A. Outgassing:

Bubbles may appear in the coating surface after a 100% solids coating is applied to a porous concrete surface. This condition is created when the coating begins its exotherm, or curing action. The coating increases in temperature, causing the trapped air in the concrete to also heat up and expand, thereby creating bubbles.

1. To avoid the "out-gassing" problem, seal or prime the porous concrete with Rock-Tred’s Clear AGUA-ROCK 52% Solids (a two-component, water-induced epoxy coating, applied at the rate of 250 square feet per gallon). Rock-Tred’s PENETRED or AGUA-CINCO can be also be used.

B. Air flow over two-component coatings:

Excessive air movement through open doorways, from HVAC or other sources, may cause the surface to dry too rapidly or form a "skin," preventing trapped air from being released from the coating.

1. To avoid this condition, turn HVAC blowers off (if possible) or at least direct the air flow away from the newly applied coating.

C. Excessive heat, i.e. air, surface and/or material temp. exceeding 80°F (26.7°C):

This condition will cause a coating to cure too quickly. Normal air in the coating cannot escape, thus it is trapped and expands into bubbles.

1. Avoid high temperature conditions whenever possible, or cool the material for several hours before applying, or apply the coating material extremely thin, i.e., greater than 200 coating square feet per gallon, and preferably with a solvent thinner (xylol/xylene) added up to 5% by volume.
2. Direct sunlight on 100% solids coatings — Direct sunlight will cause similar problems to those described above, resulting in isolated hot areas in or on the floor.
   1. Unless the direct sunlight is muted or the material is cooled or thinned, wait until the sunlight no longer shines directly on the floor.
3. Improper mixing — Too aggressive a mixing action (using a drill speed of over 600 RPM) will cause air to be entrapped in the coating.
   1. Use a 300-500 RPM slow-speed drill, with a Spiral Mixing Blade or Jiffy Mixer. Move the mixing blade in circles around the inside edge of the pail from bottom to top.
4. Roller Covers — Inexpensive, too short, too long or foam roller covers have been known to cause air to be generated into the coating, thus causing bubbles.
   1. Use a high-quality, "lint free," medium nap roller sleeve (preferably 18" on a heavy duty cage) and gently roll the 100% solids coating into place after squeegeeing. Vigorous rolling could also create bubbles.
   2. When applying a 100% solids coating at a coverage/thickness less than 75 square feet per gallon (with a notched squeegee), it is advisable to perform the final back-rolling procedure with a spiked roller.
   3. Note: All specialty equipment mentioned (and necessary), including spiked sandals (for squeegeeing and back-rolling), 18" medium long nap rollers and plastic spiked rollers are available from Rock-Tred.

A. Low Temperature:

All coverage rates are based on material application at temperatures between 70°-75°F. When the material, air or surface temperatures are lowered, the coating becomes thicker and difficult to spread at the specified rate.

1. To eliminate the problem, increase the room temperature, the floor surface temperature, or store the material at a higher temperature than that at which it will be applied. The addition of 5% thinner (xylol/xylene) will substantially improve the coverage rate, but will lengthen the "set" time; as will a lower temperature.
2. Reduced coverage created by too soft a rubber squeegee and/or not enought pressure applied by the individual doing the squeegeeing —
   1. Monitor the coverage rate achieved by the squeegee person to determine if the problem is in the stiffness of the squeegee or the pressure being applied. Adjust accordingly.

A. Excessive humidity in the area where the clear AGUA-ROCK is applied:

1. Do not apply the AGUA-ROCK when the humidity level exceeds 70%.
2. Use industrial fans to increase air circulation. Do not blow air directly on the coating.

B. Excessive moisture in/on the concrete surface, i.e., puddles of water not squeegeed or vacuumed thouroughly from the surface during floor preparation:

1. Eliminate all surface or standing water.

C. Insufficient mixing:

1. Thoroughly mix according to Application Instructions for 2 to 3 minutes (no longer).

D. Coverages Excesses — Too little or too much material applied:

1. Monitor coverage rates to stay within the prescribed specification, i.e., 200 to 300 square feet per gallon. Do not allow Clear AGUA-ROCK to puddle in spalls, joints or cracks, etc. Use a "long nap" roller sleeve to apply Clear AGUA-ROCK
2. If too much material is applied, it will not cure clear and may exhibit cream colored or whitish blotches. These will cure hard and stay whitish if left alone.
3. If too little material is applied, a thorough seal of the porosity in the concrete surface will not be achieved and further top coating may experience out-gassing.

