common problems with epoxy coatings and

7/28/2019 Common Problems With Epoxy Coatings And

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Bubbles in Epoxy Coatings:

If you have bubbles, the only way to repair the damage is to abrade the area thoroughly withmedium grit sandpaper and a rotary disc scrubber. Once you have abrade the area, you need tovacuum/clean off dust, you may use a tack rag to make sure you have removed all the debris.You also wiped the area with xylene or a strong solvent. Once the area has completely dried,recoat the area. Make sure the area has dried or adhesion problem may occur.

For large bubbles, those bigger than a dime, may require hand grinding before sanding and withall bubbles, always feather edge all imperfections.

Note: If you have a moisture problem that is causing the coating to bubble, and there is nomoisture barrier beneath the concrete slab, there is no method to eliminate the problem. It isstrongly recommend that you strip all of the coating to bare concrete and then seal the entire areawith several coats of an epoxy tolerant moisture primer such as PioneerPro GreatFloor 100Moisture Tolerant Epoxy.

Shortage on Coverage:

The majority of manufacturers have strict coverage rates. Therefore, if the area you want to coatis larger than the published coverage rate, always purchase another kit, or gallon. Do not try to“Stretch it.” However, there are times when you have followed all directions and still come up withless than what was specified.

One reason for shortage could be attributed to low temperatures. This is because coverage ratesof all manufacturers are based upon applying the epoxy coating with temperatures between 70°-75° F. When the air temperature or surface temperatures are below 70oF, the epoxy coating willbecome thicker, making it very difficult to spread. To help eliminate this problem you can raise the

room temperature or the floor surface temperature so that it is between 70o

F-75o

F. Some expertsalso recommend that you cut the epoxy with a 5% recommended thinner. However, we do notrecommend this as it will also decrease the "set" time and can cause other more seriousproblems.

Another cause of shortage is caused by application technique, where the epoxy is applied with notenough pressure to the roller. For this reason, it is vital to monitor your coverage rate and to



adjust how you are applying your coat accordingly.

After 24-Hour Cure, the Coating is Still Soft:

If after the sufficient amount of curing time has passed, your epoxy coating still has not hardened,or has a tacky feel, the problem more than likely is that no or inadequate reaction took place.Unfortunately, this happened because the Part B was either not added to the Part A prior tomixing, or the right proportions were not mixed together. If you go back and count the number of part A's and B's used more than likely you will find the discrepancy.

If the majority of your floor has cured, but you still have tacky or sticky areas, this is caused by

insufficient mixing or if part A and B were not mixed according to the manufacturer's instructions.Tacky areas can also be due if someone took and place the mixing pail upside-down onto a floor surface, so that you can use every drop. As tempting as this may be to do---DO NOT DO THIS!When you place the mixing pail upside down and allow all the epoxy mixture to drain out theremay be unmixed or unblended resins that are on the sides of the pail that will drip onto the floor.

If the surface however, is soft and not uniformed, this is usually due to application in coldtemperatures. However, in some instances, it is due to an improper ratio of Parts A to B.

For all of these problems, test the problem area to ensure that the epoxy floor sealer/finish is notwet or tacky to the touch. As long as the sealer/finish is not wet, then it can be top coated.However, if this does not repair the problem, then the area will have to be shot-blast, cleaned,then recoat according to the manufacturer’s instructions.

Imperfections and Fish Eyes:

Fish eyes are imperfections in the surface of the epoxy coating, which resemble the fish eyes.

Deposits of residual silicone on the surface of the floor cause this type of imperfection. To avoidthis type of imperfection, make sure that you properly prepare the concrete surface with therecommended solvent or stripping agent to remove any silicone contaminants.

Any petroleum-based lubricant as well as any form of oil or grease including that from foodproducts will cause surface problems, which will cause the epoxy coating to improperly bond. Toprevent any problems make sure that you remove all petroleum-based contaminants with an Oil &



Grease Emulsifier, followed by a thorough chemical cleaning with caustic, acid, and detergent,test the concrete surface for contamination from an oily substrate by sprinkling with water. If itbeads up, steam clean or torch to bring the contaminant to the surface, and chemically cleanagain.

The only way to repair fisheyes or other imperfections caused by oil or grease residue is tothoroughly sand the surface of the area, then following the steps, thoroughly clean, the areaagain, making sure that you remove the silicon, oil or grease. Before you recoat the area, makesure that you go back over the area with a vacuum or clean the area with a tack rag to ensure thatyou remove all debris. Before you recoat your entire floor, only apply one unit at a time to monitor to see if the fish eyes reoccurrence.

Poor Adhesion, Peeling, or Flaking:

Poor adhesion, peeling, and flaking are condition of delamination. Many times, inadequatecleaning or preparation of the concrete surface prior to applying the epoxy coating causesdelaminating.

