Waterborne finishes have been around for decades now, but
they still don't seem to have caught on with painters in parts
of the country where regulatory rules don't mandate their use.
Early formulations are partly to blame for this lack of
popularity: Temperature sensitivity, incompatibility with
additives like tints and flow enhancers, sanding problems, and
unfamiliar application methods have all made waterbornes
unattractive to production-oriented painters.
However, the good news is that the technology has evolved,
driven in part by the EPA and states like California that place
restrictions on VOCs (volatile organic compounds) in paints and
stains. Waterborne finishes are now in their fourth generation
— at least — and have reached a point where their
advantages could make them attractive to even the most
Disadvantages of Solvents
I'm a remodeling contractor who prefers to do his own painting.
My own move to waterborne lacquers, specifically for finishing
interior trim on remodeling jobs, was driven not by state
environmental regulations, but by the desire to cure the
headaches — both figurative and literal — that
other products were giving me. Solvent-based lacquers, for all
their advantages, aren't high on my list of favorite
For example, spraying lacquer in a basement during winter
presents some real difficulties. The furnace can't be on,
because it poses a safety hazard — one spark amid all
those volatile fumes could spell disaster. The same goes for a
gas-fired water heater.
And those fumes — isobutyl acetate, naphtha, xylene,
methyl ethyl ketone, and toluene are all common lacquer
solvents — migrate throughout the house no matter how
well you mask and tarp the job, and tend to linger for days.
This drives live-in remodel clients to various degrees of
discomfort and dissatisfaction, depending on their age and
health. I don't like working in the leftover fumes myself, and
neither do the subcontractors on my jobs — which is why I
decided to find a better way.
I began by discussing my concerns about spray-applied
waterborne finishes with my Sherwin-Williams sales rep. He's
used to working with painting contractors whose bottom line is
time and money, so initially he tried to discourage me from
spraying the product I chose, Sher-Wood Kem Aqua Lacquer,
because it's not as familiar or as simple to work with as other
finishes. But he agreed to assist me and showed up the first
time I sprayed a remodeled basement to see for himself and
formulate his own opinions.
Since that trial run, I've decided that waterborne lacquer is a
good fit for my business. It applies easily, albeit a little
differently than a solvent-borne lacquer. The cure time doesn't
affect job progress, the dried finish is very
abrasion-resistant and bonds to virtually everything (you can't
get it off your watch face or glasses to save your life), and
its low odor dissipates rapidly. Furthermore, the fumes and
overspray don't present a fire hazard.
As with any finish, working successfully with a waterborne
lacquer depends a great deal on the amount of time spent in
preparation; fortunately, preparing for a waterborne lacquer is
not very different from the steps commonly taken for
solvent-based lacquer applications.
First, the work area needs to be reasonably clean. I sweep the
floor, use a shot of compressed air to make sure that any
debris stuck under the baseboards won't come flying out during
spraying and stick in the finish, and carefully vacuum the area
(see Figure 1). I also remove unnecessary materials and
equipment from the area to be sprayed. Tools and other items
left lying around get in the way of the hoses and risk running
into a wet finish.
Figure 1.To make sure construction dust won't end
up embedded in the finish, the author hits baseboards with a
blast of compressed air, followed by thorough vacuuming. The
first coat of sanding sealer requires the lion's share of the
Since the moldings and doors I install are typically of a
higher-than-standard quality and are more or less ready to
finish, I don't have to do a lot of sanding before applying the
sealer coat — just what's needed to remove random scuffs
or other obvious marks on the wood. I take the doors off the
jambs and remove the hinges and other hardware, then stand them
up accordion-style, tacked together with door cleats, on rosin
paper. I mask the window glass but generally not much else,
because the overspray is hitting only the primed drywall, which
I finish-paint later, after masking the dry trim (Figure
Figure 2.The lacquer goes on the trim before the
walls and ceiling are painted, so masking is primarily limited
to protecting window glass (left). However, closet ceilings are
considered finished after the drywall primer and top coat, so a
little extra protection is called for in these areas
Gun setup. The spray setup I use
includes a Binks pressure pot and a 2001 SS gun (ITW Industrial
Finishing, 888/992-4657, www.binks.com; Figure 3.) A cup gun
(suction feed) or a gravity feed gun would also work, but I
like the pressure pot. I have to fill it only once, and I find
that the spray pattern is easier to fine-tune when I'm not
borrowing air from the cap to suction the fluid.
