To spray, or not to spray...that is the question. (one of many!)

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Deeptree

New User
William
Again...we delve into finishing. I hate to beat several dead horses about this...but the choices of finish and the application methods available, provide roughly 128,000 (through repeatable permutations) options for finishing...and I am very confused, especially when it comes to spraying.

I have never sprayed before, but as I have several large pieces nearing completion and ready for finishing, I am thinking of spraying for the first time. I am very confused about the differences between traditional gravity fed/siphon sprayers, and the HVLP systems that I have been seeing people talk so much about. I understand that the traditional systems generally allow for a greater amount of wasted material, due to a much greater amount of overspray. Whereas the HVLP's pressurize the storage container and send the material out at a much slower velocity, providing less overspray with the same amount of material delivery.

I have heard good and bad about both, and read about the same. So here are a couple of questions that I would like to present, and get forum feedback.

Do differences in materials determine when you would use a traditional sprayer vs. an HVLP system?

I have several large compressors with filters...can I use them to power an HVLP system via regulators, or do I have to buy one of the turbine systems?

When spraying material, are there guidelines for the viscosity of the material?

If there are guidelines, where are they and how do you measure materials against these guidelines (please tell me that I don't have to just "get a feel" for it...because that means a lot of messed up wood! :nah: but...practice makes perfect I guess )
I am sure that these questions are rudimentary and simple, but I would really like to hear what others here are doing, because my next questions are regarding hardware recommendations for each type of sprayer. :gar-Bi
 

gfernandez

Gonzalo
Corporate Member
If you already have the compressor, it would be more economical for you to just buy a gun and learn how to use it. A good quality gun can be had much cheaper than an entire HVLP system, and when I had the same questions as you, almost all the experts out there, including Jeff Jewitt, recommended a gun over an HVLP system. Having said that, I am by no means an expert. But I am very picky and have been extremely happy with how my spray finishing turned out.

Here are some websites that may be helpful. I recommend calling and talking with them

http://www.spraygunworld.com/

http://www.paintsprayersplus.com/ (where I ultimately bought my gun. very helpful )

http://www.homesteadfinishingproducts.com/ run by Jeff Jewitt, guru of finishing
 

JimD

Jim
Senior User
I used to use a Wagner converstion gun - a HVLP gun which works off compressors. I had a lot of problems getting it set up properly, at least in part to my small compressor. When it worked, it worked fairly well. I thinned sometimes but still had difficulty getting it to spray properly.

I currently use a Fuji Mini Mite 3. I have been able to spray the water based finish I wanted without thinning. I have two cups and put water in one and finish in the other. I mess with the gun almost not at all. I just hook the finish cup up when ready to spray, spray until I am done (5-15 minutes and if it's 15 the quart cup will probably need refilled) and then spray water through it 3-4 times to clean it. Very good and dependable results. I put a cap on the finish cup and in a couple hours I pull the cap, put it on the gun and spray again. It's easy to put 4 coats on in a day.

When I used the wagner, I ran about 90 psi out of the tank and lowered it to around 20 psi with the regulator at the gun. That is one of many possible adjustments. I ran the high pressure from the tank to get the necessary air volume at the gun. Bigger hose would allow a lower tank pressure.

With a very high continuous cfm - say at least 7 cfm, preferably 10 or a bit more - and a GOOD HVLP gun made to work on compresssed air, I think using a compressor would work fine. But it requires an air pressure setting the compressor option does not. You also need a dryer on the air and if the compressor uses oil, you need to filter that too. It has to be a lot of clean dry air.

The turbine option simplifies the setup. It can make the setup nearly non-existant - once you get a setting you like. My experience with the compressor option, admittedly with too small a compressor on a low end gun, was a lot more frustrating at times. I was also amazed (a little) that my 3 stage turbine (there are 4 or more) would throw a nice 14 inch or so wide pattern. That goes through finish VERY quickly but if you need it, it is nice.

Gravity or siphon/pressure feed is an option for HVLP regardless of how you get it air. The Gravity gun looks like it gets into small spaces better. But it prevents the cup swapping I use to minimize cleanup time. The siphon/pressure option gives you a quart of finish and lets you swap cups. There are also pressure tanks that hold a lot more finish.

