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Does anyone use HVLP gravity feed to spray finish?

Spud

Diamond
Joined
Jan 12, 2006
Location
Brookfield, Wisconsin
Since I am in tech college's automotive program, part of which involves the entire painting process, I have a Sata gravity feed HVLP spray gun. The pressure at the tip is 10 psi. The inlet pressure is around 29psi. We use only gravity feed cups.

I am wondering if commercial / profession wood finishers use HVLP for spraying Polyurethane or Conversion varnish? Or are these finishes almost now mostly sprayed with Airless or Air Assisted sprayers, such as those by Graco and Kremlin? The cabinet making program at school is just setting up a new Kremlin system ; not sure on the model #. They have more or less moved away from the pressure-pot system.

Is there any downsides to spraying with a high quality HVLP like the Sata guns? Cleaning of the gun wouldn't be an issue, because I am used to fastidiously cleaning it with copious amounts of lacquer thinner in-between spraying Primer, Sealer, Basecoat and Clear Coat (for automotive painting)

This my gravity feed HVLP gun.
sata-4000b-digital.jpg
 
I can't answer your question, but you might want to ask on this forum, lots of pros there
WOODWEB's Finishing Forum - Message Index

That SATA is a nice gun, I use several of their minijet guns to spray nitrocellulose on my banjos. I'd like to switch from gravity to pressure feed tho, I find the cup awkward for spraying rims, would like to be able to spray from any position. Thinking to make an adapter to convert one.
 
I have a gun like yours without the digital gauge and a mini-jet. They are great machines.

I have been at George Krenov's school and at Sam Maloof's workshop. No sign of spray equipment. Things might have changed since then. I would rather use a Tung Oil / Varnish / Bees Wax mix like Maloof. Spraying is not for the fine furniture.
 
I have a gun like yours without the digital gauge and a mini-jet. They are great machines.

I have been at George Krenov's school and at Sam Maloof's workshop. No sign of spray equipment. Things might have changed since then. I would rather use a Tung Oil / Varnish / Bees Wax mix like Maloof. Spraying is not for the fine furniture.

Plenty of fine furniture is finished by spraying. Looking at Maloof and Krenov is a very narrow view of the fine furniture movement. The majority of makers I know, and this is not a small sample, spray their work (including me). It is almost expected by clientele to have a sprayed piece at this point. I agree that there is still a sector of work that is not sprayed, but it is certainly an appropriate finishing technique.

Pete
 
Plenty of fine furniture is finished by spraying. Looking at Maloof and Krenov is a very narrow view of the fine furniture movement. The majority of makers I know, and this is not a small sample, spray their work (including me). It is almost expected by clientele to have a sprayed piece at this point. I agree that there is still a sector of work that is not sprayed, but it is certainly an appropriate finishing technique.

Pete

Most have their own definition of "fine". They would not know the difference between a hand rubbed finish and a spray can coat of Deft.
 
I have a gun like yours without the digital gauge and a mini-jet. They are great machines.

I have been at George Krenov's school and at Sam Maloof's workshop. No sign of spray equipment. Things might have changed since then. I would rather use a Tung Oil / Varnish / Bees Wax mix like Maloof. Spraying is not for the fine furniture.

I have to disagree here. I knew both Sam and Jim quite well, and while I liked them and their work, I never thought it was particularly fine or sophisticated. My idea of fine furniture is the french art deco stuff, especially Ruhlmann. Maybe not to your taste, but unquestionably fine, and incredibly expensive, and sprayed with nitro cellulose lacquer. Oil finishes are lovely, but offer very little protection and require a lot of upkeep. Not very practical for a dining room table. I think they are popular with hobby and studio furniture makers because they are easy to apply and require no special equipment.
 
I have to disagree here. I knew both Sam and Jim quite well, and while I liked them and their work, I never thought it was particularly fine or sophisticated. My idea of fine furniture is the french art deco stuff, especially Ruhlmann. Maybe not to your taste, but unquestionably fine, and incredibly expensive, and sprayed with nitro cellulose lacquer. Oil finishes are lovely, but offer very little protection and require a lot of upkeep. Not very practical for a dining room table. I think they are popular with hobby and studio furniture makers because they are easy to apply and require no special equipment.