Figure 3.The author's spray equipment includes a
compressor (left) that he uses far more commonly to drive nail
guns than to power the pressure pot. Any compressor capable of
delivering 80 psi is adequate for painting. The pressure pot
itself (right) consists of a 2.8-gallon reservoir and an
airtight lid equipped with air and fluid outlets, each
independently regulated. The pressure pot allows a high degree
of control over air and fluid delivery to the gun, which has a
direct effect on the quality of the spray job.
The most important difference between a pressure pot and an
airless rig is the ability to fine-tune the spray (see
"Why I Use a Pressure Pot"). The lower
viscosity of a waterborne lacquer makes runs and sags more
likely than with a solvent-based lacquer, especially on
vertical surfaces. A few runs are inevitable, regardless of the
spraying method used. But as long as the finish hasn't yet set
up, it takes only a little solvent alcohol on a rag to wipe
away a run or sag before respraying.
The ideal coverage is an even coat that just wets the surface.
For painters not accustomed to spraying waterbornes, it may
take a couple of practice attempts to determine the appropriate
film thickness without getting runs.
Fluid prep. In the can, sanding
sealer — I like Sher-Wood Kem Aqua Lacquer Sanding Sealer
— looks something like dirty milk (Figure 4). It's very
important to stir it thoroughly before spraying, as waterborne
lacquer has a relatively high solids content and all the
goodies that you want to land on the trim can settle to the
bottom of the bucket instead. I also routinely strain my
finishes as I fill the pot; any lumps not reintegrated into the
lacquer could be delivered to the gun and cause a nuisance
clog. The paper filters are cheap — about 20 cents apiece
— and generally prevent this kind of problem.
Figure 4.In storage, solids in the waterborne
lacquer settle quickly to the bottom. Even after a thorough
stirring, lumps may linger and cause gun clogs if delivered
from the pressure pot. Straining through a 20-cent paper filter
eliminates most of that risk.
I Use a Pressure Pot
Most production painters rely heavily on an
airless pump rig. Once in a while, you might run
across someone who uses a turbine HVLP (high-volume
low-pressure) outfit or who came from an automotive
background and so knows how to use a cup sprayer.
But an airless rig is for production, period. I
prefer a pressure pot.
With an airless sprayer,
you have limited ability to adjust the pattern of
what you're spraying. You can adjust the pressure
of the pump, which to some extent will affect your
fan pattern, and you can change tips, which also
affect the fan, but if you pick a #312 tip (3 =
radius at 12 inches from surface; 12 = a .012-inch
opening) for doors, you get a 6-inch fan. And you
get it fast.
Also, you can't really do much tweaking. Spraying
lacquer with an airless isn't something for the
slovenly. You have to move right along, practically
fast-walking the house, while controlling the gun
at the same time. Plus there's the problem of
viscosity: Lacquer is thick and sticky, while
waterbornes are thin and runny, and will come
flooding out of an airless rig.
Suction-feed guns are
common in auto-body work — these have a gun
mounted directly on an underslung fluid reservoir
(a similar gravity-feed system mounts the reservoir
on top of the gun). Compressed air travels through
the gun and exits the "air cap" through holes in a
pair of protruding tabs. The center of the air cap
is behind these holes and creates a vacuum whereby
the fluid is drawn to the cap. Depending on the
viscosity of the lacquer, you may be "borrowing" a
considerable percentage of the input air to draw
the fluid to the cap, which can adversely affect
uniform flow. This in turn generates irregularities
in the spray delivery and pattern.