E. Timing of an overcoat (topcoat):

1. Do not apply an additional coat of any 100% solids product on top of a Clear AGUA-ROCK application within less than 8 hours (at 70°F and less than 70% humidity). If the temperature is less than 70°F, allow a longer period of cure at 70°/70 RH. AGUA-ROCK can be applied to itself in 4 hours.
2. A topcoat must be applied within 36 hours — unless the Clear AGUA-ROCK application is further prepared by as described in Repair Method part VI...

A. A "gooey" mess:

No catalyst. This occurs when the mixing person completely forgets to add the Hardener to the Resin prior to mixing.

1. These are two component materials. When there are absolutely no signs of the coating hardening, count the resin and hardener used — there will be a discrepancy.

B. Tacky or sticky spots (in an otherwise cured coating):

1. Insufficient mixing. Hardener and Resin are not mixed according to prescribed methods or ratios.
2. This can also take place when a mixing pail is placed upside down onto a floor surface, allowing it to completely empty. Never allow this procedure to happen as there may be unmixed resins remaining on the bottom or sides of the pail.

C. Soft, but uniform surface:

Normally the result of a cold temperature application or an improper ratio of Hardener to Resin.

1. Elevate the temperature of the floor surface or the air. You will get a good cure if the mixtures is the correct ratio.
2. Double check for proper mixing ratio, if not mixing as packaged.

A. Silicone contaminants:

Any residual silicone deposited onto the floor surface resulting from a manufacturing or waterproofing process can cause the problems listed above.

1. To avoid this problem, be familiar with in-plant operations and when in doubt, test areas (See section C below) prior to a coating application.
2. Prepare the floor surface by removing the silicone contaminant with the recommended chemical solvent or stripping agent. Shot-blasting will not completely remove surface contaminants.

B. Oil/grease contaminants:

Any petroleum-based lubricant/product can cause a coating to have the above flaws and be improperly bonded.

1. Thoroughly remove all petroleum-based contaminants with a solvent degreaser and/or a caustic/alkaline cleaner, preferably followed by a light acid etching for neutralization, followed by a neutral pH detergent. Always prime with Clear AGUA-ROCK when contaminants are present.

C. Animal fats, vegetable oils, and or all food products or by-product spillages:

All of these contaminants will cause surface problems.

1. Where food products and/or by-products come in contact with the concrete floor surface, it is highly advisable to further prepare the concrete floor surface using the method recommended in section B. 1 above.
2. Note: Following a thorough chemical cleaning with caustic, acid and detergent, test the concrete surface for contamination from an oily substance by sprinkling with water. If the water beads up, steam clean or use a propane flame torch to bring the contaminant to the surface and chemically clean again. Using a hot water pressure washer for flushing before and after each separate cleaning process will speed up and improve the job.

A. Inadequate cleaning/preparation of the surface to which the coating was applied:

No coating will adhere to a contaminated surface — no matter how expensive the coating is.

1. Beyond providing a suitable profile for adhesion (shot-blasting or acid etching), test for remaining contaminants, especially if they were present prior to the creation of the surface profile. (See section V.B.1 above)

B. When a primer is not used:

Loss of adhesion can occur.

1. Use Clear AGUA-ROCK as a primer at 200 to 300 square feet per gallon or CHEM-ROCK Polyamide Primer (100% solids) at 200 square feet per gallon.

C. Improper or inadequate acid etching:

As previously discussed, an adequate profile (i.e., concrete with the uniform feel of medium to coarse sandpaper) is required. Without the porosity created by an adequate profile, a mechanical bond of the coating cannot be achieved. (See ICRI-CS ---- surface profile.)

1. If acid is used, a hydrochloric acid solution (HCl, often sold as "muriatic acid") is advised. Uniformly spread the acid so that no one area is etched deeper than another. In food and exposed steel facilities, we recommend the use of Rock-Tred’s ETCHER because it produces less fumes. All acid etched areas should be thoroughly flushed with clean, clear water, followed by the scrubbing of the entire surface with a dilute, neutral pH detergent (i.e., Rock-Tred's ROCK POWER), followed by an additional thorough flushing with water and dry vacuuming.

Note: An acid film, not flushed and neutralized, will also cause definite adhesion problems. Blend acid at the rate of 2 parts clean water to 1 part commercial grade acid; or 1 gallon hot water to lb. of ETCHER.

