HVLP Turbospray Technology, Figuring Out the Facts
Last month I was writing to you from my hotel room in Houston, TX on my way to Mexico and then Birmingham, AL. I was sharing my experience in meeting with diverse customers from serious home woodworkers to new industrial distributors. My comments to you were focused on the most common questions we are asked about HVLP Turbospray Technology. I talked about customer concerns regarding cleaning a spray gun to adjusting coating viscosity. If you didn’t get a chance to read my last comments you can go to www.thefinishingstore.com and read Newsletter #141.
Since my last writing my travels continue. I’ve visited Woodcraft stores in Nashville, TN, Woburn, MA and Walpole, MA, meeting with staff and customers to share product knowledge and information. This month I’m writing to you from Las Vegas and the SEMA Automotive Show, where once again Apollo HVLP Turbospray is being exhibited, this time to the vast automotive marketplace. We're presenting the benefits of our products and technology to the automotive finisher.
Interestingly many of the same questions continue to come up. As I promised at the end of last month’s writing, I will continue with another question that is frequently asked.
“What does 2 stage, 3 stage, 4 stage, 5 stage mean, and how do I select the right equipment for my application?”
Let me try to put this all into perspective for you.
- Turbospray motors are impeller or fan driven. Each motor stage refers to how many fan blades are producing the air volume. For example, a 2 stage turbine or impeller motor has two fan blades. 3 stage, three fan blades, etc. all the way to 5 stage and five fan blades.
- As the motors increase in stages, power output or maximum atomizing pressure increases.
- What you are purchasing is a power or maximum pressure level.
Another common question asked:
“I will use my Turbospray system infrequently or on small projects, so what is the smallest or least expensive system I can purchase?”
- You cannot look at Turbospray Technology based on frequency of use or the size of the project but rather the question to ask is: What coatings or finishes do you intend to use with your Turbospray system?
- If your answer limits your coating choice to very thin or low viscosity finishes and nothing more, then a lower powered system will probably satisfy your needs.
- As your requirements increase (pigmented coatings, coatings that need to be applied at higher viscosities, harder to atomize coatings, or coatings that limit how much you can thin or lower viscosity) then a higher output turbine is necessary to produce the desired results.
- Trying to apply a coating at a recommended viscosity with an underpowered turbine for that product will simply produce frustration and disappointing results. I guess it boils down to “the right tool for the right job.” Asking a few questions generally leads to a satisfactory purchase and a rewarding spray finish experience.
One last thought on this subject of Turbospray power (atomizing pressure). All Turbospray motors are not equal in power/pressure.
- There are 2 stage Turbospray motors that output a maximum of 3.5psi and others that provide 4.5psi.
- There are 3 stage Turbospray motors that output 5.5psi and others that provide 7.0psi. (Apollo ECO Series and Apollo Power and Precision Series).
- There are 4 stage motors that output 7.0psi and others that provide 9.0psi. (Apollo ECO Series and Apollo Power and Precision Series). You get the idea now.
- The higher the available pressure, the easier it is to spray today’s modern coatings and finishes that are either higher in viscosity or that limit the amount of thinning to provide both environmental compliance and product integrity.
I’m not trying to scare you away from lower pressure units but rather want you to ask yourself the question as to what coatings and finishes you intend to spray. As we continue to test products as part of our Research and Development, I will continue to share our findings with you in future comments.
The questions keep coming and I will continue to share the questions and answers with you. In future comments I will address nozzle, needle and air cap selection, bleeder and non-bleeder style HVLP spray guns and limitations of low cost HVLP.
Right now, it’s time to get back to the exhibit booth and meet with attendees to answer their questions on the benefits of HVLP Turbospray Technology for the automotive marketplace.
Between now and my next writing in December, I will have been in Washington, DC, Minneapolis, MN and Austin, TX. My next article will come to you from the Apollo factory in Vista, CA. I’m sure by that time there will be more questions! In fact if you have a question on HVLP Turbo Technology that I can answer for you, please send it to me directly at email@example.com
Happy Thanksgiving to all our customers.
Sr. Vice President, Sales & Marketing
Apollo Sprayers International, Inc.
Breaking News! ECO-Series HVLP Systems Score High on Popular Woodworking "Tool Test"
"It’s a great setup to allow woodworkers to explore and use HVLP technology at a reasonable price."
We were delighted to see that Popular Woodworking had a highly favorable response to the new ECO-Series 3, 4 and 5-stage HVLP Turbine Systems. They have a reputation for being picky about the products they recommend. This is just some of what they had to say in their November, 2013 issue:
"The name ASI-HVLP may be new to you, but when you discover that the company behind this new brand is, in fact, Apollo Sprayers (which is credited with bringing HVLP to the amateur woodworker market) all questions are answered.
The Eco series – designed specifically for small shops and do-it-yourselfers – is a range of portable turbine spray systems that provide premium finishing performance at an affordable price." READ MORE
Copyright 2013, POPULAR WOODWORKING
Charles Neil's NEW Finishing Book Preview Tip: Avoiding Dye Migration
Editor's Note: In the next couple of months we will all be able to see Charles Neil's new and definitive book on finishing: Charles Neil: Finishing Simply Put: Chemistry Degree Not Required. You are lucky enough to get a sneak preview with this tip:
The general consensus on dying figured woods is pretty much saturation, or using a trace coat to further intensify the grain. However sometimes a dye can migrate, meaning it just goes way too dark and can create a blotchy mess.
Broad curl woods like Curly Cherry, Flame Birch, etc. can also absorb any colorant unevenly. We've looked at many ways to help control this. I want to emphasize how important it is that you do a test on a scrap before you dive in. With that said, one of my favorite tricks is to use water to help control the absorption. I have used our blotch control and thinned it, you have to experiment with this as there is no set rule and a particular wood you’re using will determine how much you need to reduce the blotch control.