A pressure pot separates
the fluid reservoir and the gun. Two hoses connect
them, one for fluid and one for air. Usually, each
line has a regulator that controls the delivery
pressure independently; no more borrowing air to
drive the fluid. The fluid is driven by direct air
pressure while the cap does its job of atomizing
the finish, just as with a suction or gravity
setup. But because they're delivered separately,
both fluid and air pressure remain more
A conversion spray gun
presents another option. Conversion spray guns are
a newer breed that give you HVLP efficiency using a
compressor rather than a turbine. But the amount of
air required to drive a conversion rig surpasses
the output of most portable compressors. And HVLP
outfits use guns with mounted reservoirs that
require frequent filling, which slows production.
For me, the pressure pot and a conventional gun is
just the ticket — a setup you can tune like a
Once the cleaning and prep-work are done, spraying is a
relative breeze. I plug in the compressor, attach an in-line
filter to catch any debris or moisture coming from the
compressor, hook up the pot, and try to situate the equipment
in the room so that there's little need to move anything but
the gun. I always work back toward the compressor, so that I
can periodically retrieve the hose without any risk of dragging
it against a wet surface. On the regulators, I typically set
the air pressure at around 30 psi and the fluid pressure at
around 7 psi (Figure 5). That seems to yield the best pattern
and the best results on base trim.
Figure 5.The author typically sets the air and
fluid regulators on the pot at 30 psi and 7 psi, respectively.
Further adjustments at the gun determine the ideal fluid
delivery for the spraying task at hand.
When I'm done spraying all the narrower pieces, I simply
increase the amount of fluid and widen the pattern at the gun
for doors and built-ins (Figure 6). A dual regulator setup on
the pot eliminates the need to mess with the settings on the
compressor itself, which are far less accurate than those that
come on a pressure pot.
Figure 6.Narrow pieces like baseboard and standing
trim call for a narrower fan spread (top); for wider areas such
as doors and built-ins (bottom), the author uses dial controls
at the back of the gun to widen the fan spread.
Dry time. I don't know how often I've
heard or read the complaint that waterbornes take a prohibitive
amount of time to dry. I don't buy it. Like any other finish,
waterbornes are affected by temperature and humidity, but the
lacquer I use dries to the touch in about 10 minutes, on
average. On a very humid, cool day, with the windows open, the
longest I have waited is maybe a half-hour. Generally, by the
time I'm done spraying and have the gun flushed for the top
coat, things are dry enough to begin filling the nail holes
Figure 7.It's important to thoroughly flush the
hose and gun between sealer and top coats, as well as on
completion of spray operations. Clean water is all that's
required, followed by a flush of solvent alcohol to aid
Cleanup. With only water as the
primary flushing agent for the gun and lines, cleanup is a
complete snap. First, I rinse out the pot by hand; then I fill
it with clean water and run that through the lines and gun into
a bucket until I see the spray run clear. Next I run denatured
alcohol through the lines after flushing, to remove residual
water and dry them out. I learned the hard way not to slack off
on this routine: If you don't get all the lacquer out of the
system, and the equipment then sits idle for a couple of
months, the residue turns to an orange gunk that clogs the gun.
I have spent probably a couple of hours with Q-tips, pipe
cleaners, dental picks, and lots of methyl ethyl ketone
cleaning the stuff out. But if you really flush the lines and
gun thoroughly, water is all it takes.
Filler. Between the sealer-coat and
top-coat stages, I fill nail holes. The sealer coat takes the
trim close to its final shade for a better color match, and
also helps prevent oil in the filler from bleeding out into the
surrounding wood. I really like Color Putty filler (Color Putty
Co., 608/325-6033, www.colorputty.com). I carry a little
toolbox with just about every color made. To match the wood I'm
spraying, I always mix the putty in my hand (Figure 8). Once I
feel the color is good, I mix it with whiting — a powder
available at almost any paint store — until it's dry
enough to almost crumble. The whiting dries out the putty and
helps avoid oil spots on the trim. That's one area where the
waterborne is likely less forgiving than the solvent-borne
— it doesn't stick to oil — so getting the filler
nice and dry alleviates that concern.