Jim
 

JWBWW

New User
John
If you are wanting to spray lacquers and dyes an HVLP conversion gun will suit you just fine. Starting from scratch with a turbine system may have its proponents... but I would be hard pressed to justify the expense if you have ample air of good quality. When I started experimenting with waterbornes I invested in a high end conversion gun... an Apollo. I have since sent it back to Apollo twice and each time they swear it's just great. In my opinion it is the biggest waste of $500 I have ever encountered. In disgust I returned to my standard set-up... a $49 Harbor Freight copy of a successful Devilbiss conventional gun with 2 quart pressure pot. A few years passed and I tried a Porter Cable gravity feed HVLP gun... ugh. Another highly recommended HVLP conversion gun copy of some unknown make was tried and set aside. My last attempt was a Lynx 3 HVLP conversion gun from Hood Finishing... for under $130. (http://www.hoodfinishing.com/Products_info/LYNX_Spray_Gun.pdf). I have had nothing but good results with this gun connected to a 2 quart pressure pot which remains my preferred setup.

Because we tend to revert to what works the way we are used to... I tend to spray large jobs with my trusted old high pressure Harbor Freight rip off. It still delivers a great finish after something close to 150 gallons of material running through it and countless kitchens and bathrooms and wall systems sprayed. But with the increasing cost of finishing materials and concerns for air quality it's probably time to fully convert to the HVLP setup. You'll want to spray and fiddle around with your viscosity until you are happy. Get a Zahn cup (or similar) and test each and every pot of material until you've hit on what works for you. Then you'll know pretty much everything you need to know about what works best in your gun and your spraying style. Some folks tend to move their gun faster and keep their gun farther from the workpiece... all of which is to say that there really aren't many hard and fast rules. I got tired of waiting thirty seconds for material to flow through an old plastic DuPont viscosity cup so I drilled it out with a 3/16 bit. Now I know that any material needs to be about 13 seconds through the cup to flow out best. Like I said... make a set of rules that work for your own setup. And spend a lot of time with practice. This isn't any different than hand cutting dovetails or shaping a cabriole leg... all it takes is determination and practice.

If you are anything like me, you will become so happy with spraying finishes that you will find it difficult to go back to brushes and rags. NC lacquer is perhaps the most forgiving finish of all: fast, easy to apply, and gorgeous results almost every time. Yes, humidity is not our friend. But good retarders have made this a manageable problem. Sure there are times when a surface finish isn't called for. But for most of the work that I do nowadays, lacquer in one of its forms is where I tend to be.

As I think about the obsession of folks about buying the best/most expensive gun out there I am reminded of a story my son, a guitarist, passed on to me...

Chet Atkins was in a Nashville studio warming up for a session with his Gretsch. A young technician came into the studio and stood watching open-mouthed until Chet finished. ”Gee, Mr Atkins, that guitar sure sounds fabulous!” Chet placed the guitar on its stand, smiled at the tech and said, “Well, son, how does it sound now?”
 

Deeptree

New User
William
If you are wanting to spray lacquers and dyes an HVLP conversion gun will suit you just fine. Starting from scratch with a turbine system may have its proponents... but I would be hard pressed to justify the expense if you have ample air of good quality. When I started experimenting with waterbornes I invested in a high end conversion gun... an Apollo. I have since sent it back to Apollo twice and each time they swear it's just great. In my opinion it is the biggest waste of $500 I have ever encountered. In disgust I returned to my standard set-up... a $49 Harbor Freight copy of a successful Devilbiss conventional gun with 2 quart pressure pot. A few years passed and I tried a Porter Cable gravity feed HVLP gun... ugh. Another highly recommended HVLP conversion gun copy of some unknown make was tried and set aside. My last attempt was a Lynx 3 HVLP conversion gun from Hood Finishing... for under $130. (http://www.hoodfinishing.com/Products_info/LYNX_Spray_Gun.pdf). I have had nothing but good results with this gun connected to a 2 quart pressure pot which remains my preferred setup.

