PAINT GUNS

[JACK34]

I have working on my truck, got a new box and plan on painting the whole truck next spring like hot rod matte black type finish. Anyway I have been experimenting with 2 cheap HVLP guns spraying automotive epoxy primer in one and Rustoleum in the other gun. Both 1.4 tips. They seem to work good paint looks good even though I'm not a painter, pretty easy clean up. I like them.

Here is the thing. Back when I had some older mid 70's trucks I painted them with conventional siphon fed guns that I still have. So I started to think why is HVLP better or maybe it's not.

So I did a small amount of research and the first that came up was EPA regs. The old guns were blowing paint all over the place so I guess some laws were put in place. The 2nd thing that came up was people are saying the old guns spray better. Less orange peel, smoother finish. Yes you are losing paint I understand they are not as efficient. And don't get caught using it in a body shop I get that.

Well It got me wondering what's true so I purchased a cheap siphon gun with a 1.8 tip and the cup matches up with all my other guns. I cleaned up one of the BINKS guns I have and it seems to be good to go. Just spraying solvent through it for now. Going to shoot some paint this weekend and find out.

Just curious what you guys think about these different paint guns. What's the truth?

 

[RichLo]

I've used both a cheap syphon gun and a nice 3M HVLP. The syphon gun laid it on thick and used a ton of paint compared to the HVLP. I used up a whole gallon (after reduced and hardener added closer to 2 gallons) after 2 coats on my snow plow truck with the syphon gun. That same amount of paint painted both my yard truck AND 1000 gallon propane tank with some left to spare with the HVLP.

 

[stutaeng]

Yes, it's true. When HVLP came out it was all rave because of the "high transfer efficiency." People still think it's the best thing since sliced bread, mainly because the name stuck on.

Later they came out with RP (Reduced Pressure), "complaint," or sometimes also called "Trans Tech." They use a bit higher pressure than HVLP and the transfer efficiency is a bit lower, but they atomize the coatings better, especially the newer, high-solid clears.

I've got 2 nearly identical spray guns made by CA Technologies, one is an HVLP and the other is a RP. The RP blows away the HVLP when it comes to atomization. I do mostly woodworking finishes and have sprayed waterborne acrylics and some 2k similar to auto finishes.

I've only done a hood and fender here and there on the auto side, so not much experience in auto finishing, and certainly not a pro. One common method is to use HVLP for primer/sealer and basecoat, then use the RP for clearcoat.

The older high pressure guns worked very well because the coatings back then had lower solids and thinner viscosity (more solvent), so they flowed out very well, and the higher pressure of the guns. I don't think "orange peel" was an big issue as it is today.

Why are you using rustoleum? The best advise comes from the products' technical data sheets BTW.

 

[TechNova]

I use paint guns alot, part of my job, from basic 3M Accuspray with disposable heaeds to high dollar SATA and Iwata.
I also had been using high presuure guns before HVLP came out. For automotive products, the high pressure guns are not even in the same conversation as HVLP. I can't even legally use high pressure. Finish quality is not about how much the gun will hose on, there are mil thickness ranges for each product, more can be worse. I have not been impressed with RP guns and find most painters I talk feel the same. Properly adjusted, the HVLP will atomize as well as the RP. COatings from other industries are not comparible to automotive coatings, they spray differently. In fact each product within an auto motive line will spray differntly.
HVLP will reduce pollution and reduce material cost, somewhere around 30-40% difference.
Siphon feed or gravity feed has nothing to do with whether they are HVLP, you can by either in both types.
OP you are using guns with two different tip sizes so they will not perform the same. Reaad the tech shhet for you product and follow it.

 

[JACK34]

I appreciate the feedback. Right now I'm experimenting. I can legally use high pressure. I'm not as concerned with pollution as some but I am with material cost. Rustoleum is 38.00 a gallon. I mixed 2 parts flat black 1 part gloss gray and sprayed a panel and it looks like a hot rod matte black. 5 parts paint 2 parts acetone third hardener. With the HVLP gun with 1.4 tip. The DYNACOAT C900 topcoat is 375.00 a gallon. Tech sheet says HVLP with a 1.4 to 1.5 tip. I'm going to paint the back of this panel with rustoleum gloss black from a can and put it out for the winter by a salt dome Snow, salt dust the whole winter. Starting Nov 1st until April 1st. See how she looks after that abuse. Thanks again.

 

[JACK34]

Again, I appreciate all the feedback. Correct me if I am wrong here please. Back in the 70's I remember my Dad had a friend that painted my brothers Nova II with Laquer and a high pressure siphon gun I assume thats what it was thats what it looked like. The gun I mean. He painted that car in his garage and it was stunning. My Dad used to carve ducks and he would use the high pressure guns and spray clear laquer on some in the basement of our house and they looked like glass. I remember those guns they were cheap from SEARS. This was the 1970s.

In the late 90's I painted some trucks matte black with Farm Implement Enamel with a cheap high pressure gun I got from Farm and Fleet. No idea what tip it is. I still have that gun. The paint turned out great. It was the hot rod look people are doing now before that was cool I guess. That finish held up great, it faded a little but it made it look better to me but it never rusted.

Now it's 2020 and from what I can gather a lot has changed regarding painting, products, guns etc...

I guess I need to get with the program here. It's not 1976.

Appreciate you all.

 

[TechNova]

I used lacquer when I started in a shop. High pressure gun, 5-6 coats, sand with 600 and buff. It would not hold up well, it was a 1K product. Like everything else, the technology changes and we dont want to go back. I wouldnlt want lacquer again any mor ethan I would give uo this laptop for black and white TV.

 

[JACK34]

When you say it did not hold up well what exactly did you mean?

 

[Hipster]

Another factor not mentioned is that hvlp guns are air hogs. That can make a big difference if painting with a smallish compressor.

I've painted with a bunch of different guns as well. A lot has to do with painting style. All I run now is Devilbiiss HTE guns.

 

[Hipster]

When you say it did not hold up well what exactly did you mean?

I think he was referring to lacquer paint jobs. They did not hold up well. A lot of effort and a year and a half later it's spider webbing/cracking. It doesn't take a catalyst/activator so there's little crosslinking between molecules. Lacquer is also very brittle.