Hvlp versus conventional spray gun

I have been messing around with autobody and paint for about 40 years now. Many years ago when I learned to spray it was with conventional siphon feed guns. Over the last 10 years or so everyone has gone to HVPL guns. With the high cost of materials I attempted to switch to the HVLP type gun.

I knew that there would be a learning curve. I have sprayed many parts with the HVLP gun and can tell you that I just don't seem to be able to flow the paint the way I can with a conventional gun. The feel is totally different and when overlapping my spray patterns I can't get the paint to lay down as compared to stuff I spray with a conventional gun. I have messed with the settings and read several articles to no avail.

Anyone else experiencing the same difficulties? For the record I use an Optima 500 gun which is produced in Germany. It is a reasonably priced gun that was recommended by a friend who is a professional painter at a shop and sprays every day. I can't justify the cost of an Iwata or Sata.

 

Look forward to the replies, I'm old school never had a chance to use a Hvpl gun. My guess is that would be great to use painting wire wheels.

 

I agree there is a bit to learn when switching to an HVLP. I'd suggest to get your painter friend to give you a bit of instruction. If he paints daily he will be able to address your issues and save you a ton of time and headaches! Once you get the hang of it you'll love the HVLP!!! Good luck! What type of paint are you spraying??

 

Not a career painter, but went to school for collision repair and worked in it for about 6 years overall. I learned using both. The HVLP gun was a DeVillbiss siphon feed, though. I didn't have trouble switching between the two, but recently, I picked up a gravity feed HVLP and it is kicking my ass. I think it has to do with the pressurized cup. I would love to have another siphon feed HVLP, but I will be cautious buying any gravity feed gun.

 

Just in general it seems that painting is more difficult than it used to be.
I started out years ago with a old/cheap hand-me-down gun, junk compressor with no water traps or regulator and using Delstar products and it seemed like I could do no wrong - everything flowed out nice and glossy and everybody wanted me to paint their stuff for them. It seemed effortless to get great results.
But then, each time I made a step up to better equipment and newer products, the more I began to struggle.
I feel sorry for painters trying to make a living with the products available today - you really have to be on top of your game to get a good results now.

 

my biggest adjustment was having the cup blocking my view. once i got over it, i really fell for the HVLPs i still use a siphon feed for primer though. the gravity gun is also more comfortable when im reaching over roofs, with the weight being above my hand instead of under it.

 

I'm not going to read the other replies,,first,,, I'd like to hug you,,lol.I have the same sentiments.
I've been painting since 1978. I bought a HVLP in '88 and fought with it. I played around with different combo's and settled on the largest cap they made. That seemed to help. I was mostly shooting Diesel's with DuPont Polyurethane and BC/CC. My foreman 20 years my senior said it was all hogwash and to use what works. The finish was more important than "solvent bounce". I haven't touched that gun in 15 years or more. I'm set in my ways and I still use my DeVilbiss JGA. I don't know how the water based paint will play out though. We have a few shops here using it.

 

Paints nowadays are FAR superior to the finishes 20 years ago.

 

I painted cars and parts with a binks 7 gun for a long time on most of my projects but the new guns use way less material. The only thing I dont like about the new guns is the trigger feel. The trigger feel is better to me from the binks but then again the paints of the day you dont need to paint like you did back in the day. Wet Sand....Buff? Shine came from the can from a real painter back in the day. It was hard to take enamels "House Paint" and make it look like show paint without wet sanding and buffing. My binks #7 still seems to put down clear better but I would have to fool with nozzle sizes on the Hvlp. I wish the trigger had a better action, just not on and off. That is my opinion but I didnt paint every day. ...But I did stay at a Holiday Inn Once....LOL. RD

 

Yes,,,,but more difficult to master

 

MarkRodz,
It is funny that you mention the Devilbiss JGA. That has been my favorite gun for years. As I struggle to adapt to the HVLP I will shoot individual panels with it but if I need to turn something out that is show quality or paint an entire car, I always revert to my JGA.

