, very rarely a problem.

I also chose a belt drive because of my understanding that direct drives are noisier (true), shorter lifespan (probably true) and less efficient (true, though the specs should be published). OK to have direct drive for a little 2hp cheapie, but I dont get a $500 direct drive at all.

As for the guys in shops, I generally ignore them unless they are able to answer my question about how many years professional spray painting they have had. Was he talking about stain on a fence, acrylic on a house, or a piano finish on a treasured furniture piece ? And then if you drop into your local panelbeater they will have plenty of experience but typically can only think in terms of humungous systems because they have the economy of scale to set them up.

I found something useful to do was to watch the youtube videos on spray painting. Typically they are about spraying cars - which I think are intrinsically close to kitchens in terms of the amount of flats. Just look at the amount of air/fluid coming out of their guns. You can learn something from watching - and thats that those guys need a lot of air - enough to get good results and then a lot more for just in case.

Incidently, when I spray lacquer thru my lvlp gun I set the reg at 9psi, so I dont know that you can say 'only' about 30 psi. I spray thick sealers thru hvlp at 30 psi. That Ross machine seems to be rated at 7.2 cfm (assuming conversion factor of 0.03532 and measured at same temp and ambient pressure - which they never are so makes conversion another headache) so I think it backs up my view that direct drive machines dont shift much air.

cheers
Arron

[garfield]

Thanks once again Arron. I've revised my budget a little how about this unit mate?

Colt 10AMP Belt Drive Air Compressor COLT312 - Masters Home Improvement (http://www.masters.com.au/product/100589318/colt-10amp-belt-drive-air-compressor-colt312)

[Dengue]

You need to realise that the cfm they quote is at the compressor pump. Normally allow 75% of this at the outlet of the regulator / filter. Imagine what it will be at the end of a tiny diameter hose!

You keep falling over the 10 cfm ( and that is a minimum for good spraying). I'm afraid these little units will not do what you want, which is continuous spraying without waiting for the pump to kick in every few seconds. Remember that the compressor pumps have a duty cycle too, and if running continuously, they will quickly burn out.

Sorry, the posting above about the Clisby was right - you need to look at getting a decent one for the work you want to do.

And these are going to cost more than $500 !!!

Suggest you look at the HVLP units ( Earlex and Wagner I recommended above)

[Arron]

Yep, avoid the hardware stores. I bought mine from Gosford Power Tools. You could ring and ask for a 'Extreme 13 alloy compressor 50 litre 215lpm'. I paid $550 all up last July, but you could probably squeeze a bit more out of them. I stress though, its a nice machine but still not up to doing a car or a kitchen.

I just looked at a couple of cheapo hvlp conversion guns I have here. The 1.4 setup is spec'd to require 6-10cfm at 43 psi and the little touch up gun (0.8mm setup) requires 3-6cfm at 30 psi. Dont forget this is at the gun though, from the compressor it has to go through two filters/water traps, a reg and 10 mtrs of hose.

I understood that the duty cycle on those direct drive compressors is only about 25%.

Hope all this information helps.

cheers
Arron

[Arron]

Stop press. Ignore what I said about my compressor. I've been doing some maths and now strongly suspect that its nothing like 13 cfm. I guess that puts in doubt everything i said about required output too. Please listen to the others, but ignore my posts and my recommendation for the Extreme compressor..
Sorry to have wasted your time.
Arron

[garfield]

Appreciate the replies and guidance everyone.

Arron, not a waste of time mate - you sound to me like you know what you're talking about.

I love this forum and it has always pointed me in the right direction, the only thing I hate is whenever you ask about a product on here it always turns out that it has to be the most expensive :C

[Dengue]

This compressor (http://www.ebay.com.au/itm/AIR-COMPRESSOR-16-CFM-BELT-DRIVE-3HP-50L-3-CYLINDER-CAST-IRON-PUMP-COMPRESSOR-/400347149203?pt=AU_Air_Tools&hash=item5d368cb393&_uhb=1#ht_2307wt_758) is more along the lines of what you need, at a minimum, though I am not sure about how it would go for continuous spraying over large surface areas. You don't want to have to stop mid run and wait a minute or so until the compressor catches up..

Note the comment on the need for a separate water filter / trap, confirms my original comments.

[q9]

This is what I got:

Boss Compressors - BOSS 15cfm 3.2hp Air Compressor (http://bosscompressors.com.au/Air-Compressors/240-Volt-Air-Compressors-/BOSS-15cfm-3.2hp-Air-Compressor)

Sprayed a table with it, and it was big enough not to be running flat out with comfortable gaps between runs. Tank size helps. Bought under the advice of a panel beater friend...15A though.

[Dengue]

Excellent choice q9, this would be the one I would buy to meet garfield's requirements; meets the air delivery spec I proposed ( well almost, 9 cfm v 10 cfm recommended at the outlet, should be OK)

I would be adding a remote water trap, or a simple cooling coil like you see here (http://i738.photobucket.com/albums/xx21/886014/Compressor/file.jpg) to eliminate water totally in the air delivery

[garfield]

Thanks for the replies.
Might follow this guys idea :U

How to connect two compressors in tandem, Dual Compressors - HD - Widescreen - YouTube (http://www.youtube.com/watch?v=FFRYlwnuNZ8)

[Chris Parks]

Most hobbyists either under estimate the CFM needed or refuse to accept the advise when it is given because it costs so much to buy a capable compressor. The other thing they also do is use 3/8" hose instead of 1/2". 3/8 hose will not deliver the air flow needed for spraying and also will hold more water in suspension due to higher air speeds through the hose and the last thing you want is water in the air. If the water levels are too high then the separator may not catch it all and you waste the paint. Two compressors will work but spec them to pump 15CFM.

[Dengue]

I first discovered the problem of water when I blew the dust of a recently sanded workpiece using a small 2hp compressor with 20 litre tank. The whole workpiece was covered in water. I shuddered to think what would happen if I used this unit to spray paint.

Open the drain cock under the tank and look at all the water that comes out.

[q9]

water traps aren't very expensive. I also ran blue HP 20mm pipe around the shed, with about half a metre of pipe below the female t-piece fittings, which I installed a quarter turn valve at the bottom to be able to drain the pipes. Nothing seemed to get past the water trap however, so possibly over kill.

[garfield]

Hey guys,
Well I bought my compressor. I'd like to say thanks to everyone for advice and help throughout this thread I really apreciate it.
On my budget I couldn't afford a huge CFM compressor and was dvised on my budget to buy this one New Ross Ross Air Compressor 240V 36 Litres 2 75hp Portable Diesel Compressor in Northmead, NSW Price: $380 <39053> (http://www.machines4u.com.au/view/advert/Ross-Air-Compressor-240V-36-Litres-2-75hp/39053/) so I did.
I hope it does the job and gets me buy for this project at least.

[Dengue]

Thanks for letting us know, after all the advice and recommendations that have been made on this thread. Glad you got one you are comfortable with, and can afford.

Diesel compressor? Where does diesel come into it, esp as you say it is 240V driven?

[garfield]

I would have loved a more expensive one but just can't come up with the cash for something that won't justify the price down the track... The guy told me that this unit is rated at 13 cfm and was probably the best one for me within my budget.

I must have posted the wrong one because mine isn't diesel.