Figure 8.After spraying the sealer coat, the
author uses colored putties to fill nail holes. The putty can
be intermixed to obtain a close match with the finish work. The
author adds whiting to absorb the oil in the putty, thereby
preventing wetting of the surrounding wood. Waterborne lacquer
doesn't adhere to oil.
Sanding sealer is designed to be sanded, and it should be.
Waterborne lacquer will raise the wood grain and leave little
fibers standing up and waiting to be knocked down. In my
experience, this effect is more pronounced on veneer pieces
such as hollow-core doors and prefab jamb stock than on solid
I judge how much sanding I need to do by feel, and use a fine
sanding sponge on occasion, but the vast majority of the time I
find that a lacquer pad — like a scotch-type pad but less
abrasive — does a fine job (Figure 9). The sealer doesn't
need to be sanded for better bonding with the top coat, but
simply to get the nubs off and remove any filler that's left
proud of the surface.
Figure 9.A lacquer pad smooths the roughness left
by the sealer coat, which raises the wood grain slightly.
Lacquer pads have the added benefit of capturing most of the
residual dust, ensuring a particle-free top coat.
It's important to eliminate any debris from the trim after
sanding. Though the lacquer bonds quite well to previous coats,
it will not remelt them as solvent-based lacquers do, so any
white dust left on the base will be permanently embedded in the
finish if you don't remove it first. This is another good
argument for using a lacquer pad, which seems to pick up about
99 percent of the dust.
Once you're ready to spray the top coats, all of the prep and
fuss is behind you. I increase the fluid pressure just a touch,
trying to skirt the fine line between a nice thick coat and
having curtains of lacquer draping down my doors. The top coat
has a higher solids content than the sealer and allows a higher
build — another difference, actually, between
solvent-based and waterborne lacquers. The higher solids
content in a waterborne lacquer allows the same total build
using fewer coats. While a single top coat over the sealer
generally looks good, two will give you a high-quality job. A
light scuffing with a lacquer pad between coats helps ensure a
smooth, professional finish.
While waterborne lacquers typically provide a very clear,
colorless film over the surface (unlike solvent lacquer's
inherent amber hue), one thing I've really come to appreciate
about them is the ease with which they can be tinted. It's fine
to top-coat with a waterborne lacquer over a fully dried
oil-based stain, but I prefer to use water- or alcohol-soluble
dyes (Figure 10). The primary advantage here is that a dye
finish dries fast, whereas an oil-based stain can have you
waiting as long as two days before it's cured enough to
top-coat with a waterborne finish.
Figure 10.To warm up the finish over certain wood
species, the author adds dye directly to the lacquer, which is
otherwise characteristically quite clear and "cold"
The TransTint Dyes (Homestead Finishing Products, 216/631-5309,
www.homesteadfinishing.com) that I like are
also useful for tinting the sealer coat, something I do when
applying a natural finish over oak to help overcome some of the
blander grain areas common to the species. For example, on
natural oak I try to add just a touch of both reddish brown and
honey amber to approximate the amber tinge that a solvent-based
lacquer would impart.
I don't really notice a visible difference in the finish over
stained woods that have a moderate color to them, but both
natural finishes and very dark colors tend to need some warming
up. Walnut is a good example of a wood that can look frigid
when finished natural without a little amber coloring
Should You Switch?
Overall, making the switch from solvent-based lacquer to
waterborne is a step that some may find advantageous. I've
enjoyed the benefits in adhesion, the low VOC content, and the
fairly easy application process. I won't argue that it's for
everyone: If I were running a completely production-driven
paint crew, I might be hard-pressed to switch.
But if you are already considering making that change, whether
because of regulatory increases or — as in my case
— for personal reasons and to please customers,
waterbornes are definitely worth looking into.
Randal Weberis a remodeling
contractor in Lincoln, Neb.