 

I too have sprayed a conventional and the HVLP is another animal. For me, I like the way an RP (Reduced Pressure) lays down. It still has the speed and layout of a conventional, but is compliant. Mine is a Sata RP 3000, the 2000 is still a great gun as well, and I'm sure other companies make something at least similar.

 

I am a painter by trade (not that means anything LOL) . i agree with olddrags. Go see your painter buddy and maybe ask real nice to go into the booth with him and just watch his overlap, pressure and gun distance from panel. I personally like a bit more than recomended pressure and hold the gun pretty close to the workpiece but just move faster at the same time. I use an Iwata LPH400 and a Sata NR3000. But Honest opinion is any gun no matter the price will put down a beautiful job, it comes down to getting comfortable with your gun.

 

when i first went to hvlp i didint like them much either.

i know i bought 20 or so different guns when they first were introduced.

after a bit of use, like anything else, you get used to them, and trust me they work much better.

i use various types for different jobs, but once you are used to the gravity feed they are hard to give back. no cup leaks, no hittin the bottom of the cup on the paint, etc.

for certian things,such as flakes the gravity feed doesnt work so well.

for big primer jobs, the ones with the pressureized cups sure put out the material



skull

 

"i know i bought 20 or so different guns when they first were introduced".

skull

That's what my foreman said in a meeting,,,,was the pitfall that his employees were to avoid,,,,,that you keep buying "The Gun of the Month" and pay out thousands when you just needed to spray the paint and get a nice finish preferably without sanding and buffing.

 

Gravity feed HVLPs are great. My biggest piece of advise is "AIRPRESSURE", read and check it.

 

I sprayed with a Devilbiss MBC gun for years and then when the non-HVLPs were outlawed I went to a Devilbiss Millenium and have been very pleased with it. I especially like the "zip lock bag" in the can...never a drip and easy to clean up.

 

Do you mean less pressure or more?
I have a gravity HVLP, but when I set the air pressure according the manufacturer's instructions, I can hardly get anything out of the gun - very dry no matter what I set the controls to. Seems like I have to run twice the pressure they recommend in order to get a decent amount of product out to be able to flow into itself.

 

Check the paint manufacturers recommendation. Each one seems to be a little different, water borne (from my little experience) required more pressure. I would also get something to do a lot of spray-outs on. it takes a little to get the fluid and air to jive together.

 

Most likely they are calling for air pressure measured at the cap. So, say 30psi at the gun yields like 20psi at the cap. Most HVLPs seem to be happy right around 20-22psi or so at the gun. I run my RP at 30-32psi at the gun. Also measuring the pressure at the hose hookup will yield a pressure drop at the gun and even more at the cap.

 

The HVLP stuff I've used has been with the TiP tools self contained turbine systems. I love 'em. I don't consider myself a good painter, but even I can lay on a nice coat with one of those things. Takes out all the variables of compressor type and CFM, as well as humidity and crap in the lines. Plugs into a 110 outlet. My only problem is that I've always borrowed/used my dad's, and I now live an hour away. Time to nut up and buy my own...

 

Now that's something I wasn't taking into consideration.
That is helpful - thanks man

 

Then how come the "single stage" acrylic lacquer I sprayed on my 40 GMC in 92 still looks way better than the crap clear that's peeling off my (made in Ohio by Americans) 96 Civic?

The new stuff is house paint* with liquid saran wrap sprayed on top....For a while.




* Actually, since base coat can be thinned with lacquer thinner, it's probably a flat lacquer.

