Durabak

Nov. 01, 2005 By ORC STAFF

DurabakCote-L Distribution Company's Durabak® is an easy-to-apply product that results in a good-looking, durable, chemical-resistant, flame-resistant, UV-resistant, non-slip finish. Durabak is composed of a polyurethane base with ground up recycled tires suspended in it for "grit" and non-skid properties.

Available in twelve colors, I received a gallon of dark gray Durabak via Off-Road.com and courtesy of Cote-L Distribution Company. This color turned out to be almost a perfect match for "Samurai Interior Gray".

Durabak is available in quarts or gallons at approximately $99.00 US per gallon (the price can vary to as much as $140.00 US depending on the quantity ordered and the color). Its price is comparable to most other automotive paints and far less than that of shop-applied linings such as Rhino Liner. It has the added benefit of being easily applied by the do-it-yourselfer, thus removing the inconvenience of having to transport your rig to a shop or be without your daily driver waiting for a shop to apply a liner. One gallon covers approximately 60 square feet.

It was my objective to coat almost the entire interior of Project Suzushi and thus be able to do away with the carpet. I wanted something much easier to clean that would still have some sound deadening characteristics. I easily accomplished coating all the areas I wanted done with the gallon of Durabak I received. Two coats were applied to all surfaces; three to the front and rear floor pans and the rear bed area.

How supplied

Durabak is shipped in a one-gallon paint can and includes a special roller to ensure that the tire particles are properly distributed during application. It can also be sprayed (thinned about 10% with Xylene) with a Schutz (undercoating) gun or brushed (using a natural bristle brush, as I did). The gallon can comes with lid-retention clips installed and an air-tight seal to prevent it curing in the can. It's a bit difficult to open as a result, but better that than have it arrive as a solid lump of polyurethane and rubber bits! It has an un-opened shelf life of approximately one year. As I received mine just before El Ni?o hit here in California, it ended up sitting on my shelf for about four months, while I waited for a few sunny days. Counting transit time from Cote-L to Off-Road.com and from Off-Road.com to me, that meant it had been sitting for somewhere in the neighborhood of 5-6 months when I used it. It was absolutely fine in all respects.

Preparation

Preparation of the surface for coating is easy. Make sure it's clean and free of rust, scale or loose paint, then sand the surface (I used 60-grit sandpaper) to give it some "tooth". Vacuum up the dust and loose particles. Once that's complete, follow Cote-L's guidelines and clean the surface thoroughly with rags soaked in Xylene, which will evaporate leaving no residue, unlike thinners such as lacquer thinner. Xylene is also recommended for thinning Durabak, for cleaning up drips and runs during application and to clean up tools when you're done. I recommend you clean up promptly, as the applied coating is extremely hard to remove from surfaces, tools or hands when cured.

Application

Application of the coating is not difficult, but does require a different technique (because of the suspended particles of recycled tires) than most paints. For my brushed-on finish on Suzushi's interior, I found that keeping a well-loaded brush with a minimum of "brush-out" was best. Second and subsequent coats should be applied after the first coat is surface-dry and in a direction 90? to the direction of application of the first coat for best results. Although it's more difficult to tell than with paints -- because of the grit particles suspended in the Durabak -- it's my impression that it leveled well, as I have no visible brush marks in my finish.

Durabak cures through a combination of heat and humidity. As a result, cure time is faster on warm, humid days, however, Durabak can be applied at any temperature above freezing. It's surface-dry in just a couple of hours, useable after an overnight cure time, and fully cured in about 3-4 days, depending on temperature and humidity. An accelerator is available at $3.20/packet if shorter cure times are required or if Durabak will be applied at very low ambient temperatures. One packet of accelerator will treat one quart (four packets/gallon).

Pot life of Durabak is rated at 3 hours, depending on temperature and humidity, but I was able to work with it for much longer than that. It should be stirred thoroughly and often while being applied (I'd recommend using a stirring bit chucked into a drill). If you keep an eye on its consistency while you're applying it and add a little Xylene (well-mixed in!) to it every time you notice it starting to get a bit thick, you should have no problems. I first noticed it getting thicker at about 4 hours working time (60?F and high humidity due to recent rains) and added about 2-3 ounces of Xylene until it appeared to be the same consistency as it was when I opened the can. Thereafter I added about an ounce to two ounces (no more than two) of Xylene every hour until I was finished, mixing well each time. My total working time was about 10 hours for a temperature range that varied between a low of around 50?F to a high of about 65?F, but had I had any Durabak left at that point (or anything left to coat!), I'm sure I could have continued for a while more.

Safety

As this was a rather hot topic lately on Off-Road.com's Suzuki Mailing List, I called Cote-L to inquire about Durabak's safety for interior automotive use. I had a pleasant conversation with Jake Ickowicz, President of Cote-L. He was kind enough to provide me with the following information about the properties of Durabak:

ASTM E84-91A
(Flame Spread and Smoke Development)
Flame Spread: 5
Smoke Development: 10
ASTM E662
(Smoke Density Chamber Test)
Non-flaming mode:
Durabak: 1, Maximum allowed: 100
Flaming mode:
Durabak: 116, Maximum allowed: 200
ASTM E162
(Surface Flammability)
4 minute exposure: 0
All flame was limited to the area of flame application of the test flame.
ASTM D1894-93 Static Coefficient of Friction: .96
Dynamic Coefficient of Friction: .92
Motor Vehicle Safety Standard 302
(Flammability of Interior Materials)
Durabak exceeds the standard by not burning or transmitting a flame front at greater than 4"/minute over a 10" distance.

Durabak is rated "Class A" in the interior wall and ceiling finish category for buildings, the highest available rating.

Results

In a word: excellent!

Close up of DurabakThe finish is glossy, opaque and seamless and shows no brush marks (no mean feat when it's me doing the painting) as you can see in the close-up at left. The suspended rubber particles distribute well, resulting in what looks sort of like a "sand" finish (only coarser) that's resilient and tough.

Objects with any significant surface area placed in the rear of the truck stay right where they're placed without sliding around and it's taken knocks and bumps well, with no visible signs of damage whatsoever. While a Durabak lining is no substitute for properly securing gear for the trail, it certainly prevents things from shifting around while running around town.

Although I have not had to test this aspect of it yet, Durabak can be cut with a sharp knife and peeled or scraped away for modifications to your rig. It will also adhere to itself, so any tears or damage should be repairable by simply reapplying Durabak at the point of damage.

Cleaning is a snap. Soap and water and a brush work loose whatever is on it. Then simply rinse. So far mine has had sand, pine needles and sap, and clay and earth from off-roading on it. All have cleaned up easily.

My new lining has been in place for over a month now (at the end of April, 1998), through snow, rain, mud and hot dry weather and looks as good as new. Even the door sills show no signs of scuffing, much less any sort of wear. I'd highly recommend this coating for anyone wanting a good looking, durable lining that can be home applied and doesn't cost a fortune. As a matter of fact, I'm already thinking of other places I could apply it: A permanent "bra" for the front end? A full frame coating for any sort of frame-off restore? Wheel-wells? Heck, at least two trucks have had their bodies completely coated in it already  instead of paint!

--Scott Gomez


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