Because we tend to revert to what works the way we are used to... I tend to spray large jobs with my trusted old high pressure Harbor Freight rip off. It still delivers a great finish after something close to 150 gallons of material running through it and countless kitchens and bathrooms and wall systems sprayed. But with the increasing cost of finishing materials and concerns for air quality it's probably time to fully convert to the HVLP setup. You'll want to spray and fiddle around with your viscosity until you are happy. Get a Zahn cup (or similar) and test each and every pot of material until you've hit on what works for you. Then you'll know pretty much everything you need to know about what works best in your gun and your spraying style. Some folks tend to move their gun faster and keep their gun farther from the workpiece... all of which is to say that there really aren't many hard and fast rules. I got tired of waiting thirty seconds for material to flow through an old plastic DuPont viscosity cup so I drilled it out with a 3/16 bit. Now I know that any material needs to be about 13 seconds through the cup to flow out best. Like I said... make a set of rules that work for your own setup. And spend a lot of time with practice. This isn't any different than hand cutting dovetails or shaping a cabriole leg... all it takes is determination and practice.

If you are anything like me, you will become so happy with spraying finishes that you will find it difficult to go back to brushes and rags. NC lacquer is perhaps the most forgiving finish of all: fast, easy to apply, and gorgeous results almost every time. Yes, humidity is not our friend. But good retarders have made this a manageable problem. Sure there are times when a surface finish isn't called for. But for most of the work that I do nowadays, lacquer in one of its forms is where I tend to be.

As I think about the obsession of folks about buying the best/most expensive gun out there I am reminded of a story my son, a guitarist, passed on to me...

Chet Atkins was in a Nashville studio warming up for a session with his Gretsch. A young technician came into the studio and stood watching open-mouthed until Chet finished. ”Gee, Mr Atkins, that guitar sure sounds fabulous!” Chet placed the guitar on its stand, smiled at the tech and said, “Well, son, how does it sound now?”

John & Jim;

Wow...what an amazing response! Thank you VERY VERY much! This is a lot of information to take in and the bottom line seems to be:

  • Both high-pressure and HVLP systems have merits.
  • HVLP has merits that I may not be able to realize with my lack of experience and exposure.
  • High pressure systems are low-cost, allow me to start quickly and cheaply, and work my way up.
  • Either method is going to require a GREAT amount of practice, patience and generated scrap wood that I can't burn in my fireplace. :gar-La;
  • I need to spend time doing mixes of different materials and shooting them to get a better feel for how they lay down, what they do to the guns and what my outcome will be.
I welcome ANY other input here, especially what materials are good to spray, and which aren't. So do lacquers spray good, and stains don't? Do stains spray well and varnish doesn't?
 

JWBWW

New User
John
Just up from the shop and read Jim's post. Not sure what to make of the notion of running 90 psi into a gun of any variety that I have tried... but if it works that's what this string is about. The most pressure I have had going to any pressure pot and gun is 35psi and more usually 28 does a beautiful job with either the HVLP conversion gun or the conventional high pressure gun (both fall within manufacturers specs). Pot pressure is always between 8 and 10 psi. While many will advertise that a compressor of x horsepower will do the job... it's best as Jim points out to have minimally 7 continuous cfm available. In most cases this is a 65 or greater tank size and larger pump than most diy machines.

I have pretty well plumbed pipe layout (all 3/4 schedule 40 with drains at every drop) and at the spray station end of things I have a reasonable filter/regulator (although it's never seen a drop of water in eleven years). Never had a dryer nor have I ever had an oil contaminant problem which is usually manifested in pinhole fisheye in the finish. But I should add that I should never say never... there's a long way to go before sundown.
 

JWBWW

New User
John
In my experience spraying stain is a phenomenal waste of time and material and ultimately money. Since stain requires wiping down most of what comes out of the gun that doesn't hit the floor ends up on a rag that eventually gets thrown out. And then there is that mess all over the shop floor. Pigment stains are best ragged or brushed on. Varnishes are moderately okay to spray but the downside is that drying time still makes this a less than satisfying experience... not to mention the mess of cleanup. Nitrocellulose lacquers are the perfect spray finish. By the time overspray hits the shop floor it's dust that can be swept up. With fast flash and dry time a wet coat can be sanded in 20 to 30 minutes and a four step finish applied to a reasonable sized project (42" x 96" dining room table) in four to six hours.

