Technical Data & Application Instructions
Corrosion Resistant Polyurethane Primer
PRIMER 302 is manufactured in Light Gray color only.
PRIMER 302 can also be used beneath an approved topcoat under constant immersion conditions.
2. Mixed Usable Pot Life: 24 hours at 75°F (24°C), 50% R.H.
3. Solids by Weight (Mixed): 51% (+2) [ASTM D 2369]
4. Solids by Volume (Mixed): 34% ( + 2) [ASTM D 2697]
5. Flash Point: Part A: 40°F (4°C) Part B: 80°F (27°C) [Seta-Flash closed cup]
6. Temperature Limits for Service Conditions: -70°F to 200°F (-56°C to 93°C)
7. Dry Time: 30 minutes at 75°F (24°C), 50% R.H.
PACKAGING & MIXING
Mix 4 VOLUMES OF PART A WITH 1 VOLUME OF PART B. THINNING OR REDUCING THE MIXTURE IS NOT NORMALLY RECOMMENDED. If thinning is desired, used Methyl Ethyl Ketone (MEK) only. Material shall be thoroughly mixed prior to application. Use an air-operated or other explosion-proof mixer, which has been grounded and bounded, with a blade capable of uniformly mixing entire container.
Allow mixture to set a minimum of twenty (20) minutes for sweat-in before using. Mixed usable pot life of the mixture is 24 hours at 75°F (24°C), 50% R.H. At higher temperatures, usable pot life is shortened.
Shelf life of Part A and Part B components in unopened containers is one (1) year. Store at temperatures between 50°F and 100°F (10°C and 38°C). Do not open containers until ready to use the material.
PERFORMANCE & ADVANTAGES
1. Resistance to Condensation*:
3. Resistance to Salt Spray*:
5. Resistance to Impact**:
6. Bond Strength:
7. Cathodic Disbondment:
8. Low & High Temperature Applications:
9. Fast Cure Time:
*Note: These tests were conducted using cold rolled steel panels Steel panels were sandblasted to Near-White (SP10) and then primed. PRIMER 302 was spray-applied in one coat to a minimum thickness of 1.5 dry mils [38 dry microns]. Test panels were than allowed to cure at 75°F [24°C], 5% R.H. for 6 days and then oven dried at 125°F [52°C] for 1 day before testing.
**Note: This test was conducted using stainless steel panels. Stainless steel was acid cleaned using 10% muriatic acid and then primed. PRIMER 302 was spray-applied and cured in the same manner as listed above.
PREPARATION OF STEEL SURFACES
Steel and fabrication defects, such as weld imperfections, delamination's, slivers, etc., should be corrected prior to starting abrasive blasting operations.
All previous paints or coatings on the substrate must be completely removed, including paints or coatings which are tightly adhered to the surface.
All burrs, jagged edges, undercuts, recesses, and surface defects shall be ground smooth. Porous welds shall be ground down to pinhole free metal.
Steel surfaces must be blast cleaned to either Near-White (SP10) or White Metal (SP5) depending upon the conditions under which the topcoat will be subjected to on a specific project. Wet or water vapor sandblasting is not recommended.
The following cleaning procedures are provided for guideline use only. Occasions will arise where the specified method of blast cleaning will not result in the achievement of the type of cleaning desired. It is suggested that Technical Service be contacted for recommendations on each specific application.
Cleaning procedures as specified herein shall be in strict conformance with the following applicable Steel Structures Painting Council (SSPC) Surface Preparation Specifications:
SSPC SPA Solvent Cleaning
All oil, grease, weld flux, and other surface contaminants shall be removed prior to blast cleaning by use of a solvent wash as defined in SSPC SP1 Solvent Cleanings
Excessive rust-scale shall be removed by mechanical means prior to blast cleaning.
