Over 40 years ago it was common to receive a set of accessories when buying a vacuum cleaner for the home. One such accessory was a small plastic spraygun with an attached jar for paint. One end of the hose was attached to the spraygun and the other to the ‘blower’ end of the vacuum cleaner. Surprisingly, if the paint was thinned enough, it would spray quite well.
Although the system lacked power and sophistication - HVLP was born ! It showed that high pressure was not necessary to spray paint. Low pressure could work in exactly the same way - with one major difference - the lower velocity of the air resulted in less overspray and wasted paint.
True HVLP originators such as Sicmo (Monaco) and Apollo (England) built the first professionally used low pressure sprayguns. In fact, until the late 1980’s all other HVLP sprayguns copied these early guns in every respect. The Sicmo spraygun (under different names) is still in use today with no significant changes in decades. Apollosprayers started in England in 1966 and then later in 1981, under John Darroch, became the first HVLP spray equipment manufacturer in North America.
Sicmo was also the first maker of a true HVLP conversion spraygun. Patented in 1971 by its inventor Irmgard Farnsteiner, this spraygun was, and still is, the most air-efficient conversion spraygun. Unlike all other conversion sprayguns on the market today, the Sicmo does not rely solely on ‘restriction’ to lower pressure. In addition to restriction, the Sicmo uses a unique air-entraining venturi to actually increase the volume of air passing through the gun. When broken down, the venturi mechanism itself comprises over 20 different parts - this could be considered by some to be a drawback to the device.
There is probably no area (second to automotive on-board computers) that has changed more than the automotive refinishing business. Environmentally conscious legislation has required that the paints we spray today have more solids (lower VOC's or solvents) and in some areas, in order to appropriately apply these new finishes "legally" a new, more efficient, application system had to be developed.
Paints are applied by spraying them onto a surface. In a typical High Pressure spray gun, the air blowing through the top of a "T" shaped tube (remember how a blast gun works??) pulls the paint up the vertical portion and into the air stream. Additional air passageways focused on the exiting stream of paint atomize (break it up into small droplets) it to provide a smooth finish. The problem is, that to properly pull the paint into the air stream and atomize it requires so much pressure that the paint is blown in a very inefficient pattern. The "old-style" guns waste up to 3/4 of the expensive (it costs about $200 - $500 to buy enough paint to refinish a car) paint. not only can they give you instant BAD NEIGHBOR status, but they also make it tough to see what you are doing!
HVLP (High Volume - Low Pressure) guns generally use much less pressure
to push the paint into the air stream where it is atomized by a higher
volume of lower pressure (10 PSI or Less) air. HVLP produces a gentle,
sharply defines pattern that effectively transfers 3/4 of the paint exiting
the gun to the surface you are trying to paint. I think you can see the
more effective transfer HVLP offers can easily cut paint costs in half!
Some High Volume - Low Pressure guns work with Turbines. Others work with an air compressor. Which type of High Volume - Low Pressure spray gun will work best for you?
First, lets understand the difference between a turbine and an air compressor. Turbines use a series of multi-finned blades spinning at high speed (about 14,000 RPM) to move a high volume of air at a relatively low pressure (about 5 PSI). Turbines are lightweight and provide a reliable source of dry, oil-free air.
An air compressor uses pistons or a diaphragm to push a relatively small volume of air at high pressure into a holding tank. Most spray guns, until about 15 years ago, required an air compressor. The air compressor is capable of pressures of 125 PSI and more, but are heavy, and can produce contaminated air when they are worn out or improperly filtered.
Should I select a
turbine
unit or an HVLP air conversion spray gun to hook up to my air compressor?
The first thing to consider is whether or not you have an air compressor,
if you do you need to check how many horse power it is. Make sure that your compressor is
at least 3 horse power or larger, with at least a 20 gallon air tank. If your compressor
meets these requirement then you have the ability to choose between HVLP
turbine systems or the HVLP air conversion guns. If your compressor does not
meet these requirements, or you do not have a compressor at all, then you
will want to look at the turbine systems. Turbine systems will also give you considerably
more mobility. If mobility is something that is of concern to you then you will want to look at HVLP turbine systems.
My spray finishing needs are only occasional. Will a small turbine system fulfill my needs?