Dye stains are also wonderful to spray but a little trickier as they flash off so quickly one has to hold in memory what it looked like wet. When topcoats are applied all the color comes back and it's possible to be very surprised by one's own generosity of color. Conversion varnish is another great finish for spraying although I have never had any luck mastering this steep learning curve. One finish shop that I use for paint uses nothing but conversion varnish and has fantastic results. I have had mixed results with waterbornes and will continue t pursue this technology that seems to change at least once a year. Finishes get better each year in this category and eventually we'll all be using them whether we like them or not.

I would suggest that if you set out on your own to spray finishes you will learn a lot very quickly and have some fun and frustration along the way. I will also say that if you spend a few hours anywhere spraying is being done you can master a fantastic finish in a few hours. Best advice is to get your hands on Andy Charron's Taunton book "Spray Finishing"

http://www.amazon.com/Spray-Finishi...1143/ref=sr_1_1?ie=UTF8&qid=1323727866&sr=8-1
 

junquecol

Bruce
Senior User
My experience is limited to three guns, Devilbiss siphon pot, Apollo HVLP, and HF HVLP gravity feed gun. The Devilbiss wasted a lot more of the finish than it applied to surface. I had to spray outdoors and with the wind to my back. Without a wind, there was a FOG of $50 a gallon water based poly. Bought an Apollo gun (built my own turbine), and paid for it in two jobs on WB poly ($50 a gallon) saved. With the Apollo, I can spray the inside of a coffee cup. Bought HF gravity guns to spray handrails, and have been very pleased so far. When I bought guns, I paid either $9.99, or less than $12. I consider these HF guns to truly be a HF Gem. When I clean then in the afternoon, I spend more labor (time = $$) and mineral spirits than either of the guns cost. I bought the disposable cups, but still have to take gun apart to clean the filter, so I just run the original cup. The HF guns will be $9.99 on the weekend of January 13,14,& 15. I run my HF gun off a twin stack Devilbiss compressor. Sometimes I have to let compressor catch up, but not often.
 

JimD

Jim
Senior User
My favorite finish is Resisthane. It is a water based poly that has some characteristics of a pre-cat lacquer. You do not have to sand between coats, for instance, because each coat disolves a little of the previous. It can also be brushed. About $40/gallon delivered to my house. I got impatient and am trying a gallon of General finishes water based poly. It will probably be the last. Finish seems to build incredibly slowly compared to resisthane.

I've used conventional guns a little too. I agree they work but I don't see the point. HVLP guns are not expensive and they don't waste finish or force you to deal with all the fumes. Even water based will stink things up. The primary advantage I see in water based is ease of cleanup. That is a big advantage to me. They also dry quickly like a conventional lacquer.

It is realitively easy to spray a horizontal surface. It is relatively difficult to lay a nice wet coat on a vertical surface without sags and runs. I generally aim to be a little dry on vertical surface. Good lighting lets you see where you are at as you go.

With solid wood projects, you can sand off mistakes relatively quickly. I do my share of sanding finish off. I do not like to stain and one disadvantage is that you will go through the stain trying to get sags and runs off. Starting out, I would dye if I had to add color or just let the natural color of the wood show (my favorite).

Jim
 

Jeff

New User
Jeff
You might be interested in the Earlex 5500. About $320 at Amazon. It's only a 2-stage turbine, but far cheaper than a Fuji so you can experiment without having a second mortgage.

http://www.earlex.com/hv5500.php

The 1.0 or 1.5 mm spray tip is recommended for low viscosity liquids like dye (in water or alcohol) and shellac (a 1 lb. cut in alcohol works nicely). Latex paint needs the 2.0 mm tip because of the higher viscosity. Practice, practice, practice, and practice some more on horizontal and vertical scraps until you feel comfortable with the spray pattern and volume. It's not really hard, but there is a learning curve.

A good commentary and video by Marc Spagnuolo.

http://thewoodwhisperer.com/episode-45-music-to-my-earlex/
 

Howard Acheson

New User
Howard
>>>> I am thinking of spraying for the first time.

Never, NEVER let a real project be your learning curve with any finish process. This is particularly true with spraying. Proper spraying is a process that must be learned and practised. It's not something where you just fill up the gun and pull the trigger. In my shop, apprentice finishers spent a week or two being taught and practicing before they were allowed to do anything real.

First, get a book like the one by Charron titled Spray Finishing. It will tell you what equipment you need, how to set it up and how to use it. It will tell you the adjustments available to shape and control the spray pattern. It will tell you how to "read" the spray pattern to know what control needs to be changed. It will tell you the mechanics and technique of how to spray.

