SILCOR® Fast Set Primer is a two-component fast curing, short recoat time urethane primer for concrete substrates specifically designed for the SILCOR® 900MP liquid waterproofing membranes.
- Fast curing with short recoat time : Minimum 20 minute recoat time at 70°F (21°C)
- Easy to apply by spray or roller or brush
- Convenient for large size jobs (10 gallon kit)
- Simple mix ratio (1:1 ratio by volume)
- Excellent adhesion exceeds concrete cohesive strength
- Can be applied easily from 40°F to 100°F (4-38°C)
- Can be applied over wood, concrete and steel after relevant prep of substrates
1. Surface Preparation
- Minimum pull-off adhesion strength of the concrete substrate as determined by ASTM D4541 or ASTM D7234 shall be115 psi for limited access roofs and 215 psi for vehicular trafficked decks. Where these values are not achieved by pull-off adhesion testing, remove all laitance by shot blasting.
- Surfaces must be clean, sound, free of dust, laitance, sealers, grease or any other contaminants that might reduce adhesion.
- If power washing the substrate, allow sufficient time for the residual humidity to dissipate. The substrate moisture content before application of the primer must be less than 5%. The primer surface before application of SILCOR® 900MP liquid membrane must be clean and dry.
- Store SILCOR® Fast Set Primer in a dry and cool place out of direct sunlight.
- Add the complete quantity of the B-component to the A-component to assure correct mixing ratio.
- Mix with a slow turning mixer (less than 300 rpm) for 3 minutes in order to obtain a homogeneous mixture.
- The application temperature range is 40°F to 100°F. Higher temperatures reduce the pot-life considerably.
- Apply SILCOR® Fast Set Primer to the surface by brush or roller immediately after mixing ensuring coverage of the entire surface.
- Pour the primer onto the surface in a zigzag pattern.
- After pouring onto the surface, distribute the primer evenly with foam rubber squeegees and roll using Perlon rollers.
- The primer should be evenly distributed at 10 mils thickness with complete coverage of the surface.
- If the surface is very porous and absorbs primer to the extent that open surface remains additional primer must be added in this area within the pot life or recoat time of the primer.
- The SILCOR® 900MP membrane should be applied within 24 hours. This window is influenced by ambient temperature and humidity. When this time is exceeded before the membrane is applied, re-apply a new layer of SILCOR® Fast Set Primer.
- SILCOR® Fast Set Primer has excellent wetting and soaks into the concrete surface, tack free time is not a good indicator for recoat time. GCP recommends recoat time with adhesion strength testing according to ASTM D4541.
|Ambient & Substrate Temperature||Minimum Recoat Time|
|95°F (35°C)||10 minutes|
|70°F (21°C)||20 minutes|
|40°F (4°C)||30 minutes|
- Mixing and application equipment should be cleaned immediately with mineral spirits. Remove hardened material mechanically. All solvents should be used only in accordance with manufacturer’s recommendations. Do not use solvents to clean hands or skin.
|10 GALLON KIT||APPROX. UNIT OF SIZE|
|SILCOR® Fast Set Primer Part A||5 gal (iso)|
|SILCOR® Fast Set Primer Part B||5 gal (resin)|
|Solid Contents||96.4% ASTM D2369|
|Working Time, cup, 70°F (21°C)||20 minutes|
|Concrete Adhesion||1,000 psi (6.9 MPa) or substrate failure ASTM D4541|
|Steel Adhesion||1,000 psi (6.9 MPa) or substrate failure ASTM D4541|
|Mix Ratio (by Volume)||1:1|
Approximately 192 ft2/gal (1,920 sqft/10 gallon kit), actual will vary depending on the absorption and profile of the surface.
SILCOR® Fast Set Primer should be stored and shipped in clean, dry, low-humidity, and shaded or covered environments in original sealed containers between 50°F (10°C) and 90°F (32°C). Shelf life is 1 year in unopened containers stored under the conditions described above.
Health and Safety
Read the product label and Safety Data Sheets (SDS) (SDS A) (SDS B) before use. SDSs can be obtained from GCP Applied Technologies.
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Last Updated: 2023-06-28