Series 257

ExcellaThane SS

Generic Type

Modified Aliphatic Polyaspartic

Common Usage

A slower setting Polyaspartic floor coating, offering longer working time and lower viscosity. Series 257 minimizes the potential for lap marks and roller lines when used in large flooring applications. It can be used as a two coat thin-film system or as a clear or pigmented finish coat over systems built using epoxy or polyurethane modified concrete floor toppings that have been fully broadcast with aggregate, colored quartz or colored flake. Series 257 will provide protection against impact, abrasion and mild chemicals, has excellent gloss and color retention, and resistance to yellowing. This low VOC, 100% solids urethane exhibits low odor characteristics allowing for use near occupied spaces.

Special Qualifications

Series 257 was tested in accordance with, and passed, the California Dept. of Public Health (CDPH) Standard Method v1.2 and meets the requirements of LEED v4.1 Low-Emitting Materials, Collaborative for High Performance Schools-Paints & Coatings, Living Building Challenge Materials Petal 10, and WELL Building Standard v2 X06 VOC Restrictions.

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Series 247, 248, 257. Note: Before applying Series 247/248 over coatings with a smooth, glossy surface, thoroughly scarify the Series 257 using a power sander and 100 grit sandpaper, No. 60 mesh sanding screen or a coarse stripping pad to eliminate surface tension. Failing to uniformly degloss the entire surface or thoroughly clean all surface contamination may lead to fisheyes and/or poor adhesion. Sanding or scarification is not required when topcoating textured coatings (i.e. aggregate or colored quartz broadcast to refusal) with Series 247/248 if maximum recoat time of the previous coating is met.

Recommended DFT

Primer: 6.0 to 12.0 mils (150-305 microns) per coat.
Broadcast: 1/16" to 1/8" (Double broadcast or slurry broadcast required to achieve 1/8")
Grout coat: 8.0 to 16.0 mils (203 to 406 microns)
Intermediate or Topcoat: 8.0 to 16.0 mils (203 to 406 microns)
Note: Do not exceed 20 mils (500 microns) dry film thickness.


Gloss. The texture of the finished surface will depend on the film thickness and number of coats applied. Note: Application as a clear topcoat may lead to a cloudy appearance if the product is overworked, applied too thick, or applied too far into its pot life. This product has a short working time. Caution should be taken to apply the material immediately after mixing and to not overwork the product when rolling.


Series 215, or Series 201, 256 or 257 mixed with select aggregate fillers may be used for small patches or crack repairs. Certain high-early strength, cementious repair mortars are also acceptable for deeper filling and patching. For more extensive repairs and additional information, contact your Tnemec representative or Tnemec Technical Services.

Curing Time

Temperature To Topcoat Light Traffic Place in Service
75°F (24°C) & 50% R.H. 3 to 5 hours minimum, 48 hours maximum• 6 to 8 hours• 12 to 24 hours•

•For applications at 75°F and 50% relative humidity, if more than 48 hours has elapsed between coats of Series 257, the surface must be mechanically abraded before recoating. For applications between 70% and 80% relative humidity, if more than 36 hours has elapsed between coats of Series 257, the surface must be mechanically abraded before recoating. Curing time varies with surface temperature, air movement, humidity and film thickness. Relative humidity greatly impacts the working time, cure speed and recoat window of Series 257. Working time and the recoat time will decrease and cure rates increase when applying in higher humidity conditions. Do not apply if relative humidity is greater than 80%.

Theoretical Coverage

1,604 mil sq ft/gal (39.4 m²/L at 25 microns). See APPLICATION for coverage rates.

Volume Solids

100% (mixed)

Volatile Organic Compounds

Unthinned: 0.04 lbs/gallon (4 grams/litre)
Thinned 5% (No. 72 Thinner): 0.42 lbs/gallon (51 grams/litre)

Number of Components

Liquids—Two: Part A and Part B (1.5 parts A to 1 part B by volume)
Optional Field Colorant: Series 821 is sold separately and available in pint containers in 16 standard StrataShield colors and limited custom colors.


Unthinned: 0.01 lbs/gallon solids
Thinned 5% (No. 72 Thinner): 0.01 lbs/gallon solid


Series 222, 224, 233, 237, 238, 256, 257. Note: If Series 222, 224, 233, 237 or 238 is used as an intermediate coat, aggregate, colored quartz, or decorative flake is typically broadcast to refusal into the intermediate coat prior to topcoating with 257.


Self-priming or Series 241, 242, 245. Note: When applying over standard epoxies or epoxy primers the epoxy is typically fully broadcast with aggregate, colored quartz or colored flake or mechanically abraded using 60 grit sandpaper or coarser. Note: When building systems using 222, 224, 233, 237, 238, 241, 242 and 245 refer to applicable product data sheet for appropriate primer/intermediate selection.

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