What psi HVLP gun

[poida]

Hi,

I have had a few different responses from people and was wondering what to set my compressor when using a generic HVLP spray gun. I was told around 40 psi but it seems that the gun has a very narrow fan at even full adjustment. I read somwhere to set the compressor at 90psi and this does improve the fan control significantly and it looks like a lot more paint is being sprayed (HV- high volume). A higher psi seems to be the way to go, but i want to check.

I understand the LP (low pressure) means that the gun is capped at 10psi and i definitely see a lot of paint existing the gun when the compressor is set at 90psi. When i thought low pressure i thought you set the compressor at a lower pressure, and I was wrong.

Also i do not have a regulator just prior to the gun so i am leaving the airflow adjustment on the bottom of the gun fully open and then going on the psi that i have set the compressor to.

I ask thees questions as i am having some average results and seem to be getting a lot of different advice.

So what should i set the psi on my compressor? What about on the base of the gun?
Any advice is great as my neighours seem to be bitching about paint smells and the backyard is looking a nice frosted white

thanks

[oldcorollas]

nicked from here http://www.woodworkforums.ubeaut.com...hp/t-6734.html

Gun set up involves balancing air pressure at the tip centre, with air pressure at the tip horns, with fluid delivery. If you were to point the gun at a piece of card, with the gun arround 20cmm from it and pull the trigger briefly, with paint in the gun, you should see the paint form a fat cigar shape. This indicates that the gun is set up correctly. If the shape is an oval this would indicate that there is not enough air pressure at the horns. if the pattern is split or narrow in the middle, this indicates that the air pressure at the horns is too high.
A good start point for set up would be:- Fluid 2 turns out from fully closed, Fan control (Horn Pressure) half open from fully closed. Air pressure really depends on the type of gun you are using, HVLP 30 psi inlet, RP 30-40 psi inlet, Conventional (high Pressure) 40- 65 psi inlet.

it should be able to do high volume even with a lower pressure... as it's the volume of air, not the pressure, that makes it work the way it does...

[poida]

Cheers,

i have read that article and i understand the fan setup, but when they talk abiut 30 psi inlet are they referring to a regulator that i do not have installed? I'm unsure about what to set my compressor to... and there definitely isnt enough air at 40psi and i'm wondering if 90 psi is too much

Pressure Adjustment: Open your compressor regulator up so there is plenty of air pressure in the line to the gun (I set mine to about 90 psi). Next set the regulator on the gun handle to 50 psi (what I use for DP40 and K36) with the trigger pulled and leave it set there.

http://www.purplesagetradingpost.com...Pspraygun.html

[love ke70]

55 psi works well...
p.s. didnt read the rest of the thread

[oldcorollas]

what size tank is it... and does the compressor flow enough AIR to cope with a HVLP?

[love ke70]

im runnin a 40 litre dodgy spec compressor and it flows enough
thats the beauty of those guns
maybe you need to put more paint thru poida? play with the setting with the regulator on around 55 pounds

[allencr]

How big & long's the hose?
You'd be surprised at the drop the common red 1/4in x 25ft stuff has between regulator & tool.

[poida]

love ke70, oldcorollas, allencr :

thanks for all the advice, you have been a lot of help. It isnt the best spec compressor by any means but is fairly big and should atleast cope to do a panel at at a time at worst.

Yes the hose is around 30 or so feet, and i just checked that the connection seems to be leaking if on a particular angle. oh no!!!! god save us!!!

Thinking about it more, the artilce i read about 90psi makes sense as the person is using a regtool just before the gun which i dont own, and im sure that would be at a much lower psi, probably around the 55 psi as mentioned. Really all i was interested is what other ppl use, 40 didnt do it for me and yes i guess i missinterpreted 90.

I will play around with the settings around that psi and let you know in a few days. Sucks having to mix the paint up, test, clean up, then see the results the next day...

Anyways cheers again

[oldcorollas]

do a rainbow test panel with different settings for each strip (write em down first ) and see what looks best

[takai]

I was doing some stuff with my cheapy GMC little unit which i take to the track today. 55-60psi and it came up beautifully. The only problem i was having was keeping enough paint in the gun, stupid suction fed guns.
I want my Star HVLP back

[poida]

do a rainbow test panel with different settings for each strip (write em down first ) and see what looks best

I can see it now the benetton celica

[poida]

Well the results are in, 60psi and paint thined 30% seems to have provided some good results.

Although my pure uncon-ess has caused a few drips from not doing the paint lid on the gun properly, closelly followed sweat dripping from my gloves and a few bugs landing on the surface. A few touch ups might be applied if i can be bothered. I swear to never to this in a backyard again!!!

But overall the paint finish looks quite good in my opinion, and after all this car certainly get cained with what i hope to do with it so eh. Cheers for the info

[vanman]

by thinned 30% do you mean 1 part thinners 2 parts paint? or 3 parts paint?

just about to start playing with my own gear, so time to learn how...

cheers
vanman

[poida]

Hi, if i had 1L of paint and hardener then i would add 300ML's of thinners.25%works well as well and was on my spec sheet.