HVLP painting gun question

[Jay4200]

I'm thinking of getting an inexpensive HVLP spray gun for a little tractor-resto work. The gravity-feed HF guns have gotten glowing reviews. They sell two, one with a regulator and one without:

Gravity Feed Spray Gun - 20 Oz. HVLP

HVLP Spray Gun w/ Gravity Feed

Any comments on which would be better? Is the on-board regulator necessary or at least useful? What are the advantages/disadvantages of either?

Thanks - JayC

 

[Soundguy]

i personally dislike the gravity feed guns and prefer the screw on cups as I paint a few odd angles sometimes that makes a gravity gun leak from the top of the cup. however price range is similar. I don't own a paint gun that cost over 24$

I have a CH pressure gun, a 4 oz syphon touch up gun.. an old gun i use for primer, plus a new ' industrial' quality I use for paint.. most of mine are syphon ( I like them for some reason ).. but do use 1 hvlp as well. all aly paint.. the syphon use more air.

you need a regulator either on the gun or at the compressor.. so you can set air pressure.

don't be fooled. even a 15$ gun can make a great looking paint job. it has more to do with the prep and technique, then the gun or the paint.

as I've said many times over on other antique boards.

26$/gallon paint sprayed thru a 15$ gun via a 3hp / 3og / 1 stage 150$ air compressor, onto tin that has had 40 hrs of prep work and elbow grease will give you a better looking paint job than 200$/gallon hot rod car paint, sprayed thru a 250$ binks gun, via a 900$ 5 hp / 60g 2 stage compressor, onto tin that's had 20 hours of prep work.


soundguy

 

[Farmwithjunk]

I'm one that's on the side of HVLP gravity feed guns. Siphon cup guns will dribble paint when held at odd angle also, through the vent on top of the cup. Trick is with ANY gun, keep 'em back away from your target when holding gun at weird angles... It's all what you get used to...

I have a couple "Huskee" guns (Home Depot) that were around $60. Also have a Sharpe platinum gun that was around $300 IIRC. The more expensive guns seem to handle "high tech" paints and finish's with a little more consistency, but as Chris eluded, it's MORE about technique....Practice...Practice...Practice....

I compare paint guns to golf clubs...Not every club fits the style of every golfer. Same applies with paint guns. Find yourself an automotive paint vendor if you can, and let them walk you through the various types of guns. You're under no obligation to buy one, just let 'em know you're "shopping" but maybe not BUYING....Most will be glad to show you the ropes.

A reg is essential. I DO NOT like 'em hanging on the gun. Extra weight can be cumbersome after prolonged use. I have a reg on my compressor, and will sometimes put one in line, a hose length away from the gun when I feel the need to "micro manage" air pressures. (when painting large surfaces AND small parts at the same time)

Get a GOOD water trap.

Make certain your compressor has enough cfm's to keep up with the gun. There's another BIG plus with HVLP guns....Lower air usage. HVLP guns will also cut down considerably on paint usage with a LOT less over spray. MOST of your paint will land "on target" as opposed to settling on the floor.

Get a GOOD mask, use proper ventilation. I have some symptoms of asthma which ISN't asthma....It's the effects of icocyanites (sp?) the catalyst in paint hardeners. It took ONE SINGLE EXPOSURE, less than 10 minutes......Some people are FAR MORE prone to the effects. Once you find out you're one of the lucky ones, it's already too late.

Get yourself an old car hood, or some similar piece of sheet metal. Practice on that. Try your paint/thinner/hardener mix.....Try your technique....Better to mess up that than the hood on your prized antique tractor......BTDT, sanded off a few horrible runs.....


Prep is EVERYTHING as Chris stated. Paint is NEVER any better than the surface it's applied to. CLEAN everything.

Tip of the day....NEVER allow ArmorAll NEAR your paint shop....Trust me on that one. Leads to heartbreaking results, let me tell ya...

 

[Soundguy]

ditto that 100%

especially the water trap. Do also drain your comp regularly ( should be anyway ).

aslo.. have a set of dedicated hoses you use for painting IF you have an oiler inline.