D. Excessive moisture in or on the surface of the concrete:

Will cause loss of adhesion.

1. If moisture is in the concrete and it is sealed with a non-breathing coating (i.e., 100% solids), warmer temperatures will bring it (the moisture) to the surface beneath the coating, where it vaporizes, causing pressure against, and therefore blisters in, the surface coating. Oftentimes these blisters will "grow" as the moisture and the vapor tend to accumulate beneath the surface of the coating. This condition can be verified by simply breaking a blister to determine if moisture is trapped beneath it.
   1. Note: 100% Solids coatings should only be applied to on-grade or below-grade concrete floors that have a heavy plastic "moisture barrier" beneath them, and have been tested for moisture content..
2. Use a moisture meter to test for moisture content prior to application or tape down several 36" x 36" square areas of 4-6 mil clear plastic for 72 hours, periodically checking for moisture accumulation on the underside of the taped down plastic. If moisture does form on the plastic, only coat with a breathable material.

E. Inter-coat adhesion:

Improperly prepared previously applied coatings will definitely lead to inter-coat delamination. Always test for compatibility/adhesion.

1. Although acid cannot be used to etch or initially prepare an old coating surface, it must be used for neutralization if a liquid caustic cleaning process is employed, followed by a neutral pH detergent wash and flush.
2. Should there be any gloss whatsoever exhibited by the surface to be coated, it should be thoroughly abraded with a medium to coarse sanding, the dust completely removed, and the surface "tack-ragged" or wiped with a strong solvent solution, i.e., xylene, prior to the application of a new coating. An alternative to sanding would be a "brush blast" with a shot-blasting machine.
3. "Open" re-coat times are when the previous epoxy coating has set hard enough to walk on and ends following a maximum 48-hour window.

A. Poor ventilation of a 100% solids coating that has been heavily cut with solvent:

The solvent becomes trapped in the coating and may affect gloss.

1. Uniform exhaust ventilation/air flow is always recommended.

B. Excessive humidity (above 70%):

This may cause low gloss.

1. Dehumidify, air condition or wait for less humid weather.

C. Cold temperature of either the surface, air or material:

This will cause low gloss.

1. As recommended before, eliminate one or all of the above.

D. Improper mixing:

Too short of a mixing time, lack of a thorough mixing, et al, can be responsible for low gloss and softness problems as discussed earlier.

1. Excessively high humidity and/or cold temperatures can or will potentially cause a "blush" which will exhibit itself as either a dull finish or a very slight "greasy" finish over a hardened, cured two-component epoxy coating/floor.

A. Improper mixing/blending of all pigments within the product:

When pigment has settled to the bottom of the pail due to product age, a thorough blending of the (Pigmented) Resin component, prior to the addition of the Hardener component, becomes extremely important.

1. A 3 to 5 minute mixing of the Resin is normally sufficient to eliminate this problem. Then add the Hardener, and mix the combined components for a minimum of three (3) minutes.

B. Slight variations of color from batch to batch:

1. Checking batch numbers prior to use and bunching all material from a single batch together is advisable. When coating a large floor area, always use expansion joints whenever possible to terminate a Unit of pigmented epoxy coating; therefore, should the next Unit be from a different batch, it will not be as obvious if it terminates at the other side of the same expansion joint.

C. Exposure of a cured coating to interior sunlight:

This exposure over a long period of time can cause slight discoloration or fading.

1. Should the problem be foreseeable, use colors that are less subject to ultraviolet light or top coat with a more UV stable product to lessen the problem.

D. Spotting or discoloration of a cured pigmented coating:

This can be caused by chemical attack.

1. Before installing a coating, determine its resistance to the chemical to which it will be exposed.

E. Improper backrolling:

A lack of consistency will cause color variations.

1. Be sure there is a uniform time consistency and technique to the mixing, squeegeeing and backrolling of all pigmented two-component materials applied to a given floor surface.

A. Excess thinner:

If solvent is added to the coating and the coating is applied too thick, this may cause wrinkling, or, at the very least, a dull or soft film surface.

1. When applying a thick coating for the purpose of achieving greater mil thickness and/or filling spalls, voids or rough areas, use minimal or, preferably, no solvent thinner.

B. Solvent-thinned epoxy over an unkonwn previous paint:

Solvent thinner may attack the base paint, causing it to lift and thereby wrinkling the top surface.