 

thats because the ohio plant improperly applied the paint, as did all the other manufactures in that era.

the paint suppliers went to the factories and touted there new systems that would eliminate one of the steps prevoiusly used.

as we all know now those jobs failed, and up till '06 or so, the factories were left holding the bag, and paid for billions of dollars worth of re-paints. i did hundreds of them my self, even as an independent shop gm was so overloaded they farmed out alot of the work.

it goes without saying that the modern systems are far , far superior to the old stuff, but just like them, must be properly preped and applied or are subject to fail.

as you say , some base coats are universal and are similar to lacquer, but without some of the bad qualities. when thinned with lacquer thinner , lacquer clear can be used, and you basiclly have a lacquer finish. you cannot spray them as a single stage though, as you could with lac, unless you use special binders (some systems , not all have this option)


skull

 

My problem when I made the switch is I kept getting this wicked bad texture to everything I painted. I tried higher pressure, lower pressure, different tips....I finally got pissed and threw in the towel and went back to my trusty old JGA and a porter cable gravity feed that is conventional. I'm a painting fool again and can lay down pearls, metallics, whatever with no problems and get a great finish.



I used a porter cable gun and SUMMIT paint on an O/T truck. Shit sprays pretty good, but if you use it make sure and clear it. The gloss was definately lacking before I cleared it even though it is "supposed" to be a single stage.

However, if anyone wants there home walls textured give me a call and I'll dust off my HVLP

I started a review on the paint if anyone wants to read it, go here:
http://www.jalopyjournal.com/forum/showthread.php?t=427215


scot

 

In durability of course urethane is a better choice. What looks good is up to opinion, who sprays it and how well you manipulate the system to get your color. For custom paint there is huge selection of candies,pearls, dyes, and additives to play with to make what you want. Otherwise modern paint looks like pixels on a cheap TV.
Nothing today looks as clear, bright or deep as lacquer or even solid color enamel. Put a 40-50 year old and less than perfect paint chip chart next to it's modern counterpart on a test panel just for fun. You won't see four specks of filler and resin for every color pigment or metallic chip like on your urethane test panel. Duplicating vintage Factory colors is the real problem and is often just shy of impossible with what we have to play with now. Red seems to be the worst, when the lead went away so did the color... I'd love to find Roman Red that looks like OE from 59.

For what it's worth still I prefer the way a conventional gun lays down metallic. I use do HVLP for most solids primer, or basic repair work but I still prefer a standard bottom cup on a full size gun over a gravity feed. It also should be noted that not all gravity feeds are actual HVLP guns.

Inspite of the regulator on the gun your running line pressure can make a huge difference with tuning a HVLP and some are more sensitive than others. Going from a shop with 125-140 psi of constant heated air to a worn compressor kicking on and off pushing 90 often requires alot more effort than just twisting the regulator. I had a small shop I did some sub contracting to years ago, it was nice setup but getting a gun just right to accept the varying pressure was a pain.. With a conventional gun it was no problem, but it also varies gun to gun. I had alot of luck with a beat up Accuspray that had been tossed aside but the guy's brand new Sata I just could not get to a point where it was consistent.

 

Orange peel is there, by design, to match the factory applied finish.

 

i have an acuspray 9000 and i love it.only 5-9 psi and fed with 3/4'' line.its a siphon fed pressure cup.i can spray some 50/50 lacquer and paint mix,lats out great.put some straight clear and 4 tablespoons of flake and spray.i have used reg.conv.guns but i will never paint a whole car with one again.my friend came over to my shop many years ago to watch me paint one of my cars and was so amazed at how nice it layed out with next to no bounceback.he was standing about 10ft away and didnt need a resperator.he ended useing my setup for about 6 months insted of his $650.00 new dev.hvlp.

 

With my HVLP gun I use 30 to 40 psi inlet pressure. The gun internally regulates this down to the proper tip pressure. Wasted some really expensive paint before I figured this out. It wasn't mentioned ANYWHERE in the friggin manual. I forget where I wound up finding this information, but it wasn't from the gun manufacturer.

 

I've sprayed quite a few cars with those turbine units. They work nice for metallics as already mentioned. One serious adjustment you have to know in order to get good results is to use a slower reducer. The heat of the turbine air makes this mandatory. Plus, weather conditions and temperature will affect the percentage you use too.