RECOAT WINDOWS
WINDOW (Hrs.)
TACK COAT RECOAT
24-96
24-72
16-48
12-36
10-24
8-16
WINDOW (Hrs.)
POLYURETHANE OVER POLYURETHANE
Temperature degrees F
60-70
71-80
81-90
91-100
101-110
111-120
Temperature degrees C
16-21
22-27
28-32
33-38
39-43
44-49
RECOAT WINDOW
8-48
6-48
4-36
3-24
2-12
1-2
(Hrs.)
EXTENDED RECOAT
NONE ------------------------------------------
WINDOW (Hrs.)
TACK COAT RECOAT
NO TACK COAT USED -----------------------------
WINDOW (Hrs.)
The temperature ranges shown in the table above are for determining recoat
windows. Choose recoat window based on the highest surface temperature
that was sustained for one or more hours between coats. This applies to
the entire time between coats. Measure and record air and surface
temperatures on hourly basis to determine appropriate recoat windows. If
surface temperature goes above 38 degrees C 100 degrees F, measure and
record temperatures every half hour.
CURE TEST - Where indicated, test surface for cure using high-flash
aromatic Naphtha only (cas #64742-95-6). Do not use aliphatic VMP Naphtha.
Wipe surface with rag saturated with Naphtha, and check for surface
tackiness, loss of gloss, or other indications that solvent has softened
surface. If softening is found on 95% of test sites, this is indication
that coating has not fully cured, and GLOSS REMOVAL is not required if TACK
COAT is applied within three hours and full coat is applied within the TACK
COAT RECOAT WINDOW. Test surfaces at rate of three tests for the first 100
square meters 1000 square feet plus one test for each additional 100 square
meters 1000 square feet or part thereof.
TACK COAT - Where indicated, apply coat of intermediate coat epoxy, at 25
to 50 microns 1 to 2 mils WFT, then apply next specified full coat within
TACK COAT RECOAT WINDOW. Thin TACK COAT material approximately 25% by
volume, using appropriate epoxy thinner.
GLOSS REMOVAL - Where indicated, remove all gloss by hand sanding with
150-200 grit wet/dry sandpaper in a linear fashion, pressure wash or wipe
down with a clean rag soaked with denatured alcohol to remove dust. Do not
use rotary sanders or grinders.
3.7.2
Application of Coating System and Joint Sealant
Apply coatings in accordance with SSPC PA 1 and as specified herein. Apply
coatings to surfaces that meet all stated surface preparation requirements.
After application of primer coat and prior to application of each
subsequent coat, perform testing prescribed in article entitled
"Pre-Application Testing For Surface Contamination," as necessary, to
ensure minimal intercoat contamination. This testing may be reduced to one
half of the prescribed rate for bare steel if the testing indicates no
contamination when sampling is evenly distributed over surfaces being
tested. If contamination is found between coats, revert to the specified
testing rate. Generally, oil and grease contamination and soluble salts
SECTION 09971
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