IE.. don't use hoses that have had oil run thru them.. and do not use an oiler with the paint gun that's when you will get to learn about fisheyes and such... same with FWJ's armor all comment.. silicone makes great paint dispersant...

soundguy

 

[Mighty Dodge]

I'm by no means a professional painter but I bought the hvlp gun from Harbor Freight and find it easy to use and clean up.
HVLP Spray Gun w/ Gravity Feed

 

[deereman75]

That reminds me, I have to try out my princess auto $12 sale touch up gun...

 

[Jay4200]

you need a regulator either on the gun or at the compressor.. so you can set air pressure.

Obviously, but can a compressor regulator do the job adequately? What kinds of pressures do HVLP guns run normally?

I have a fairly nice gun out in the garage, although I've only done one major project with it (painted a 35' trailer frame), but I have never used an HVLP gun.

JayC

 

[Car Doc]

Id get the reg on the gun on these cheap clones they dont last forever. A good reg is twice to 3 times what that whole package is so you are not getting hurt at all.

Plus they run at such low pres 30-35 its better to have it on the gun and be done so you can right away go paint something!

HVLP is the only way to paint now days especially when automotive paints and 2k primers and 3-4 part urethane clears etc can get up to and over $600 a gallon you want every drop on the car etc not in the air or floor. :thumbsup:

 

[Soundguy]

the reg on the gun makes it a bit clunkier. and how much quality is a reg on a super cheap gun.. it's likely only an orifice setup anyway.

the reg on my compressor works FINE for painting.

soundguy

 

[tcartwri]

..I have a couple "Huskee" guns (Home Depot) that were around $60...

I have used these guns a couple of times now too, but I found that I had to set the regulator to 35 to 40 psi to get the gun to work properly. Not sure why they are called HVLP. :confused2:

 

[Soundguy]

I have noticed the cheaper hvlp guns do use a lil more air than a high dollar hvlp.. almost as much as a syphon gun.. maybee 15 psi less... however... they still make less overspray and DO put alot of paint on target. a syphon gun can't touch the amount of paint on target that a hvlp layes down.

only thing i've seen that lays more paint is a pressure pot gun..

soundguy

 

[Car Doc]

Sound guy,

I have a regulated air supply in my paint booth but I still use a reg on my guns and the un-regulated supply line while I am in there.

I have found the reg on the gun is so much better control of the spray pattern as long as it is a good working one. I have a bad one on my clear coat gun right now I am probably going to throw it as far as my bad shoulder will let me next time I use it.

I think its a matter of hose flex when I let off and get back on or something that allows the pressure to fluctuate but I can very definitely tell the difference. as always ymmv

With that said a 17 dollar reg is a 17 dollar reg same as a 17 dollar hvlp gun does it compare to a $450 Sata or Binks no heck no its not meant to.

 

[Jay4200]

I have used these guns a couple of times now too, but I found that I had to set the regulator to 35 to 40 psi to get the gun to work properly. Not sure why they are called HVLP. :confused2:

I was wondering the same thing - I saw a poster giving a review give the same 35-40psi numbers (which puts it well into compressor-regulator territory). OTOH, it certainly isn't the 90psi or so that the siphon guns evidently need...

One thing I learned (after blowing through a gallon of paint at about 3% transfer efficiency) was that the paint transferred better with higher pressures. I expected the opposite and kept turning it down - I figured the crappy transfer was the way it was. I wouldn't have ever figured it out, except I turned the pressure up way up by accident, and the paint suddenly started go actually go onto the metal instead of just foofing off into the atmosphere. Once I cranked the pressure up, the transfer was pretty good. The second gallon covered 3-4 times what the first did. Unfortunately, I don't remember exactly what pressures I was running, but I think it was up near 90 - it was a few years ago.

JayC

 

[Soundguy]

that's kinda my point..it's a 17$ gun.. thus a cheap reg is about all ya need

i've always found having a reg on the gun effects me moving the gun due to stiffness of the hose past that. but as another member said. That's likely more of a personal choice issue.

soundguy

Sound guy,

I have a regulated air supply in my paint booth but I still use a reg on my guns and the un-regulated supply line while I am in there.

I have found the reg on the gun is so much better control of the spray pattern as long as it is a good working one. I have a bad one on my clear coat gun right now I am probably going to throw it as far as my bad shoulder will let me next time I use it.

I think its a matter of hose flex when I let off and get back on or something that allows the pressure to fluctuate but I can very definitely tell the difference. as always ymmv

With that said a 17 dollar reg is a 17 dollar reg same as a 17 dollar hvlp gun does it compare to a $450 Sata or Binks no heck no its not meant to.

