Surface Preparation

Concrete Water Tanks

To repair concrete water tanks Mr Crystal has a chemical reaction with the concrete therefore it is important that it is in direct contact with it. Surfaces to be free from grease, oil, efflorescence and other contaminants. Also, concrete is like a big hard sponge….we want this chemistry to migrate into it, therefore we must take care not to polish the surface such as with a wire wheel. With tanks and troughs you can use a scraper or shovel, a chipping hammer, angle grinder or pressure cleaner. With a grinder, remember, you are not trying to cut concrete…. just “bullying” the contaminants off the surface. Structure to be repaired must have basic structural integrity. Clean out and patch cracks larger than 1.5mm thick with a sand and cement render*. Wet down thoroughly the surface to be coated immediately prior to application.
*3 parts sand & 1 part cement is cheap to use and will crack in a hairline which Mr Crystal can then repair.

Temperature

For “easiest” results, apply Mr Crystal when temperature is between 10C – 25C.

Mixing

Mix only the amount that can be used in a few minutes. Mix with water and bring to a thick paste. Mix thoroughly and add water or product to bring the mixture to a thick creamy, yet just paintable consistency. The final ratio should be about 1kg powder to 375 mls. water. (This can vary widely with your conditions & situation so always mix a small test batch first).

Application

Mr Crystal to be applied to wetted concrete (splash some water on the crack as you go). Apply a strip of mixture 60mm wide with the enclosed brush directly over the crack, working the mixture well into voids. You may notice that the first coat appears patchy. As this first coat begins to go tacky, apply a second coat. The “tacky” first coat will “grab” the second coat enabling you to build the mixture up to a total of 6mm thick. Don’t be alarmed if a little washes off….it is not a membrane. Provided the intact material receives a little moisture crystal growth will start to occur. You will start to see results in the 3-7 day period. It takes up to 21 days to achieve full potential.

Where to Apply Crystalfix

Mr Crystal can be applied over or adjacent to cracks, suspected weak points, cold joints, porous surfaces, around fittings. Mr Crystal can be applied to either side of the face of the concrete. Mr Crystal migrates through the voids in the concrete and will migrate usefully up to 400mm from the point of application. The resultant crystal growth is the waterproofing effect of this product. The raw product itself is not waterproof (in fact, it is highly absorptive by design).

When applying Mr Crystal where there is flowing water, remember not to be too concerned that some product may wash off. It is important to focus on the intact material (that hasn’t washed off) to ensure that it is correctly applied, cured and stimulated. Allow some time for crystal growth to occur ( a few days) then apply some more if needed.

Tip

If the water is running down a vertical crack and washing the material off, try this. Find the exact point of the leak and apply a sharp crack with an engineers hammer. This will compress material into the leak to temporarily reduce the flow during application. Even a sideways (45deg.) scratch will take the water to the side, thus running down beside the crack.

Curing

Protect the surface from rain or frost during initial cure. (Aprox 2-3 hours). Water cure the treated surface by mist spraying with water 3-4 times daily for 3 days if you wish to hasten the crystal growth. This is helpful on structures that are not intended to hold water. (Eg. Concrete silo bases) In the case of tanks, troughs etc. simply putting some water back in will provide adequate hydration. Even 20 litres of water added to an empty tank with lid replaced will provide a good humid environment to hasten crystal growth.

Tip: On a sunny or hot outside wall, draping a wet bag over your work will help accelerate crystal growth.

When can I replace the water?

If working on the inside of the tank, you will need to wait for the product to have an initial set. Times will vary with temperature however 4 hours is usually adequate. We suggest that you don’t focus a pressure pump stream on your new work in the 1st day as it may wash it off. Eg . Let the water trickle in.

Coverage

1 Kilogram will treat 4.5 metres of crack or 10m/2 of porous surface.