Another cause of poor adhesion is excessive moisture, which will cause blisters in the epoxysurface that later peel away.

Whether the cause was due poor preparation or moisture, the only way to correct poor adhesion is

to sand blast the surface, removing all the flaking coating. Many times, when left alone or ignored,blisters will expand or grow, as the more moisture accumulates underneath the surface of theepoxy. For this reason, it is important to note that if you are applying 100% solid epoxies, theyshould only be applied on-grade concrete floors that have a Visqueen moisture barrier or another reputable poly-sheeting barrier beneath them. In addition, you can use a moisture meter to testfor moisture content prior to application. A simple test that is easy to perform is to tape down a 3square foot area of 4-6 mil plastic for a minimum of 72 hours, then check underneath the plasticfor any accumulation of moisture.

Inter-coat delamination is another form of poor adhesion. Applying epoxy coating over apreviously applied coating often causes this. It is important, to always take time to test for compatibility/adhesion if you plan to reapply any coating.

In addition, if the surface that is to be coated shows any gloss whatsoever, the surface should beabraded using a medium to coarse sandpaper. Make sure that you remove any dust from thesurface with a tack ragged or wipe the surface with a rag and strong such as xylene, prior to the



applying the new coating.

If you have an adhesion problem that is throughout your entire floor, it is best that you shot blast

the entire floor to the bare concrete, then following the instructions on the coating product, recoatthe floor. Make sure however, that you correct any problems due to moisture.

If the problem is isolated, then you can key the perimeter with a sharp utility knife, and thenremove all of the coating to the bare concrete from inside the key area. Then repair the area,making sure that you follow the coating instructions as specified.

After 24-Hour of Curing the Finish is Still Dull or Low-Gloss:

A dull finish after more than 24 hours can be due to several reasons. The most common reasonhowever is from poor ventilation. When you apply 100% solids epoxy the solvent can becometrapped within the coating, causing the finish to dull. This is why having proper ventilation/air flowis strongly recommended.

The second most common cause of a dull finish is excessive humidity, which is humidity of above60%. For this reason, epoxy coating should not be a task performed on rainy days. It is alwaysbetter to wait for less humid weather. To help reduce the amount of humidity in the room, you canoperate a dehumidifier or run your air condition.

Other causes of a dull finish are improper mixing and/or applying the epoxy coating when either the air temperature or surface temperature of the concrete is cold. It is important to note thatexcessive humidity that which is above 60% and/or cold temperatures can cause blushing. This isa dull finish or a very slight "oily" finish over a hardened, cured 100% solids epoxy coating/floor.

If your concrete coating has blush or an oily film, you can scrub the surface using a strong neutral

pH detergent or sponge clean using a solvent such as xylene. If this does not correct theproblem, or if the recoat time has elapsed, then you will need to thoroughly sand or grind theconcrete flooring, followed by removing the dust with a tack rag before you recoat your flooring.

Lumps, Bumps or Globs in the Surface:



Sometimes no matter how well you sand, rinse, and clean the concrete surface, you will stilldiscover lumps, bumps, or globs in the dried surface. These lumps, bumps, and globs of oftenlumps of 100% solids epoxy caused by poor mixing or from using dirty equipment when mixing or

applying the epoxy coating. Lumps can also come from lint from the roller sleeve that you use,especially if you opt to purchase less expensive rollers. There is nothing wrong with trying to savemoney, however, it’s always best to purchase quality rollers when apply epoxy. Another areawhere you do not want to cut coast is purchasing or using epoxy products that have expired, asthey will usually lump.

Another cause of lumping is when part A has been frozen. If you live in a cold climate area, makesure that part A is completely thawed at 85° F for 72 hours, and then you want to blend itthoroughly before using.

If you have bumps, lumps, or globs in your epoxy coating, to correct these imperfections is to sandor grind out the imperfections and then recoat the areas.

Wrinkles:

Wrinkles are rare; however, they do appear when applying 100% solids epoxy coating. The maincauses of wrinkles are due to excessive thinning. Excessive thinning is usually caused by solvent

added to the coating. However, wrinkles can appear when the coating is applied too thick, or when it has a soft film surface. If you need to apply a thick coating to achieve a higher milthickness in order to fill in spalls, voids, or rough areas, it is strongly suggested that you use littleto no solvent thinner.

Another cause of wrinkling is applying the epoxy coating to a cold concrete surface. This is whenthe surface temperature is below 50°F.

To repair your wrinkling problem, thoroughly sand the area completely smooth, followed byvacuuming to remove all dust, and then go over the area with a tack rag and solvent such asxylene. Allow to dry then recoat.

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