Abrasive blast cleaning shall not be performed when surface temperature of the steel is LESS THAN 5°F (3°C) above the dew point of the ambient air when relative humidity exceeds 80% or when there is a possibility that the blasted surface will become wet before the primer can be applied.
The blast cleaned surface shall be primed by the end of the same work day, but in any event before any visible rusting occurs. If rusting occurs after blast cleanings the surface shall be reblasted before priming. If the steel surface is subjected to chemical contaminations priming of the blast cleaned surface must take place as soon as possible.
For inspection purposes the visual standards contained in the Pictorial Surface Preparation Standards For Painting Steel Surfaces, SSPCVIS 1-67T shall be used as a guide in determining the minimum degree of surface preparation.
Surface Preparation Specifications: NACE No. I (SSPC-SP5); NACE No. 2 (SSPC-SP10) and NACE Standard TM-01-70 (SSPC-VIS1-67T).
STEEL SUBJECT TO DRY ABRASION
1. Lightweight Abrasive Materials:
2. Lightweight to Medium Abrasive Materials:
3. Heavy Abrasive (Larger than 1"):
STEEL SUBJECT TO LIQUID SLURRY:
1. Plain Water and mineral Solids:
2. Light Slurry with Lightweight to Medium Particles:
3. Heavy Slurry:
Prior to the application of primer, all loose dust and blast particles shall be removed from the surface by use of a power vacuum. Dry air blow off and brush cleaning are not recommended.
Note: The above surface preparations as defined by the National Association of Corrosion Engineers are comparable to SSPC Surface Preparation Specifications: NACE No. 1 (SSPC-SP5); NACE No. 2 (SSPC-SP10) and NACE Standard TM-01-70 (SSPC-VIS1-67T).
Coverage rate will depend upon the surface profile. For surfaces which have been sandblasted to a 2 mil profile. PRIMER 302 should be applied at a minimum rate of 1 gallon per 250 to 300 sq. ft. [6.1 to 7.3m2/1] of surface area. This coverage rate should result in 1 to 1.5 dry mils [25.4 to 38 dry microns]. Surface profile and application conditions will affect coverage rate.
Consult Technical Service for minimum dry mils thickness recommendations when steel surfaces are sandblasted to a surface profile greater or less than 2 mils.
Spray gun should be held not more than 24" from, and at a perpendicular angle to the surface being primed. As PRIMER 302 is an ultra-fast drying primer, it will begin to dry, or "powder" if the spray gun is held too far away from, or at a severe angle to the surface. Primer which is powdered onto a substrate does not wet into the surface adequately to achieve proper adhesion. Powdering exhibited on particular PRIMER 302 applications can be eliminated by thinning with up to equal parts of M.E.K.
When PRIMER 302 is applied over stainless steel or aluminum, apply primer to a small test area to ensure proper adhesion. Due to the various types of stainless steel and aluminum, preparation of the surfaces to receive PRIMER 302 may require a different procedure from than that stated above. For any primer to function as it was designed, proper surface preparation is essential in attaining optimum adhesion.
PRIMER 302 should be topcoated on the same day. If topcoating can not be achieve within 48 hours, consult Technical Service for recommendations.
LIMITATIONS & PRECAUTIONS
Solvents are flammable. Use only in a well ventilated area. Keep away from heat, sparks, open flame and lighted cigarettes. Use explosion-proof application equipment.
Avoid prolonged or repeated breathing of vapor or spray mist. Approved (MESA/NIOSH) chemical cartridge respirators should be worn by applicator. Avoid contact with eyes and contact with skin.
For additional information on safety requirements, refer to OSHA guidelines and PRIMER 302 Material Safety Data Sheet.
The Rot Doctor, Inc.
P.O. Box 30612 • Seattle, WA 98113
Voice: 206.364.2155 • Fax: 206.364.4744
© 1997-2012 The Rot Doctor, Inc.
Our business hours are 6:30 AM to 5:30 PM Pacific Time, Monday-Friday.
Tech support is available over weekends.