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Author Topic: Gravity Feed Spray Guns  (Read 1688 times)

John Leidle

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Gravity Feed Spray Guns
« on: December 18, 2013, 02:03:19 AM »
  For some reason I thought they are relatively new... I was watching a documentary from 1940  & the guy was spraying with one.
  John
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Offline Mark Scarborough

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Re: Gravity Feed Spray Guns
« Reply #1 on: December 18, 2013, 10:52:40 AM »
nope,, they are not,, but what is new is the HVLP, or LVLP technology,, modern machining,, ( last ten years) has allowed the finer control of air patterns and this has forwarded the technology,,
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John Leidle

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Re: Gravity Feed Spray Guns
« Reply #2 on: December 18, 2013, 01:16:12 PM »
 Mark, why had we not seen them often before? 
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Offline Mark Scarborough

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Re: Gravity Feed Spray Guns
« Reply #3 on: December 18, 2013, 04:50:51 PM »
not sure I have a definative answer on that,, I always used a cup feed suction gun,, until HVLP came along, I know that the cup gun always felt more balanced to me,, but with the advent of HVLP it almost required a gravity feed setup because there was not enough vacuum to draw the fluid up the tube in an HVLP setup. My buddy had an Iwata (?)  cup HVLP, it had a whole bunch of extra bits and pressurized the cup to get consistant feed, I hated that gun,, It may also have had to do with the type of material being sprayed,, I know woodworkers used gravity feed , and they sprayed lacquer and shellac,, when you are painting a car, and need to add fluid to the cup,, a gravity feed can be a pain,,
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Offline billbyles

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Re: Gravity Feed Spray Guns
« Reply #4 on: December 18, 2013, 06:30:30 PM »
Quote from: Mark Scarborough on December 18, 2013, 04:50:51 PM
not sure I have a definative answer on that,, I always used a cup feed suction gun,, until HVLP came along, I know that the cup gun always felt more balanced to me,, but with the advent of HVLP it almost required a gravity feed setup because there was not enough vacuum to draw the fluid up the tube in an HVLP setup. My buddy had an Iwata (?)  cup HVLP, it had a whole bunch of extra bits and pressurized the cup to get consistant feed, I hated that gun,, It may also have had to do with the type of material being sprayed,, I know woodworkers used gravity feed , and they sprayed lacquer and shellac,, when you are painting a car, and need to add fluid to the cup,, a gravity feed can be a pain,,

Hi Mark,

I tried an Iwata cup HVLP gun for awhile, I gave it away after about a month of trying to get it to spray the venerable old Du Pont "Imron" which is a pretty easy paint to spray.  I went back to my old favorite DeVilbiss JGA-502 cup gun with which good results were easy to get using most paints from lacquers to polyurethanes.  Finally had to change to HVLP due to EPA/South Coast AQMD so I got my first Sata Jet gravity feed HVLP guns.  The Satas are a great gun - very high quality and easy to maintain; they spray a quality finish at least equal to the JGA-502 cup gun using less material.  I always use a stand made for the gravity feed guns for re-filling the cup.  However, even using a stand for the gravity gun it is still not as convenient as the old JGA-502.
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Offline Mark Scarborough

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Re: Gravity Feed Spray Guns
« Reply #5 on: December 19, 2013, 11:19:11 AM »
yep what Bill says,,
was your Iwata a full size gun, or a detail size,, I have one of the Iwata detail guns,, it atomizes wonderfully,, but its not suitable for clears or single stage materials,, its awesome for base coat colors ( in a two stage system, base clear), then I use my Sata minijet for clear which is bar none the best most  reliable gun I have ever sprayed with,, but like you say,, filling it is  interesting even with a stand,, I made my own stand that wraps around the cup,, and has sides to capture the grip, its bullet proof now too,,
I started with Sharpe  guns,, then got a DeVilbuss JGA ,, it was a very versitile gun ,,
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For years the rat race had me going around in circles, Now I do it for fun!
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AMA 842137

Offline billbyles

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Re: Gravity Feed Spray Guns
« Reply #6 on: December 19, 2013, 04:51:00 PM »
Quote from: Mark Scarborough on December 19, 2013, 11:19:11 AM
yep what Bill says,,
was your Iwata a full size gun, or a detail size,, I have one of the Iwata detail guns,, it atomizes wonderfully,, but its not suitable for clears or single stage materials,, its awesome for base coat colors ( in a two stage system, base clear), then I use my Sata minijet for clear which is bar none the best most  reliable gun I have ever sprayed with,, but like you say,, filling it is  interesting even with a stand,, I made my own stand that wraps around the cup,, and has sides to capture the grip, its bullet proof now too,,
I started with Sharpe  guns,, then got a DeVilbuss JGA ,, it was a very versitile gun ,,

Hi Mark,

My Iwata was a full-size gun & I guess I just could never figure out the combo for it.  I lost patience & went to the DeVilbiss JGA-502 which is now, unfortunately, obsolete for use in a commercial shop (at least here in Southern California.)  My full-size Sata Jet guns are the bomb, although I am going to do what you did & make a good stand for filling the cup.  You ain't lived until you have had a gravity gun tip off the stand & dump a load of catalyzed polyurethane all over the bench...what a mess & expensive too.

Come to think of it, could you send a photo of the stand you made for your gravity gun?  Maybe I won't have to re-invent the wheel, once again.  Thanks.  My email is w_byles(at)msn(dot)com.

Bill
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Bill Byles
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Offline Mark Scarborough

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Re: Gravity Feed Spray Guns
« Reply #7 on: December 19, 2013, 07:09:46 PM »
I guess I have lived then,, not only did I loose the gun ( with a full cup) but it took out the mixed two quart container of clear next to it as well,, oh and of course,, the car was scheduled for delivery the next day,, and this was in the late afternoon,, sigh,, I invented some new combinations of words,, I did mention I was also almost out of clear and catalyst as well right?
I will see if I have a pict,, I dont do paint for a living anymore, basically I just modified a normal stand with side plates tack welded on so the handle could not slip sideways,, of course all of this was AFTER the little spill incident
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For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Offline Steve Thornton

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Re: Gravity Feed Spray Guns
« Reply #8 on: January 21, 2014, 12:01:37 PM »
 I ran across this YouTube video and it is very educational for us who are new to spraying. Tell me what you think.
Steve

Harbor Freight HVLP Spray Gun Modification THE CHEAPEST HVLP EVER

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Offline Mark Scarborough

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Re: Gravity Feed Spray Guns
« Reply #9 on: January 21, 2014, 01:18:34 PM »
personally,I have said it before, and will say it again,

how many hours do you have invested in your airplane before you paint it,, is it worth using substandard equipment, and chancing screwing up your work when you KNOW the gun has issues,, if the machining on the outside of the gun is screwed up,, how well do you think the inside is done?
seriously,,
for $100  you can buy a FINEX gun that will do a stellar job every time,,
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For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

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