known as "palming" (Fig. 93). Gloves should be worn when handling epoxy 

 materials as many people have a toxic reaction to epoxies. 



WELD OR 



CORRODED AREA"^. > 





^-APPLIED BY 

 s /^ PALMED EPOXY 



\ 





J WATER 







Figure 93. "Palmed" application of epoxy 

 underwater coating. 



Certain epoxy polyamide coatings and mastics will cure on moist surfaces, 

 or even under water. It is this property that allows these materials to be 

 utilized for coating and for repairing wet or submerged structures which 

 require protection. Epoxy coatings have excellent corrosion resistance to 

 most chemicals. They perform well in alkaline media but are only fair in 

 contact with acids. Because of their inertness they are sometimes difficult 

 to repair or topcoat. Because of adhesion problems, very few coating 

 materials will adhere to a well-cured epoxy. Epoxy coatings tend to chalk 

 and for this reason, colors fade, particularly dark colors. The lighter ' 

 colors are most frequently specified for use where the coating will be 

 exposed to sunlight and weather. To summarize, epoxy coatings have excellent 

 corrosion resistance and toughness, but are fair to poor in - weather re- 

 sistance . 



(9) Epoxy Phenolic . Epoxy phenolic coatings are epoxy-type 

 coatings which have been modified by the addition of phenolic resins. The 

 phenolic resin adds corrosion resistance as it promotes cross linking and 

 bonding of the epoxy resin as illustrated in Figure 94. 



With the increased resistance of the epoxy phenolic coatings to attack 

 by corrosive chemicals or environments, these materials find application as 

 linings for tanks, barges, ships, and piping. 



329 