I built my dining room table in 1990. It has a hand rubbed finish. I'm not sure what you mean by "upkeep" besides periodic dusting. I have done a few touch-ups for scratches without moving the table to a spray booth. The negative on that is the strong smell. The biggest negative is the length of time it takes. To build up the thickness to semi-gloss can take more than 7 applications. More than a week and then dealing with the smell.

The only things I would spray nitro on are my guitars.

The order of finishing methods from "Fine" to "Coarse".
1. French polishing.
2. Hand rubbed. Like french but no bag of pumice is used. Intermittent rubs with steel wool can be used.
3. Spray.
4. Brush.

1 and 2 also allow for a range of textures. From dull, to matte, semi-gloss, gloss.
Any higher reflective category then you might as well consider getting plastic furniture.

I can see your point about spraying. But I think you are wrong about a guy like Krenov. Handwork to the extreme with a lot of scraping, no sanding methods used.
For Maloof's work like a $10,000 rocking chair there is a lot of sanding done and maybe the work would not be considered fine enough.
 
Rons, understand that Richard is in another league when it comes to fine furniture- above Krenov and Maloof and known for it. Arguing with him that fine furniture isn't sprayed is just plain silly.

Back to the original questions. Spud, yes, I use a HVLP gun to spray conversion varnish with. I have a couple and have had good success through the years. I'd say the biggest downside would be making sure you have a clean and dry supply of air.

Pete
 
Rons, understand that Richard is in another league when it comes to fine furniture- above Krenov and Maloof and known for it. Arguing with him that fine furniture isn't sprayed is just plain silly.

Back to the original questions. Spud, yes, I use a HVLP gun to spray conversion varnish with. I have a couple and have had good success through the years. I'd say the biggest downside would be making sure you have a clean and dry supply of air.

Pete

Custom furniture makers, making high end stuff, what spray method are they primarily using, HVLP or Airless/Air Assisted Airless?

Is there any advantage to use Airless / Air Assisted over gravity feed HVLP, other than spraying at awkward angles and spraying large areas such that using a gravity feed HVLP would require many refils of the cups? But if spraying large areas, then one could use a pressure pot HVLP system.

As far as a top notch finish goes, what spraying system would the pros use to spray wood window and door frames / trim?
 
I use an Accuspray (now 3M owned) HVLP cup gun that I got a long time ago. It works very well for me, only downside is it takes too long to clean properly. At the old job we used quite a few gravity feed guns but also had a Kremlin airless that was used on larger jobs. That is what I see in this area, a combo of gravity feed for smaller jobs but they are mostly using a Kremlin. They are spraying any number of products through them as well. Downside to those is the 23 oz of product to get out of the lines to clean it.

If it is a truly custom furniture shop, I would guess the jobs are small enough to just use gravity feed guns as I don't think the volume would justify the expense to clean up a Kremlin type setup.

At my shop all of my personal and customer work gets precat laquer as I like the results and have the most experience with it and I can get it locally.

At the old job we did quite a few commercial millwork jobs that were considered high end that had post catalyzed laquer for finish on them. While above average quality, I would have to defer to others as to what is used on fine furniture.
 
I'm a cabinetmaker (mainly kitchen and custom furniture) and have been at it for 40 years. For my work, I use a post-cat varnish for the most durability and chemical resistance. I started out with Binks equipment and switched over to gravity HVLP 10 years ago. I had a nice CAP gun, and picked up a DeVilbiss Finishline for use in spraying stains. However, the Finishline became my favorite gun and I use it for all my topcoats.

Jack
Fort Loramie, Ohio
 
Rons, understand that Richard is in another league when it comes to fine furniture- above Krenov and Maloof and known for it. Arguing with him that fine furniture isn't sprayed is just plain silly.

Back to the original questions. Spud, yes, I use a HVLP gun to spray conversion varnish with. I have a couple and have had good success through the years. I'd say the biggest downside would be making sure you have a clean and dry supply of air.

Pete

There is no argument. My points are:

- Dr. Devilbiss and Joseph Binks came up with spray gun technology in the 1800's. What did furniture makers use before that? LOL
- Just because furniture is modern does not mean that it is fine.
 
Custom furniture makers, making high end stuff, what spray method are they primarily using, HVLP or Airless/Air Assisted Airless?