 

[Car Doc]

Yup and like you and a few others have said a good paint job its more in prep than paint gun anyway at that point its operator skill how he makes the paint go on not with what. :thumbsup:

 

[bjr]

I have the HF HVLP gun and like it just fine and I'm just a guy that tries to paint some implement about once or twice a year. I've painted my propane tanks as well. What catches me every time I go paint is the orifice section in the gun where the main needle goes is always plugged with hardened paint. Yes I try to clean the gun after every use. I get the paint to flow and do okay then but still get a lot of runs. bjr

 

[ray66v]

I have used these guns a couple of times now too, but I found that I had to set the regulator to 35 to 40 psi to get the gun to work properly. Not sure why they are called HVLP. :confused2:

Like many things in the refinishing industry, the name and the wording are confusing.

The low pressure aspect is at the output of the air cap. A professional HVLP gun will put out about 10-12 psi at the cap, with 30-50 psi going into the gun

Most HVLP guns do a very poor job of atomizing the paint if you do not run them at high input pressures. If you don't atomize the paint, it generally won't lay out real flat, and you can have problems like solvent popping with automotive finishes.

It's not an airless. They still can make lots of over spray at those pressures, due to the volume of material transferred, forget the no over spray myth. The best way to reduce over spray is to learn to apply paint on the item your painting, and not the air. This means finding the correct distance, learning to control the trigger, and aiming properly. With practice, your transfer rate will increase.

A good rule of thumb when determining the best pressure for a given gun is: With material in the gun, open the fan control all the way and spray the gun into the air. While spraying, increase the pressure until you see the spray pattern, (we call it the fan), go from a nice oval to a distorted shape, decrease the pressure until it goes back to a nice oval. Note the pressure at that point. This is usually the pressure that will give you the best atomization with that gun, which will usually result in the nicest paint job.

Gravity feed HVLP guns are designed for applying high solids automotive materials. If you are spraying other products, you can actually use a traditional spray gun, make less over spray, and do a great job.

 

[Soundguy]

I have the HF HVLP gun and like it just fine and I'm just a guy that tries to paint some implement about once or twice a year. I've painted my propane tanks as well. What catches me every time I go paint is the orifice section in the gun where the main needle goes is always plugged with hardened paint. Yes I try to clean the gun after every use. I get the paint to flow and do okay then but still get a lot of runs. bjr

you pretty much have to clean the gun fully after each use.. down to spraying on a white cloth till no more color shows int he napth running thru it.. then wipe down exterior and clean cup too.

runs are bad technique, too thin of paint, or too much paint ( and 5 other things too ).


soundguy

 

[Jay4200]

Gravity feed HVLP guns are designed for applying high solids automotive materials. If you are spraying other products, you can actually use a traditional spray gun, make less over spray, and do a great job.

Are you saying that will a thinner paint, a regular gun will have better transfer efficiency? I suspect I'd be spraying low-cost oil-based paint, such as Rustoleum enamel.

Is it even possible to properly prep a surface without a sandblaster? I'd like to avoid using one, but wonder if I'm just wasting my time.

JayC

 

[ray66v]

Are you saying that will a thinner paint, a regular gun will have better transfer efficiency? I suspect I'd be spraying low-cost oil-based paint, such as Rustoleum enamel.
JayC

You can spray industrial enamel like Rustoleum with any kind of gun, you would have to reduce it to the right viscosity.

House paint, and industrial enamel are a little on the thick side so they do spray better with a gravity feed gun, a pressure feed, or airless. These kinds of paint don't need to be atomized, so you can use a lower air pressure, and let them flow out. But, if you add enough reducer, you can spray them with an old siphon gun.

Lighter products that are mostly solvent, like: Lacquers, stains, varnishes, and acrylic enamel, will all spray better in a convention gun.

Is it even possible to properly prep a surface without a sandblaster?
JayC

Yes, no, and maybe. This depends on an awful lot of things.

Sandblasting an item of any kind of size requires a good sized compressor, a good air drier, and the right media.

If you sand blast it with crude basic equipment, you could end up blowing water vapor all over, and it could begin rusting before you even finish it.

There are lots of way to prep something for paint, from a simple cleaning and scuffing, to using a wire wheel on a grinder.