Industrial and Marine Synthetic Resins and Specialties
5100 Channel Avenue   Richmond CA  94804-4646
vox 1-510-237-6842   fax 1-510-232-9921
email  smi3th@smithandcompany.org

Five Year Clear Polyurethane coating system specification


     This is a moisture-sensitive system.  Do not allow moisture as liquid water to touch the surface being finished, from beginning to end of the application process and at least two days thereafter.  This includes not only rain but dew or other nighttime condensation.  Do not apply if the nighttime temperature is below 50 F.  The consequences may require stripping and starting over.  
     Five Year Clear TM polyurethane shall be applied over a properly prepared wood substrate [Other substrates are possible, as well as pigmented systems, but this specification covers only the Clear on Wood.] according to the instructions of the manufacturer.  The personnel actually applying the product shall meet with the manufacturer's representative, to discuss the instructions, after having read the instructions and before beginning the application process of any of the products.  Application without this meeting is not permitted.  
     Do not use any chemical paint strippers in the preparation of the substrate without prior review and approval of its formula by Smith & Co.


MultiWoodPrime, also known as Clear Penetrating Epoxy Sealer TM (Warm Weather Formula)
Five Year Clear Polyurethane
Five Year TM Brushing Reducer (as appropriate)
Five Year TM Spraying Reducer (as appropriate)
Five Year TM Polyurethane Flatting Concentrate (as appropriate)
Urethane Cleanup Solvent.  (as appropriate)
Cold Weather Accelerator.  (as appropriate)


The wood surface shall be mechanically shaped and all holes drilled.  Sharp corners allow the coating to be excessively thin and are a source of premature failures.  Therefore, all exterior corners shall be rounded to no less than 1/8 inch radius.  The wood shall be clean of sanding or other debris or old finishes.  Chemical strippers shall not have been used in the removal of any old finish without the prior approval of Smith & Co., as some may leave nonvolatile residues in the wood which will degrade subsequent applications.  
     Usage of Clear Penetrating Epoxy Sealer is not fully predictable as it soaks into the wood on the first application, depending on the porosity of the wood.  Thus, usage may range from 30 to 300 square feet per gallon on the first application.  The subsequent applications lie largely on the surface, and usage may be on the order of a few hundred square feet per gallon per application, with as many as needed to seal the surface porosity.  This ranges from two to five applications, typically, depending on the wood.  
     Usage of Five Year Clear Polyurethane shall be controlled, in that a 2-pint kit of Five Year Clear Polyurethane shall be applied, in as many coats as are necessary to use it up, over each 25 square feet, or a 2-quart kit over 50 square feet, or a 2-gallon kit over each 200 square feet.  This usage is for brushed application. Spraying may waste a large portion of the material, necessitating destructive physical analysis to verify film thickness.
     Usage of Brushing or Spraying Reducer is typically 10% to 20% of the amount of Five Year Clear Polyurethane.
     Usage of Cold Weather Accelerator is typically one unit per 400 square feet, if needed due to weather conditions.  
     Usage of Flatting Concentrate varies with the reduction of sheen, is only in the last coat, and may range from 300 to 600 square feet finished, per quart of flatting concentrate used.  
     Usage of Urethane Cleanup Solvent is at the discretion of the applicator, for cleaning up spray equipment.


     Apply first the MultiWoodPrime or Clear Penetrating Epoxy Sealer (WW Formula) according to the latest issue of Five Year Clear Polyurethane Finish, New One-to-One formula, Instructions For Use, observing all the instructions and warnings.
     Redwood or other abnormally soft woods should preferably be pressure impregnated with Clear Penetrating Epoxy Sealer (WW Formula) as their excessive physical weakness will allow premature coating failure as the coating ages, stiffens, and develops greater mechanical stress at the coating-substrate interfacial bond due to seasonal temperature and humidity variations affecting the wood.
     Two or more applications of Clear Penetrating Epoxy Sealer (Fast Formula) may be necessary to satisfy the manufacturer's instructions.

     Apply second the Five Year Clear Polyurethane according to the Instructions For Use.  Brushing or spraying reducer may be required, as well as the Urethane Cleanup Solvent.  Depending on the ambient temperature, the Cold Weather Accelerator may also be needed.
     After the last coat of Five Year Clear Polyurethane, a minimum of 48 hours at 70 F and 40% Relative Humidity (R. H.) must be allowed to elapse before the coating will tolerate water exposure without damage. Full chemical cure and the development of ultimate physical properties takes two weeks at 70 F and 40% R.H.


5100 Channel Avenue
Richmond CA 94804-4646
email: smi3th@smithandcompany.org

© copyright 1972 - 2009, The Brain Trust, a California irrevocable trust,
reprinted with permission

You can order this product from Smith & Co.