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The two best ways to prepare concrete and steel are by shot blasting, and pressure washing. Pressure washing works well on almost any surface (wood, metal, concrete, PVC, plastics, and most coated materials). This method works in very tight, hard to reach places that even small grinders cannot get into.
Unless the surface of the material to be coated is highly sealed like teak wood, stainless steel, or a high grade of aluminum, or unless water cannot be used to prep a surface for some safety reason, a Clorox rinse (One cup Clorox to a gallon of water in a garden sprayer) keeping the surface to be coated wet for at least 20 minutes, followed by a horizontal/vertical pressure wash at 2500 psi using a 15 degree nozzle, keeping the nozzle roughly 4 inches from the surface of the substrate, will remove and clean at least 95% of all dirt, grease, oil, and grime from the surface of the substrate to be coated. When the surface is clean and dry, then perform the 2 inch patch test. Click here to review the 2 inch patch test. For wood or soft surface material, the nozzle will need to be just far enough away from the surface to clean it, but not to destroy it. On wood, soft foam, or other materials you can do more damage than good by being too close to the surface with the nozzle. With wood, the nozzle can strip away the wood pulp and only leave the woody fibers. This will cause the project to use maybe twice the material than is typically required, to cover the fiber of the wood. On wood, it is sometimes necessary to do a deep cleaning of the wood pulp, because it is dry rotted down into the wood. In these cases, for example if the wood is 3 inch by ½” tongue and grove, and you have to remove a ¼” of pulp, it is time to replace the wood. If you have to remove 1/16” to 1/8” to get to good wood, now use a belt sander and remove the fiber down to the good wood, then pressure wash to remove all of the sanding dust. When the wood is clean and dry, perform a 2 inch patch test.
Application dry mill thickness vs weight applied to floor coating
Before talking about dry mil coating thickness, let us talk about per cent of solids in any liquid coating.
When applying products that are 100% solids if you put down 10 wet mils you will get roughly 10 dry mils. If you put down 15 wet mils of Durabak 18 it is going to give you roughly 10 dry mils, because Durabak 18 material is 67.7% solids, or roughly 68% solids.
Now let us also talk about application rates.
A gallon of liquid is always 128 oz of material. When that material is applied at 1 wet mil, it will cover roughly 1086 sq ft. When applied at 5 wet mils it will cover 350 sq. ft. When applied at 10 wet mils it will cover 160 sq. ft. When applied at 15 wet mils it will cover roughly 110 sq. ft. When dealing with Durabak 18 smooth the above numbers work well, if no other factors apply to the surface of the substrate. When dealing with Durabak 18 non slip, it is important to understand that there is roughly a quart of liquid take out of each can, and a quart of rubber chips are added. The rubber chips require wetting of their surfaces, so in all roughly 80 oz of the 128 oz. normally in a gallon is left to spread at 15 wet mils. So a gallon of Durabak 18 non slip will only cover roughly 65 sq. ft. per gallon.
Now let us talk about substrate surface profile.
All application rate are usually based on the ISA 120 profile. It is a standard used by most industries to determine application rates. When the surface profile varies the application rates will also. If the surface is better than a 120 profile the application rates will go up. If the surface profile is worse than 120, the application rate will go down. Concrete and wood can vary greatly, it needs to be looked at before estimating the volume of material need for a job. That is why shot-blasting concrete is such a good idea, it will take the high points off the concrete, and less material will be lost into the surface profile. Wood usually needs to be sanded to avoid this issue. For aluminum and smooth finished surfaces, roughen the surface to be coated with 80 to 120 grit sandpaper.
Open and closed cell foam have real issues with surface profile and surface porosity. In the case of wood and concrete, the dust has to be removed before the surface can be coated. That is why it is important to do the 2 inch patch test.
It is important that we talk about surface porosity
Most of the time it can be ignored, however in some cases it becomes very important, and can cause a project to use twice as much product as normal. So, surface porosity is the number of very small hole in the surface of a substrate and the diameter and depth of them. If these items are all small, you will only lose .25 to maybe 2% of the product down into the surface porosity. However if you have CDX unfinished or marine grade plywood, the % of lose can be 10 to 20% of the material, and if you combine this lost with surface profile of CDX unfinished or marine grade plywood the material filling the large holes, and the material needed to cover over or filling in the small valley on the surface of the wood can be easily 35 to 40%; This loss of covering the high points of this kind of wood cause these kinds of materials to fail. For example typically a gallon of Durabak 18 non slip will cover 65 sq.ft. at an application rate of 15 wet mils. Here you may only get 30 sq. ft per gallon to apply 15 wet mils over the top of the highest peaks in the valley of the wood.
