Spray Finishing
by Alan Noel
Professional Wood Finisher
This article first appeared in the October 2008 issue of Wood News.
When it comes to ease of application and total control, spray finishing with either HVLP (high volume, low pressure) or conventional compressed air and suction/gravity feed spray guns is definitely the way to go.
Applying finishing materials with a brush can be a very slow and arduous task. It is virtually impossible to get an even coat on large surfaces when using a brush. Also, one is limited in the coloring process simply because stains or dyes have to be applied first, left to dry for hours or days. Afterwards when a coat of finish is being brushed on, the underlying stain can be "dragged" along because the solvents present in the top coat can soften the stain binder.
This is precisely why spray finishing is a much easier way to achieve a great finish with much less effort while enjoying virtually total control throughout the entire process. It is far easier to apply a more even coat of material overall, stains, dyes, and glazes can be layered between coats however, spray finishing also has it's limitations too. The most important being used in the right environment with safety at the top of the list.
Here are NINE helpful tips to consider:
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HVLP systems are usually sold as a complete unit consisting of a spray gun, connecting hose, and a turbine unit that supplies the air.
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Conventional spray systems include a compressor with a built in air regulator, an in-line moisture extractor, connecting hose and spray gun.
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While you can use both systems to spray outside, both systems were designed for use in a spray booth specifically designed for this use.
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HVLP systems have a far better material transfer rate than conventional systems. HVLP systems require much less air to operate, and therefore create less over spray. This allows for much more material to be delivered to the surface making HVLP a more efficient system.
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Spraying anything other than water-based materials (e.g., shellac, lacquer and oil-based finishes) creates a dangerous environment. Both systems atomize finishing materials at the nozzle, creating a very fine mist that can cause an explosion under the right circumstances. This is why an explosion proof spray booth is necessary to use these tools properly.
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With proper ventilation, the HVLP system is ideal for use on-site when finishing kitchen and bathroom cabinetry or surfaces because of the low over-spray factor.
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Although water based paints and finishes can be sprayed with both of these systems, the thinning required and slow dry time makes it very difficult to apply without the material running on vertical surfaces.
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As with any finishing materials, proper attire is a must. Respirators must be worn at all times when using spray equipment. Safety goggles, gloves, long pants and sleeves are also highly recommended.
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If at all possible, visit a working cabinet or restoration shop for more info and advice on the use, care and maintenance of spray equipment.
Visiting Atlanta? Check out Alan's Spray Finishing class in person, or attend another one of Alan's upcoming highly informative Highland Woodworking wood
finishing seminars:
September 11
French Polish Workshop
September 28
Spray Finishing
October 2
Finishing the Finish
October 12-13
Antique Restoration
October 19
Finishing 101
Visit Highland Woodworking's Online
Wood Finishing Supplies Department
Alan can be reached directly via email c/o Alan Noel Furniture Refinishing at
anoelfurniturere@bellsouth.net
.
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