Spray painting compressor

[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

[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

[Dengue]

This compressor 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

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 to eliminate water totally in the air delivery

[garfield]

Thanks for the replies.
Might follow this guys idea

How to connect two compressors in tandem, Dual Compressors - HD - Widescreen - YouTube

[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> 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?