Take a look at this photo. Obviously the side with water is lighter, but when dry, I could do water and another coat of dye. Simply thinning the dye usually does not work because irrespective of how thin the dye is, it's going to migrate into the softer grain thus causing it to be darker. The water trick, has proved to be pretty successful and is one of my go-to techniques, especially on figured maples.
Remember the rule “Sneak Up on It!"
Product of the Month: Aqua Coat Wood Putty
An excellent product because it dries well, accepts stains, and finishes. See what Charles Neil had to say about it in his blog In the Workshop with Charles Neil.
"I have tried the oil based (wood putty) products and found the dry times to be excessive, as well as they tended to seal the wood so stains and so forth could become issues. Then, I gave the water base Aqua Coat Wood Putty a try, and to say I was impressed is an understatement.
I got a piece of red oak, and some African mahogany, I applied one coat, it had a slight cream color to it, but dried in about 45 min to an hour, to totally clear, I then sanded it with some 180, on the oak I wiped some water base stain, and the color between the filled and unfilled sections was identical, on the mahogany, I sanded it, and sprayed a coat of waterborne finish in it, it was smooth as silk…It worked extremely well and it sure cures a lot of ills. Now for those who like to use colored fillers to accent grain, no issue, I can tint it, or color as I wish…all I can say is for me it sure is a welcome product."
Finishing Tip by Bob Flexner: Restoring Life to Dry Wood
The wood in old furniture and woodwork often takes on a dry appearance, and people want to know what to do to restore life to the wood. Because of widespread misinformation from furniture polish manufacturers that wood contains natural oils that need to be replaced by furniture polishes, many people think they need to apply oil to the wood. But the problem is rarely in the wood (and only woods from the tropics contain a natural oily resin anyway). It’s the old finish that has deteriorated and become cracked and crazed that makes the wood appear dry. Light no longer penetrates the deteriorated finish to reveal good depth and color.
There are several ways to restore the depth and color. From least invasive to most, these include:
- Apply paste wax. If the problem is still pretty superficial, the thin wax layer will solve the problem.
- Sand the surface lightly with fine sandpaper to remove the surface roughness, then apply a coat or two of finish. To do this successfully, you’ll need to remove most of the wax, if you tried the wax solution first. You can do this by wiping with mineral spirits or naphtha without damaging the underlying finish. To further avoid bonding problems, use shellac for the finish, because it will bond well over thin wax.
- Worst case, you’ll need to strip the finish and apply a new one. It’s almost always better to use strippers than to sand or abrade off the finish because sanding will cut into the wood and remove the aged color (“patina”) it has developed.
In the example shown in the accompanying picture, paste wax isn’t going to help. It might be possible to smooth the surface with a light sanding, then apply more finish. But the cracking will telegraph through relatively quickly. The best solution in this case, and what I chose to do, was to strip the finish and apply a new one.
Finishing Tip by Bob Flexner: Dry Spray When Spraying Insides of Cabinets
If you have ever sprayed the inside of a cabinet with a fast-drying finish such as lacquer or catalyzed lacquer, you have surely experienced dry spray settling on the surface and causing it to feel rough. The bounce back and turbulence created by the force of the spray keeps the finish particles in the air so long that the finish on the surface has already set up before all of the particles land. And when they do land, they stick to the surface, but don’t dissolve in.
The problem is reduced with HVLP and especially with turbine HVLP because there is so much less force creating bounce back. But in the confined space of a cabinet there’s still almost always some dry spray and some roughness.
Minimal dry spray is difficult to show in a picture. But serious dry spray settling on a surface is easy to show, as on the top half of the panel in the accompanying picture. I’ve often seen instructions to avoid spraying directly into corners in order to avoid the dry spray. Instead, spray the two surfaces that join to form the corner. In other words, make the solution one of spraying technique. But I’ve never found this to work well.
If you think about it, the real cause of the problem is the fast drying of the finish. Slower-drying finishes, such as varnish and water-based finish rarely, if ever, have a dry-spray problem. So the better trick for avoiding dry spray on the insides of cabinets is to slow the drying of the lacquer or catalyzed lacquer by adding a retarder. This keeps the surfaces wet longer, so the dry spray has time to settle and dissolve in, leaving a smooth feel.
You have to be careful, of course, not to retard too much or you’ll have difficulty avoiding runs and sags. So be observant.
Bob Flexner Finishing Tip: Tack Cloths and their Use
Inexpensive tack cloths (tack rags) are available from most suppliers of paints and finishes. They are sticky rags meant for picking up dust, often sanding dust, from a surface just before applying a coat of finish. Here are some tips for using them.
- Limit their use to solvent finishes. They can cause fish-eye and bonding problems with water-based finishes because they leave an oily residue on the surface. Instead of a tack cloth, use a slightly water-dampened cloth to remove the dust when working with water-based finishes.
- Before using a tack cloth on sanded wood, remove the majority of the sanding dust with a vacuum, or blow it off with compressed or turbine air if you have adequate exhaust to remove the dust from the air (so it doesn’t settle back on your work).
- A tack cloth is most effective between coats of finish because there is less dust to remove (so the cloth doesn’t become overloaded too quickly).
- No matter whether you use a tack cloth, vacuum, or compressed or turbine air to remove the dust, wipe over the surface to be finished with the palm of your clean, dry hand just before beginning to apply the finish. This will remove the last of any remaining dust that might have settled, and it will warn you if there is still excessive dust that should be removed with one of the other means.