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Toxics Use Reduction Institute · Surface Solutions Laboratory
 
Toxics Use Reduction Institute




Surface Solutions Laboratory

Trial Report



Trial Number 21

(Client Number 244, Project Number 1)

Trial Purpose: To re-evaluate drying times for two of the floor finishes.

Date Run: 09/13/05

Experiment Procedure:
The moisture content at the time of testing will influence results due to the hydroscopic nature of the base materials. Therefore, efforts must be taken to ensure that the moisture content and temperature remain constant during the evaluation period. Ideally, the sample floor should be kept at 65+/-1% relative humidity and 68+/-6 F.

During laboratory testing, conditions were slightly drier, 40% relative humidity, but the temperature was within the given temperature range ~70 F).

The flooring material supplied was Hardwood flooring made from Red Oak. The boards were ?? thick, 2 ?? wide and cut into 8? sections. Some pieces of the flooring had to be sanded prior to making initial thickness readings to remove residual packing tape adhesive.

Three coupons were coated with a supplied floor finish according to the manufacturers? specifications. The finish was applied using a 1? Pure Bristle 1500 paint brush. To ensure consistent coating application, the finish was leveled off using a 10 mils Precision Gage & Tool Co Dow Film Caster. A total of three coats were used for each floor finish as this was common number of coating layers suggested by the various manufacturers. One product was a two part mixture (lacquer and hardener). Three coats were applied on set of boards. The second set of boards were first coated with primer and then followed by two coats of the two part mixture.
Each coating layer was allowed to dry for 2 hours prior to the application of the next coat. Completed coupons were allowed to sit for a minimum period of 24 hours before performance evaluations were conducted.

During the sample preparation with floor finish, drying times were monitored. Observations were made after the first coat at every 10 minutes until the finish was dry to the touch. The amount of drying completed during each time interval was estimated and recorded. Subsequent coats were analyzed in the same manner. Drying times for each finish were compared to each other.

Trial Results
Observations made were based on the approximate area that looked and felt dry. 

Drying Times (minutes)      Observations % Dry  - qualitative visual assessment
First Coat                              10  20  30  40
Pro Finisher Sanding Sealer             65  85  100

Second Coat                             10  20  30  40
Pro Finisher Polyurethane               40  80 100

Third Coat                              10  20  30  40  50
Pro Finisher Polyurethane               30  40  85  95 100

The final coating dry time took longer when the Sanding Sealer was used as the base coat for the Polyurethane coating then when either product was
used alone. The third coat took 50 minutes to dry when used together. Each product only needed 10 minutes to dry when used separately.


Success Rating
A follow up test, usually based on company input.

Conclusion
When using the sealer with the polyurethane, drying times were only increased during the third coating (second coat for the polyurethane).