Almost four decades ago, I apprenticed at a cabinetshop where a regular high-pressure system was used to apply lacquer and stain to kitchens. Despite numerous extraction and filtering devices, the entire building filled up with fumes from the overspray. I would get light-headed and short of breath at times from these volatile fumes, even while wearing a carbon filtered mask. If only we'd known! A couple of years after I left, that shop was destroyed by a fire that started in the spray booth. There was a 1/4" thick residue of overspray on the walls, and it lit up the downtown like a fireworks display. Thankfully, high-pressure spraying is essentially obsolete among woodworkers today.
|In 1971 a new technology was patented by a European company called Sicmo. It sprayed the same finishes as the old guns, but used a whole lot less pressure to deliver the material. That meant there was a lot less overspray - finish sent into the air that never arrived at its destination. The new system came into its own during the '80s and especially the '90s, and its name describes exactly what it does... high volume, low pressure, or HVLP.||
FUJI's Q4 Pro Self-contained system.
Over the next few years, HVLP gained a lot of popularity while small unit manufacturers worked out the bugs and became more and more familiar with its advantages. Many of them concentrated on complete systems like the Fuji shown here, which included an air pump, freeing up small shop compressors for other tasks. Today, virtually everybody setting up a spray operation in a small or medium sized shop goes with this safer, healthier, more economical choice.
So, what exactly is HVLP?
And how does it work?
The Turbinaire HVLP system shown here used "an electric turbine (110v or 220v) to deliver a high volume of air at low pressure to the gun's air cap. When the trigger is activated, the paint is released at the fluid tip and the high-volume low-pressure air atomizes the coating externally as it is being applied." The Turbinaire site also pointed out that conventional spray systems operate at 60-80 PSI @ 8 CFM, which results in a 30-50% transfer efficiency. According to the company, about 60% of the finish never makes it to the project. They pointed out that this is unhealthy for the operator and harmful to the environment. Turbinaire's HVLP systems operated at 4-6 PSI @ up to 130 CFM - a combination that delivers up to 90% of the product to its target.
To do further research, you can find manufacturers such as Apollo, Wagner, Fuji, Graco and SATA
in the 'Finishing Supplies & Equipment' section of our our Links Page.