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Spraying EPDM Liquid
Rubber® |
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Liquid Rubber can be
sprayed using airless equipment. Choosing the proper
equipment, however is key to achieving satisfactory results.
The fluid characteristics of Liquid Rubber produce
considerable pressure drop in the hose so pump size hose
diameter and total length of hose must be chosen carefully
in order to achieve satisfactory results. |
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The following recommendation is for
Graco equipment. Other manufacturers with
comparable pumps may also be used. |
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Liquid Rubber must be thinned with
solvent to achieve a sprayable viscosity. See
recommendations below. |
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Equipment capable of
spraying Liquid Rubber |
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Pump Model |
Max. Pressure |
Fluid Flow |
Hose ID |
Max. Hose Length |
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Graco GH733 |
3500 psi |
3.0 gpm |
1/2 inch |
150 feet |
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Graco
GH3640 |
36000psi |
3.8 gpm |
1/2 inch |
150 feet |
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Roof Rig |
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Gun |
Should be rated for spraying
mastics. A 30-40 inch tip extension is
recommended.
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Tip Size |
.017 to .021 with a 12 inch fan
width
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Thinning Liquid Rubber |
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The "as shipped" viscosity of Liquid
Rubber is 34-37,000 cp which is too high for spraying.
By adding one gallon of Xylene Solvent to a 5 gallon pail
the viscosity drops to 10,000 cp at 75° F. More
solvent may have to be added at lower temperatures. |
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The spray atomization can be improved
using a smaller tip size or adding more solvent to reduce
viscosity. |
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Wash solvent from previous pump cleaning
can be used for thinning after it is strained to remove
dirt. |
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Fasteners |
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Caulking around fasteners is usually not
necessary. The physical properties of the EPDM Liquid Rubber
will produce a longer lasting seal around fasteners than
caulks will because the latter will become brittle with age,
causing loss of adhesion and cracking. |
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It is good practice to brush the rubber
into the fasteners after spray application to ensure
complete coverage. This procedure will be less time
consuming than caulking. |
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Fabric Reinforcing of Seams and
overlaps |
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Tight overlaps and standing seam joints
do not need to be reinforced. |
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Overlaps with greater than 1/16” or
corroded edges should receive fabric reinforcing. |
- Apply a light coat of Liquid
Rubber.
- Center the fabric on the overlap
and roll it out taking care not to create wrinkles.
- Press the fabric down with a
squeegee or wide spatula.
- Spray a full coat of Liquid
Rubber to seal top surface of the fabric.
- Roll back over with a short nap
roller to ensure complete surface coverage.
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Overspray |
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Overspray can travel a long way when
carried by a breeze. Vehicles should not be parked
downwind near the work area. Overspray landing on a
vehicle can be easily removed with Mineral Spirits even
after 24 hours. Thereafter, stronger solvents such as Xylene
will be effective in removing the rubber but may dull some
finishes. |
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Rain Showers or Freezing Temperatures |
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Unexpected rain showers after application
may affect the surface appearance but will not wash the
material off the roof. Temperature drops below freezing will
arrest the cure but will not damage the Liquid Rubber. The
cure reaction will resume again whenever adequate
temperature returns. |
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Cleaning Equipment |
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A three stage flushing is recommended.
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- Add Xylene on top of the
remaining rubber in pail and continue pumping until
Xylene reaches gun. Reduce pump pressure;
add 2-3 gallons of Xylene to pail and spray into pail.
with tip removed for about 30 seconds. Then remove
gun and recirculate solvent for 3-4 minutes. Tilt
pump out of solvent and let air pressure purge the
material in hose.
- Put clean pail with clean Xylene
under pump and circulate at low pump pressure 3-4
minutes. Connect gun without tip for another short
flush, then remove gun. Again tilt pump out of
solvent, let air pressure purge the line.
- Put another bucket with clean
solvent under the pump and circulate for 3-4 minutes.
The solvent should be a little stained by now.
Connect gun with tip and spray about 10 seconds with rag
over the tip.
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The equipment is now ready for the next
use. If work is to continue another day the solvent
can remain in the line if gun is attached. Clean up
solvent should be strained and used for thinning as
application continues. |
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Click here to
Order EPDM Liquid Rubber.
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On some materials, such as
EPDM rubber sheets, some swelling may occur due to solvent
absorptions after applying
EPDM Liquid Rubber®. This
is normal. This swelling will recover with time and heat. In
80° F or so, allow 7 to 14 days to recover. In colder
temperatures, recovering will take several weeks, as much as
6 to 8 weeks in 60° F. |
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The information presented herein is furnished
free of charge and is based on technical data that Pro Guard
believes to be reliable. It is intended for use by persons
having technical skill and is at their own discretion and
risk. Since conditions of use are outside our control we
make no warranties, express or implied, and assume no
liability in connection with any use of this information.
Nothing herein is to be taken as a license to operate or a
recommendation to infringe any patents. |
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