I'm curious what you all shoot lacquer and shellac with. I know the HF HVLP setups usually come with a 1.4mm nozzle set, but I've also seen a lot of folks using a 1.3mm set.
What do you you all prefer?
[OP]
Member
I'm curious what you all shoot lacquer and shellac with. I know the HF HVLP setups usually come with a 1.4mm nozzle set, but I've also seen a lot of folks using a 1.3mm set.
What do you you all prefer?
Member
It really depends on the viscosity of the material being sprayed in combination with the specific gun. My two primary guns give me setups that range from 0.8mm to 2.5 mm and picking the right setup for a given finish is important in getting it to lay out well.
I also have the HF gun with 1.4mm setup as a backup. It sprays lacquer and polyurethane quite nicely. 1# shellac not so much. Household paint not at all.
Contributor
What Mark said. I spray Sealcoat shellac (2# cut) with my HF 1.4 mm purple HVLP gun and it does a great job. Most of the WB finishes I use, however, have too high a viscosity for that orifice, and I use a 1.8 mm gun with them. If I sprayed much paint, I'd want a 2.2 or 2.5 mm orifice.
John
[OP]
Member
Excellent feedback - thanks! It's such a confusing subject. I was talking on the phone the other day with a technical guy over at General Finishes. I was asking him some questions about their High Performance Poly product. He said he sprays that with a 1.3mm nozzle! I'm pretty sure that's a water-based product, although I've never used it before.
@Mark - 1# shellac is thinner than lacquer and poly, right? Surprised it doesn't spray well, or do you mean you need a smaller needle for that?
Contributor
Mark, he may spray HP Poly with a 1.3 mm needle, but I doubt he's using a gravity feed HVLP gun. More likely it's an air assisted HVLP set up. I've noticed that GF's recommendations are consistently too low for a gravity feed gun. They list the viscosity of HP Poly as something like 35 - 45 seconds with a #4 Ford cup. That almost makes with a gravity feed gun with a 1.3 mm needle, but every time I measure the viscosity it's more like 55 - 65 seconds and I have to use a 1.8 mm needle and thin it 6% to get it down to 45 seconds for it to spray well. HP Poly is great stuff, very easy to spray, but you will have a hard time with it with the 1.4 mm HF gun. I like Enduro Clear Poly much better, better durability and sprays just as well without thinning; still with the 1.8 mm needle though.Originally Posted by Mike Dowell
John
[OP]
Member
@John - Looks like I need a quick lesson. I just realized I'm confused about this. So, the guy at GF DID mention using an air assisted unit. I guess I was just having nozzle diameter tunnel vision. So, not all sprayers are the same, even when they have the same nozzle size. QUESTION: is my Earlex 5500 an air assisted unit? I guess that just means that the cup is pressurized - right?
So here's the thing... How do you know what tip size is right for what you're spraying? Mark said that his gun with a 1.3 would not spray #1 shellac, but why? What happens? too much or too little comes out?
The fact is, I'm a very scientific guy, and this topic is really intriguing my highest interest. I've got all sorts of sprayers. I've got a HF gravity hvlp 1.4mm, (3) HF LVHP old school bottom cup rigs, and I've got my Earlex 5500. I like the Earlex, but the thought of having a set air volume sort of bothers me. I use the 1.5mm nozzle set and I thin my lacquer 50/50. That's basically a 9% solids wash coat. I'd like to shoot it out of the can, but I get orange peel if I don't thin the hell out of it. Lucky for me, until now, all I shoot is nitro and precat lacquer. But, now I need to shoot this poly and I don't want to clean out the Earlex for the project, so I wanted to use my HF gravity gun(which I normally use to shoot NGR dyes) as it is a "clean" gun.
I feel like there's a huge puzzle piece missing from my understanding here.
Contributor
Mike, go to this link and download the PDF file: http://homesteadfinishingproducts.co...-pdf-document/ On page 2 you will see a chart labeled "Generic Chart and Nozzle Setups" which shows the viscosity range vs. needle size and gun type. Get yourself a cheap, plastic Ford #4 cup for $6 or $7 dollars and measure the viscosity of whatever you want to spray. That result will tell you what gun/needle will work and/or whether you have to thin the finish. I know nothing about the Earlex 5500, but looking at a picture of it shows a plastic hose connected from the gun to the paint cup. That suggests to me that it is an air assisted (pressurized) unit. If so, use the "Pressure Feed" column on the Generic Chart.
I don't think the GF guy really meant that his 1.3 mm needle gun wouldn't spray 1# shellac. What he probably meant to say was that it wouldn't be the best choice with an air assisted gun. My gravity feed HF gun with a 1.4 mm needle sprays 1# shellac beautifully. If the air assisted gun GF uses has adjustable air pressure, and it was turned down to zero, it likely would spray 1# shellac equally well. But optimally, he would want to use a needle around 1.0 mm or maybe even a little smaller with his air assisted gun.
John
Member
Mike, to directly answer your question, 1# shellac is very thin. It flows too readily for a 1.4mm setup.
My experience with the HF 1.4mm gun and 1# shellac is less positive than John's. Yes, it will spray it. Just not to my liking.
When I spray shellac it is usually tinted which really shows deficiencies in spray patterns. With the HF gun I need to crank up the pressure to get a fine and even atomization with the thin material and that results in massive clouds of overspray. Besides being wasteful, I'm not entirely comfortable with standing in a room full of highly atomized alcohol.
For that application, I use an Iwata LPH400-LV with a 1.2mm setup. I can get beautiful atomization at fairly low pressures. Plus, the gun is 2/3 the size and weight of the HF unit - very nice on the arm toward the end of long spray sessions.
Last edited by Mark Kornell; 04-17-2015 at 1:46 AM.
Member
I'm sorta with Mark K.......we're a Sata and Iwata shop here.
When it's all said and done,and we've left an incredibly long/expensive trail of cheap guns......and they do have their place,no denying that.But give me one of our premium guns and some "special",has to be perfect finish......they do make a difference.
As a data point,we're on the cusp of machining our own needle/cap sets.
[OP]
Member
You all have been very helpful! Well, I also ended up splurging on a new gun. I ordered one of Jeff Jewits(spelling?) Qualspray units. The Reduced pressure AM2012. I spoke with Jeff about it and I'm pretty excited to give it a go. He's an incredibly knowledgable guy. So, while not a $600 gun(holy smokes Mark!), I have high hopes for this rig. I'll be back here with a review after I use it a few times.
Member
I've read nothing but good things about the Qualspray guns and the advise that Jeff Jewitt gives, so I'm pretty sure you'll be very happy.
Posting Permissions
Reply With Quote