SikaEmaco® 425 Gel Patch

SikaEmaco® 425 Gel Patch is composed of crystalline (quartz) silica and Portland cement.

12 months when properly stored

Store in unopened containers in a cool, clean, dry area

*At 50% relative humidity

Bond Strength

Linear coefficient of thermal expansion

Scaling Resistance

Working Time

20-30 min at 70° F (21° C)

0.43 ft³ per 43 lb bag (0.012 m³ per 19.5 kg bag)

• Do not bridge moving cracks or joints.
• Do not overwork material
• Do not add plasticizers, accelerators, retarders, or other additives.
• Do not extend with aggregate.
• Bonding agents are recommended for large areas as well as permanently damp areas.
• Protect from freezing for 24 hours after application.
• For professional use only; not for sale to or use by the general public.
• Make certain the most current versions of the product data sheet and SDS are being used.
• Proper application is the responsibility of the user. Field visits by Sika personnel are for the purpose of making technical recommendations only and not for supervising or providing quality control on the jobsite.

1. The substrate must be structurally sound and fully cured (28 days).
2. Saw cut the perimeter of the area being repaired into a square with a minimum depth of ¼" (6 mm).
3. The surface to be repaired must be clean, free of laitance, and saturated surface-dry (SSD) following ICRI Guideline no. 310.2 to permit proper bond.

Reinforcing Steel

1. Remove all oxidation and scale from the exposed reinforcing steel in accordance with ICRI Technical Guideline No. 310.1R.
2. For additional protection from future corrosion, coat the prepared reinforcing steel with Sikagard® P 8100 AP.

1. Precondition material to 70° F ±5° (21° C ±3°) before mixing.
2. Mechanically mix at a slow speed with a 3/4" drill and mixing paddle.
3. Add approximately 23/4 quarts (2.6 L) of potable water into a clean mixing container. Gradually sift in powder 1⁄3 at a time while mixing continuously at a slow speed (high speeds may entrain air). Mix for a minimum of 3 minutes to ensure a uniform, lump-free consistency. Do not exceed a total of 3 quarts (2.8 L) of mixing water per 43 lb (19.8 kg) bag.

1. Dampen the surface with potable water; it must be saturated surface-dry (SSD) with no standing water.
2. With a gloved hand, scrub a small quantity of mixed material into the SSD substrate. Thoroughly key in and work the material throughout the cavity to promote bond. Do not apply more of the bond coat than can be covered with mortar before the bond
3. coat dries.
4. Apply material in lifts of 1/4–2" (6–51 mm). Avoid feather edging. For optimum mechanical bond on successive lifts, thoroughly score each lift and allow it to reach the initial set before the next layer is applied. Placement time is 20–30 minutes at 70° F (21° C) and 50% relative humidity.
5. Trowel, shave, or shape the material to the desired finish after the initial set.
6. The recommended application range of SikaEmaco® 425 Gel Patch is from 40 to 90° F (4 to 32° C). Follow ACI 305 and 306 for hot or cold weather guidelines.

Cure with an approved water-based curing compound compliant with ASTM C 309 or preferably ASTM C 1315. If the repair area will receive a coating, wet curing is recommended.

Clean tools and equipment with clean water immediately after use. Cured material must be removed mechanically.