The final step is to practice on scrap, or even better, cardboard boxes until you learn how to get the results you are looking for.
 

Jeff

New User
Jeff
Absolutely excellent advice from Howard A. However, there is a catch and its called "analysis to paralysis". No substitute for rolling up your sleeves, get some practice, and go for it.

Refrigerator or freezer boxes are available from a local home appliance store and they're good for practice. They also make a convenient backdrop for containing the overspray. :icon_cheers
 

JWBWW

New User
John
Not sure where this all leads other than to submit my final two cents.

Yes... spray a bunch of sample pieces and look at what you have done and think about what you have learned. But if the work you are doing is for yourself then do it however you think works best for you. I wish I were geographically closer so that I could contribute all the plywood scraps you need to have a spray fest for a few hours. But I'm not certain anything is going to be like spraying the actual work... your actual project. In my experience the real thing is where problems arise and, more importantly, where they get solved. We never look terribly closely at our practice work, do we? I know that in the color and sheen samples I submitted for approval on a pair of end tables two weeks ago I never noticed the sanding scratches left from the hired-out widebelt work done because I had bad knives in my planer and an itchy customer (forget that I spent six hours sanding from 100 through 220 with a RO). When I applied the three dyes and then topcoats it all came clear to me... so to speak. We learn to adapt when we make errors in our finished work... not when we spray expensive finishes on cardboard boxes. I mean not to take anything away from the outstanding advice given here... but to temper it with some humility and a little reality. "Perfect" really can get us hung up. The reality is that there is nothing that can't be remedied and there is nothing like the experience of "just doing it." If it were transplant surgery it would be different. But it's just finish and an inanimate object on it's way to becoming more beautiful
 

JimD

Jim
Senior User
I agree with John, the post above. I do not have the patience to spray a bunch of finish on cardboard. I spray water on boxes to test the pattern sometimes. But then I have to waste some finish to clear the water out. I usually just leave the Fuji set up and trust it will spray like it did when I put it away. I would avoid staining and plan to sand some finish off when you goof up and just start. Orient your pieces horizontal as much as possible but just practice by doing.

With respect to the cost of the Fuji, I thought I was saving money buying the Wagner I used to use. In reality it would have been cheaper to buy the Fuji from the start. If you want to try a $20 HF gun to see how you like it that makes sense to me. Maybe an Earlex wouldn't end up getting replaced eventually but I am confident the Fuji is better - and about $200 more. Nice tools are nice to use. The Fuji is nice, and much less than any other professional system. It's also the cheapest system that tests I have seen say will spray typical unthinned poly. Thinning finish just makes you have to spray more coats and have more problem with runs.

Jim
 

Deeptree

New User
William
I agree with John, the post above. I do not have the patience to spray a bunch of finish on cardboard. I spray water on boxes to test the pattern sometimes. But then I have to waste some finish to clear the water out. I usually just leave the Fuji set up and trust it will spray like it did when I put it away. I would avoid staining and plan to sand some finish off when you goof up and just start. Orient your pieces horizontal as much as possible but just practice by doing.

With respect to the cost of the Fuji, I thought I was saving money buying the Wagner I used to use. In reality it would have been cheaper to buy the Fuji from the start. If you want to try a $20 HF gun to see how you like it that makes sense to me. Maybe an Earlex wouldn't end up getting replaced eventually but I am confident the Fuji is better - and about $200 more. Nice tools are nice to use. The Fuji is nice, and much less than any other professional system. It's also the cheapest system that tests I have seen say will spray typical unthinned poly. Thinning finish just makes you have to spray more coats and have more problem with runs.