1. Always check for compatibility and use the least amount of solvent thinner possible.

C. Cold concrete surface temperatures:

This can cause a 100% solids coating to wrinkle or contract during the curing cycle.

1. When the concrete floor surface is below 50°F, do not coat it.

A. Improper mixing ratios or insufficient blending of hardener and resin:

This will cause a soft coating throughout that will result in premature wear.

1. Be sure that your ratios are correct (if not using prepackaged units) and that the Hardener and Resin are thoroughly blended together, as previously recommended.

B. Improper maintenance:

Poor floor care can cause premature wearing of the coating, especially in warehouse or production areas where there is the dragging of wood pallets with nails protruding.

1. Set up a proper maintenance program, including the training of fork lift or pallet jack operators. (See Rock-Tred’s Maintenance of Floors & Walls.)

C. Sub-standard or soft concrete:

This condition can cause poor performance at best, or complete loss of adhesion.

1. Check for concrete softness with a penknife. If you are able to carve your initials by hand with a penknife, you have bad/soft concrete and potential problems.

A. Lint from a roller sleeve:

1. Improve the quality of your roller.

B. Dust, dirt or blasting shot not removed from the floor surface before coating.

C. Poorly mixed dry additive, i.e., aggregate or Thixo, etc.

D. Dirty equipment used in mixing, or applying.

E. Product beyond shelf life and/or poorly mixed.

F. Unblended product having been frozen in shipment or storage.

1. Thaw out at a minimum 85°F for 72 hours; thoroughly blend each component separately before mixing together.

A. Thoroughly abrade bubbled floor area with medium grit sandpaper on a rotary disc scrubber (or medium to coarse stones on a terrazzo grinder); completely remove all dust; "tack-rag" or wipe the sanded surface with xylene/xylol; and recoat at a maximum rate of 150 square feet per gallon if less than 30 days old.

B. Large bubbles many require hand grinding before sanding — always feather edge all imperfections.

C. Large areas may also require a tightly applied re-prime application of Clear AGUA-ROCK.

A. Test the problem area with a water moistened rag to determine if an additional coat will "wet out" the cloudiness. If successful, recoat.

B. If cloudiness cannot be "wet out" by a top coat, shot-blast to remove and recoat according to specifications. If surface is hard, and the next coat is to be pigmented, go ahead and coat.

A. If floor surface is "gooey" and it is determined that a Hardener was not added, use long-handled drywall scraper knives or a "Scrape-Away" tool on a rotary scrubber to remove all uncured coating.

B. Follow scraper removal of the "gooey" epoxy with a strong safety solvent scrub high in KB’s; vacuum up residue; shot-blast the area again or chemically clean to bare concrete.

C. If uncured coating is only tacky or sticky in spots, identify all locations and mark them. You only want to repair once. Diamond hand grind and/or scrape and solvent clean as above; patch, apply the coating on the spots. Remember that patches will never blend in and, therefore, it may be best to completely recoat the entire floor.

D. If the floor surface exhibits signs of having partially cured uniformly, but is still soft, it is probably not cured — allow additional time.

A. Thoroughly sand/grind coated floor surface as recommended above in Section (A.); vacuum/clean and "tack-rag" prior to recoating. Only apply one Unit to monitor results; backroll as late as possible to minimize a repeat of the "fish-eye" occurrence.

A. If in isolated areas, key the perimeter with a sharp knife or portable saw at 1/16", remove all coating in the interior of the key to bare concrete; repair by following the original specifications.

A. If there is a "blush" or "greasy" film on the floor surface, scrub with a strong neutral pH detergent or wipe with a strong solvent (i.e., xylene/xylol, etc.). If recoat time has elapsed, thoroughly sand/grind the floor, clean off dust and "tack-rag" before recoating.

A. Thoroughly sand and/or grind to a completely smooth surface; vacuum/clean and remove all dust; "tack-rag" with strong solvent (i.e., xylene/xylol, etc.), elevate surface temperature to acceptability and recoat.

Note: If there is moisture vapor from within the concrete, forcing the coating to "blister", it is usually caused by a lack of a moisture barrier beneath the concrete slab. Check the "blisters" for moisture content. If this is the case, (and there is moisture), contact Rock-Tred’s technical staff for a recommendation or remove all of the coating to bare concrete and seal with one or two coats of Clear AGUA-ROCK.