This is why it is a good idea to belt sand rough grade woods before applying any coating to them.
However, there is a secondary issue to take care of when sanding wood; That is getting all of the dust off and out of the surface of the wood after sanding it. If the wood dust is left on the wood, the Durabak 18 will stick to the wood dust and not to the board fibers and pulp and it will release or delaminate. That is why any prep needs to have the 2 inch patch test run on it, and it is real important to do it on sanded wood.
Sometimes it is a requirement to grind concrete
When gridding is involved, remove of the dust has to happen or it will cause delamination of the Durabak 18, because the Durabak 18 will bond to the concrete dust and not to the surface profile and surface porosity of the concrete substrate. That is why any prep needs to have the 2 inch patch test run on it, and it is real important to do it on sanded wood.
Coverage of a gallon of Durabak 18:
A gallon of Durabak non-slip will cover about 60 square feet, at 15 wet mils (or 2 coats at 8 wet mils each- the recommended 2 coats). A gallon of smooth Durabak will cover 110 sq ft at 15 wet mils. Note: As a hint, a 3/8 inch nap roller cage will apply Durabak 18 smooth at roughly apply 12 to 15 wet mils naturally. A 3/16 inch lamb skin roller cage will apply Durabak 18 smooth at roughly 10 to 12 wet mils naturally.
When applying Durabak 18 non-slip the Cote-L stipple rollers will apply roughly 12 to 15 wet mils naturally. A quart of Durabak non-slip will cover 15 square feet at 15 wet mils. A standard 2 inch chip brush will apply roughly 12 to 15 wet mils. A very good horse hair or filament brush will apply Durabak 18 at about 5 to 10 wet mils, depending on how wet the brush is and if the area is back brushed. These numbers are subject to some variability due to external factors, such as the porosity of the surface. Please call us at 201-379-5366 for more input on your project. We are here to make each project simple and easy to get done.
Normal drying time vs temperature and humidity for Durabak 18:
A standard application rate for Durabak 18 material is 15 wet mils. At this applied rate and on a 70 degree F day at roughly 30 % humidity, you can expect the surface to be tack free in roughly 40 minutes and dry in 55 minutes, and ready for recoat in roughly 65 minutes. Never apply Durabak 18 at less than 8 wet mils, or it will take hours if not days to cure out. If Durabak 18 is applied at less than 8 wet mils, use spike shoes and recoat at 8 to 12 wet mils. Your drying time will come in at roughly 60 minutes. You can apply Durabak 18 at thicker application rate, but your drying time will go up. During a working day, 15 wet mils is recommended to get the most work done and to ensure the toughest material when cured out. Applying Durabak 18 at 25 to 30 wet mils should only happen when there is at least 8 hours for an area to dry and cure. Make sure the area is secured and that no one will walk over the surface until it is at least tack free. When building up layers to meet designated dry mil thickness to handle the abrasion of the traffic load, time is your enemy. The quicker you can get back onto a floor for build up the better it is for everyone. Thicker application of Durabak 18 is not recommended unless you know what you are doing and all of the conditions are just right to allow the material to dry and cure out correctly.
How atmospheric and substrate temperatures affect the project:
If the temperature drops to 55 degrees F, you can expect drying times to go up to several hours. If the temperature gets above 85 degrees, it will also slow down the drying time. Note that atmospheric temperatures maybe in the 65 to 85 degrees, but the substrates may be 10 to 20 degrees colder or hotter than atmospheric temperatures so although the air is 70 degrees F, always look at the substrate's temperature. Sometimes the application and drying times need to be adjusted for substrate conditions. You may have to start multiple areas of a project to get the job done on time. For more input and suggestions on how to work a job, call 201-379-5366 and we will support you on your project.
Dry mil thickness vs traffic abuse and loads:
In general here is a quick table addressing dry mill thickness to traffic loads
Light to moderate personal traffic: 10 dry mils
Commercial walking traffic: 20 -25 dry mils
High corner traffic: 25 -30 dry mils
3500 lbs fork truck traffic general straight path traffic: 25-35 dry mils
3500 lbs fork truck traffic around the end of shelving: 45-50 dry mils
3500 lbs fork truck traffic at loading dock area: 50-55 dry mils
3500 lbs fork truck traffic on diamond plate at loading dock area: 55-60 dry mils
6500 lbs fork truck traffic: 55-60 dry mils
10-12k lbs fork truck traffic: 65-70 dry mils
Please contact us with any questions or concerns that you may have!