Jim

Jim & John;

I want to thank both of you very much. Your input has really had me off reading and talking to people over the last couple of days. I purchased several books, including the one by Jeff, and it was really funny that the first chapter was titled "To Spray or Not To Spray"...had I known that, I wouldn't have named this thread that. :)

So, with everything that people here have said, along with the input that I received from some other folks, and the portion of Jeff's book that indicated that (paraphrased) "HP guns waste approximately 75% of the material" this seems to be my plan of action, and I would like any input from those experienced to tell me if this seems logical:


  1. Purchase an HF gun that will give me the ability to practice with water, and some other cheap water-based solutions, which I can play with viscosity and technique, without breaking the bank and trashing some good future scrap. :)
  2. Purchase an HVLP hybrid gun (the one with the regulator attached to the inlet fitting), and again practice with the same water and water-based materials, focusing on spray patterns and dispersal size, seeing how it lays down with larger globules.
  3. Once I am comfortable attempting to stain a real peice of work, purchase either an Apollo or a Fuji (although I am leaning toward the Fuji, because of reviews and feedback) 4-stage system, and go to town. This is the most expensive option, ranging from $500 - $1400, depending on which route I go, and I want to make 100% sure that this will work for me and last me for the next 10 years.
Thoughts? Suggestions? Should I not spend a dime until I go and take a spray class somewhere?
 

JWBWW

New User
John
There are no more expensive finishes than waterborne ones. Period. Forget that they bear no resemblance to solvent based lacquers and varnishes in their feel and their application. They are harder to spray and even harder to pay for. Yes... an HVLP system will deliver more finish to the substrate... but the cost for the infrequent user is steep for the equipment. I finished a pair of custom designed and built end table yesterday for my best customer... natural khaya with oiled western quilted maple tops using my $49 Harbor Freight high pressure gun. I left well over $2000 in guns and pressure pots hanging from the ceiling one more time. I would consider the acquisition of a low cost gun your absolute best first step. Try to get one that has all stainless innards so that if you absolutely must spray waterbornes you won't ruin the gun outright.

Send me a PM if you want to discuss any or all options. I'm no expert... just a fellow with some experience building the scrap pile. I still recommend Andy Charron's book and use it routinely to troubleshoot. Consider that all we have managed to write about is how to do it right. There's way more to fixing it when it goes wring. Blush in itself is a chapter in any southern woodworker's book.

John
 

Deeptree

New User
William
I still recommend Andy Charron's book and use it routinely to troubleshoot.

John

John...thank you again. I tried to find this book on Amazon, but it appears to be out of print and not available directly from Amazon, only through 3rd party distributors. I will find a trusted one and go from there.

William
 

Robb Parker

Robb
Corporate Member
William,
I started to input my .02 cents worth here but decided against it. I have been finishing cabinets and furniture for 35+ years (level 7 coatings and spray technologies certified) and the evolution in spray technology and materials is beyond believe both in equipment and materials. Particularly in the last 10 years as a result of governmental regulations of VOC's. I think for the most part, the information you have been given is sound and agree with some. However, some of the information I strongly dissagree with. I don't want to start a flame war or debate here. Finishing is indeed part science/chemistry, part art. If you don't have the basic science right, your art will surely fail!

Finishing, like most woodworking, takes an investment, both in money and time. Your being in Gastonia, fairly close to me, I offer you to come to my shop and try out spraying. I have a Colmet spray booth, Sata convential and HVLP gravity guns, touch up and glazing guns and CA Technologies AAA system on the equipment side. Pre cat and post cat conversion varnishes, nitrocellous lacquer, sanding sealers, vinyl sealers, clears and pigmented, dye stains, sprayable wiping stains etc, etc on the material side. I do not finish with water bourne so you'll have to bring your flavor of that. (I have experimented with it just science not there yet for me. Another debate!)My equipment will spray it though and set up will be close to same as with solvent finishes.

If you intend to spray finish, you will need to find a supplier. You won't find any finishes at the BORG or the supplies needed. All that said, once you started to spray finishes, you'll likely, as said in this thread, not go back to rags and brushes. Don't let anything said (by me or others) scare you away from fine finishes spraying. With practice and some knowledge, you can get some very beautiful finishes!

Call me anytime to arrange if you want. I have plenty of cardboard and scraps.Offer is for anyone.

Robb Parker
Heritage Woodwright llc
3670 West Bay Dr
Sherrills Ford, NC 28673
828-228-8072
 

JWBWW

New User
John
I cannot imagine any better offer than Robb Parker's here. Not only the experience to guide... but a proper spray booth in which to test your learning curve without risk to self. I am also in complete agreement that once you spray you will never want to come back.

Robb... when you have mastered spraying waterbornes please post some kind of heads up so that I can come and watch you spray a job.

John
 
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