Spray Gun CFM
#10
  
I have a 20 gal. compressor that has an output of 6.4 cfm. I am contemplating purchasing a spray gun that specs say consumes 7.9 cfm. I assume that is max.
I understand that it is not 100% necessary to have a compressor cfm output exactly match the consumption of a spray gun. If the compressor can't quite keep up, it is easy to pause a bit to let it catch up. Also, one is not usually running the spray gun continuously. For those more experienced, as a practical matter, how close to a match should they be? What difference does 1 or 2 cfm make when stopping and starting frequently as when working on a piece of furniture and especially when your gun settings are less than wide open.
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#11
  Re: Spray Gun CFM by Willyou (I have a 20 gal. com...)
(11-29-2019, 09:50 PM)Willyou Wrote: I have a 20 gal. compressor that has an output of 6.4 cfm. I am contemplating purchasing a spray gun that specs say consumes 7.9 cfm. I assume that is max.
I understand that it is not 100% necessary to have a compressor cfm output exactly match the consumption of a spray gun. If the compressor can't quite keep up, it is easy to pause a bit to let it catch up. Also, one is not usually running the spray gun continuously. For those more experienced, as a practical matter, how close to a match should they be? What difference does 1 or 2 cfm make when stopping and starting frequently as when working on a piece of furniture and especially when your gun settings are less than wide open.

I assume the 6.4 cfm rating of your compressor is at 90 psi, correct?  The 7.9 cfm requirement of the gun is at some lower pressure, for sure, maybe 45 psi.  For most things I spray I use 29 psi at the inlet to the gun, and that includes when I've used the purple HF gun which is rated at higher inlet pressure.  So, your compressor will likely work just fine although it will run non-stop after you empty enough out of the receiver to trigger the pressure valve until you pause long enough for it to catch up.  


I think you will be fine.  However, if you do much spraying your compressor is going to wear out a lot faster than it would just filling tires, etc.  Drain the regulator bowl and tank after each spray session, too, to keep water out of the line.  

John
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#12
  Re: Spray Gun CFM by Willyou (I have a 20 gal. com...)
No. Sorry. I should have said: 6.4 @ 40, 5.3 @ 90. My spraying is infrequent and I mostly do furniture where I'm not continuously on the trigger. Yes. I do drain it after every use and have a water separator and filter on it. Compressor is a California Air 10020c. Nice unit.
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#13
  Re: RE: Spray Gun CFM by Willyou (No. Sorry. I should ...)
(11-30-2019, 04:20 PM)Willyou Wrote: No. Sorry. I should have said: 6.4 @ 40, 5.3 @ 90. My spraying is infrequent and I mostly do furniture where I'm not continuously on the trigger. Yes. I do drain it after every use and have a water separator and filter on it. Compressor is a California Air 10020c. Nice unit.

You will still be fine unless you want to spray non stop at greater than around 40 psi, or the gun requires that kind of pressure to spray well.  That said, it would be better to get a LVLP gun so the required cfm is lower than the rated output of your compressor.  

John
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#14
  Re: RE: Spray Gun CFM by jteneyck ([quote='Willyou' pid...)
(11-30-2019, 08:27 PM)jteneyck Wrote: You will still be fine unless you want to spray non stop at greater than around 40 psi, or the gun requires that kind of pressure to spray well.  That said, it would be better to get a LVLP gun so the required cfm is lower than the rated output of your compressor.  

John

Yeh. I haven't been able to find an LVLP of reasonably good quality with a side mounted cup.
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#15
  Re: RE: Spray Gun CFM by Willyou ([quote='jteneyck' pi...)
(11-30-2019, 10:03 PM)Willyou Wrote: Yeh. I haven't been able to find an LVLP of reasonably good quality with a side mounted cup.

Why a side mounted cup?

John
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#16
  Re: Spray Gun CFM by Willyou (I have a 20 gal. com...)
Generally, they tend to be smaller and, I think, the smaller gun is easier and better to use when spraying furniture items. I just finished a restored glass front book case using a mini-gun with 1.0 mm tip. It worked fine inside and out and I feel like I have better control with the smaller spray pattern. The swiveling side cup lets me spray the underside of the top and straight down on the upper surfaces without spilling.
I would like to get a similar gun that will accommodate larger tips and thicker materials . I have looked at the PPS system but, the whole system just looks too big for my purposes. I have used my $10 HF gun some and it is like driving a race car to the grocery store. The Sprayit 352 is a cheap gun that comes with a 1.4 and a 1.8 tip and has the side cup. Reviews are mixed but, for the price, I can experiment. The next step up appears to be a knock-off Iwata W-101 in the $50 - $70 range from China. I have come close to ordering one but, not yet.
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#17
  Re: RE: Spray Gun CFM by Willyou (Generally, they tend...)
(12-01-2019, 11:23 AM)Willyou Wrote: Generally, they tend to be smaller and, I think, the smaller gun is easier and better to use when spraying furniture items. I just finished a restored glass front book case using a mini-gun with 1.0 mm tip. It worked fine inside and out and I feel like I have better control with the smaller spray pattern. The swiveling side cup lets me spray the underside of the top and straight down on the upper surfaces without spilling.
I would like to get a similar gun that will accommodate larger tips and thicker materials . I have looked at the PPS system but, the whole system just looks too big for my purposes. I have used my $10 HF gun some and it is like driving a race car to the grocery store. The Sprayit 352 is a cheap gun that comes with a 1.4 and a 1.8 tip and has the side cup. Reviews are mixed but, for the price, I can experiment. The next step up appears to be a knock-off Iwata W-101 in the $50 - $70 range from China. I have come close to ordering one but, not yet.

For occasional use nearly any gun will work if the specs. fit your needs.  If you spray regularly though better quality guns generally are easier to use and last longer before the seals give out.  I spray furniture and have minimal problems with a mid sized gun with a bottom mount PPS cup.  The PPS system allows you to spray at any angle and that allows me to get into most places.  If I sprayed gallons of stuff I'd put a pressure pot on the gun I have and that would let me get into even tighter spots.  The side mount guns are fine for detail work, but too small IMO for furniture and cabinets.  

But if you want an Iwata mini gun but don't want to spend more than $70 why not buy an Iwata. $70 Iwata 101

John
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#18
  Re: Spray Gun CFM by Willyou (I have a 20 gal. com...)
Yes. That is one of the guns I've been looking at. The W-101 151g that consumes 5.1 cfm matches the output of my compressor but, I haven't found one yet among the Knock-offs. I saw one on Ebay a week ago but missed it. The 101 152g jumps up to 7.9 cfm. That's what prompted my OP. Maybe it's not enough difference to be concerning. I'm in no hurry. I may just keep watching for another one for a while.
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