Selecting an HVLP turbine is not based upon the capacity or frequency of use,
but rather what type of coatings you intend to use with your sprayer. If you intend to only
spray thin materials like lacquers and oil based stains then a small turbine will work great.
However, if you intend to spray heavier bodied materials, that cannot be thinned down much,
such as water-borne lacquers and polyurethane's, a larger turbine unit will be necessary regardless of
whether you use it every day or once a month. The larger turbine units have the power it takes to break
down all of the new water-borne lacquers and urethane's.
How do turbine systems differ? There are three parts to a "turbine system", the turbine or motor which drives your air supply and the air hose which delivers the air to a spray gun. The first part of the "turbine system" that you want to look at is the turbine itself. Turbines can differ in the size and the power of the turbine motor, which is inside the case. The size of the turbine motor is directly related to the types of materials that you are able to spray. The quality of the turbine motors used is another important aspect to look at. These can vary according to the brand of turbine you look at. The size of the case that the turbine motor is housed in is one other factor to look at. Some smaller cases are not designed for achieving the maximum life out of the motor. In other words the case does not provide enough room for the motor to get adequate filtration, causing the turbine motor to run hot and ultimately pre-mature bearing failure. Watch out for those small seemingly great little turbines, they can often be just small cases with larger motors which don't get adequate ventilation. Make sure that the turbine unit has ample filtration for the size and type of motor inside. Also, make sure that the turbine unit has at least two filters that are large enough to provide ventilation for the size of motor.
In addition to the turbine unit an HVLP system also consists of an air hose. The air hose used for HVLP is usually either 5/8 inch or 3/4 inch in diameter. Most turbine air hoses are 3/4 inch in diameter. These hoses tend to be very bulky and heavy. They can cause operator fatigue and they lack flexibility. This smaller diameter hose along with the flex whip greatly helps to relieve fatigue associated with long spray jobs and allows the operator to turn the gun in virtually any position with ease. Hose length can also vary from manufacturer to manufacturer. Be careful not to get too long an air line for the size turbine you buy.
The most important part of the "turbine system" is the spray gun. How it is constructed and the tolerances used are critical in achieving high performance and having easy, trouble-free maintenance.
Do air conversion HVLP spray guns work as well as a HVLP turbine spray systems?
HVLP Air Conversion spray guns vary widely. Many guns are nothing but modified
conventional spray guns. Most conversion spray guns consume large amounts of air,
rated in Cubic Feet Per Minute (C.F.M.) and Pressure Per Square Inch (P.S.I.), and thus
require a very large (5 horse power or larger) or dedicated compressor to provide enough air to run them.
A few HVLP makers have disappeared over the years. Some of these names include Sprayfine, Amspray, Capspray and Croix. The latter two names are now associated with Wagner (Capspray) and Graco (Croix).
The following is a list of HVLP spray painting system manufacturers. This is not meant to be a complete list, as there may be other manufacturers of this type of equipment.
Apollo Sprayers International, Inc.
1030 Joshua Way
Vista, CA 92081
Voice: 760-727-8300 x204
Fax: 760-727-9325
http://www.hvlp.com
Apollo HVLP on eBay
Accuspray, Inc.
23350 Merchantile Rd.
Cleveland, OH 44122
Phone: (800) 618-6860 or (216) 595-6860,
Fax: (216) 595-6868
http://www.accuspraydirect.com/
Accuspray on eBay
Binks Manufacturing Co.
9201 W. Belmont Ave.
Franklin Park, IL 60131
Phone: (708) 671-3000
Customer Service Fax: (708) 671-3067
The DeVilbiss Co.
1724 Indian Wood Circle
Maumee, OH 43537
Phone: (416) 470-2169
Fax: (800) 338-0131
http://www.devilbiss.com/
DeVilbiss HVLP on eBay
Graco, Inc.
P.O. Box 1441
Minneapolis, MN 55440-1441
Phone: (800) 367-4023
Fax: (612) 623-6777
Iwata Medea, Inc.
1336 N. Mason
Portland OR 97217
http://www.iwata-medea.com/index.php
Iwata on eBay
Fuji Industrial Spray Equipment Ltd.
40 Magnetic Drive, #58
Toronto, ON M3J 2C4
http://www.fujispray.com
[email protected]