Oct 25, 2007

How to dial in HVLP Sprayer

HVLP air control and fluid knob Some guys struggle with the HVLP (High Volume Low Pressure) sprayer. I think if more guys felt more comfortable about how they work, more guys would use them. For the purpose of this article I will be using the ICI Sanding Sealer only because I happen to be shooting it this week.

On the HVLP gun (top photo) you see two dials, the top one is the air flow or air control knob (how much air goes through the gun) and the other is material flow aka fluid knob (the amount of paint passing through). The arrow on the upper knob (air flow) is set at about the 7 o’clock mark. Max air flow is at 12 o’clock. The knob only works from the 12 o’clock to 6 o’clock mark but you can turn it either way. So if we turn the knob to the right to 5 o’clock, it is the same as turning the knob to the left at 7 o’clock. Hope that makes sense.

The photo below shows how thin the material is. Do you know how -when you pour thick paint in a bucket, the paint sort of accumulates on the surface before it levels out? We can’t have that happen with an HVLP. The paint when poured into itself should dissipate immediately into itself. I have my sanding sealer a bit on the thin side but not by much and only because I was shooting a light dusting coat of tinted sealer.

HVLP cup Once the paint is mixed up and in the cup, turn the fluid knob all the way in and then back it out 2 full turns. Start by shooting with the air flow at the 6 o’clock which should be ‘OFF’. Then while squeezing the trigger, start by turning the air flow to the 9 o’clock mark. It should produce paint at least air through the gun at this point. If not, turn the fluid knob another full turn out. If still nothing, your material may be too thick. You can at this point open the air control knob all the way to 12 o’clock to confirm. If still no material, the gun is blocked up or material is too heavy.

If all goes well, you should be able to shoot materials through the gun with the material flow open slightly and air flow set at 7 or 8 o’clock. 12 o’clock is overkill and does nothing but cloud up the room.

Assuming you have paint through the gun, turn the air off again and very slightly turn air pressure up (a hair) or until paint is distributing a fine spray pattern. If you cut off the air flow the gun should spit paint out. Dial-in where the minimum air is needed to shoot a fine spray from the tip of the gun. The knob is very sensitive, use very small increments for adjustment.

Once you get the hang of that, you can adjust the fluid knob more to move materials quicker. When shooting heavier materials you may want to convert the gun to bleeder style.

See also: HVLP Maintenance and HVLP Transfer Efficiency


Xiz said...

Thank you for this post. Very little information is out about these great little sprayers. I recently bought a Kobalt (Lowe's) unit for $54. It came with instructions which were terse to say the least.

I've been mining the internet and it isn't much better. I've figured some out by tinkering. This was a really helpful post. I'm just getting started learning the ins and outs of painting. Most of my expertise is drywall and finish carpentry. Lots and lots of people want painting work done and there is a shortage of painters around here. People don't like to cut-in.

I have discovered how to do it with my HVLP, so the brush has almost no use left in my tool inventory. It's faster, less fatiguing, and uses less paint. Oh, it's also easier to clean - my gun is less complicated than yours.

Please keep posting about this great tool.

Bj said...

Same as previous post. There isn't much out there in the way of "how to use an HVLP" and even though I am using a totally different gun than yours-your information was very helpful! Thanks. Bj