Is there any advantage to use Airless / Air Assisted over gravity feed HVLP, other than spraying at awkward angles and spraying large areas such that using a gravity feed HVLP would require many refils of the cups? But if spraying large areas, then one could use a pressure pot HVLP system.

As far as a top notch finish goes, what spraying system would the pros use to spray wood window and door frames / trim?

Have you seen the size of the cup that is sold with your spray gun? It's huge. Your arm will drop off from fatigue before anything else.
 
There are a few downsides to a gravity feed gun. The weight of it full is just one, next is the limitation of the spray angle. No spraying the underside of a cabinet interior, you must flip the cabinet over. The atomization on a pressure pot is better than a gravity feed, air assisted is even better than a pressure pot. Better atomization equals better finish. Cleaning is not a big issue they all have to be cleaned.

There are some upsides like fast to set up and quick to change finishes. Great for small jobs done occasionally, for larger jobs not so good.
The best finishes I have seen are from air assisted airless systems, I have not owned or used one but know lots of shops that do and one local shop has done some work for me over the years. I currently own a pressure pot but have not sprayed anything in four or five years. Going from gravity to pressure is like going from hand drilling to a power feed drill press, you will not want to go back.
 
I have to agree with that.
I push most things through the Binks 2qt pot except the smallest jobs.
For detail out of position work on even small jobs it’s nice to work from the pot.

Who’s to say you have only one.
I have pots, siphon, gravity and turbine setups in the shop.
Just pick the one that suits the work..

The one thing I don’t have is high pressure airless.
I was going that route years ago when I was taking contracts spraying spars with AwlGrip in such a small tube tent that I couldn’t see the work for all the overspray in the air.
Thankfully I lost the contract eventually and before I cashed out for the gear.
 
I have a Graco HVLP outfit that is good for bigger projects like doors, house trim and multiple cabinets at once. It uses a can under the gun. Then I have a small Sata HVLP that is gravity fed. Its really handy for furniture and smaller things (like readily picked up by one person). Then I have and really like a small Pasche conventional sprayer that uses a glass bottle. Its kind of an oversize airbrush. Very useful and quick to set up and clean up. Finally, a Pasche airbrush for small things.
 
There are a few downsides to a gravity feed gun. The weight of it full is just one, next is the limitation of the spray angle. No spraying the underside of a cabinet interior, you must flip the cabinet over. The atomization on a pressure pot is better than a gravity feed, air assisted is even better than a pressure pot. Better atomization equals better finish. Cleaning is not a big issue they all have to be cleaned.

There are some upsides like fast to set up and quick to change finishes. Great for small jobs done occasionally, for larger jobs not so good.
The best finishes I have seen are from air assisted airless systems, I have not owned or used one but know lots of shops that do and one local shop has done some work for me over the years. I currently own a pressure pot but have not sprayed anything in four or five years. Going from gravity to pressure is like going from hand drilling to a power feed drill press, you will not want to go back.

Here is where I am confused : incoming pressure for gravity-feed HVLP and pressure pot HVLP is under 40psi, whereas Airless can be upto around 3000psi, and air-assisted airless over 1000psi. So these are 2 very different systems, yet both can provide similar high quality finish spraying?

In the automotive world, no one uses airless or air-assisted airless, it is all HVLP or the newer technology like Sata's Reduced Pressure guns which is very similar to HVLP but works on lower pressure.
 
What do the auto manufacturers use?

Been googling , and surprisingly it is info that is not readily available.

The closest to an answer is from below Yaskawa robotics website that mentions their automotive paint robots can utilize HVLP or Airless / air-assisted airless.
Painting & Dispensing - Yaskawa Motoman Robotics

Here is a Ferrari video of their production ; skip to 3:40 and 4:41.
In addition to robots, paint is also applied manually, but I can't tell if it is some kind of specialized HVLP system or airless / air-assisted airless.
YouTube

Here is a German company that manufacturers and installs paint spray lines for the automakers, but no mention in their website of what system it is, other than utilizing electrostatic adhesion.
Portfolio for Passenger Car Manufacturing | Durr

I guess I should have clarified in my previous post I had in mind the aftermarket paint industry.
 
Yes, I googled also and came up empty handed. I understood your comment, but it made me wonder what the big boys do. My guess would be some sort of airless / air-assist. That seems to be very common in the furniture industry also.
 








 
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