CoatingsPro Magazine

SEP 2015

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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COATINGSPRO SEPTEMBER 2015 25 w ith high-densit y polyethylene second layer containment and cathod ic protection (CP) of the bottom plate, shou ld the underside of the tank plate be coated? We have a c lient who says coating the under- side of bottom plates causes some problems w ith CP and recommends no coating. Apparent ly when weld ing the base plates together, the coating is overheated loca l ly and w i l l then d isband. T he CP w i l l not protect the d isbanded areas, which are in ef fect a shield. Wou ld you recommend leav ing an uncoated str ip at the plate edges to avoid the d isbanded zone, and, if so, how w ide? A: We genera l ly specif y 300 ยต m (11.8 mi ls) of coa l tar epox y on the f loor plates before lay ing and weld ing. For the coated area, use a rea listic coating brea kdow n f ig ure and desig n the CP accord ingly. If you have secondar y containment, insta l l a per forated nonmeta l lic tube under the tank c lose to the tank f loor w ith a pu l l w ire so you can check polar iza- tion of the cathode sur face. A: If you have a choice here, CP always works best (less amperage and further throwing power) with a coating in place. A: If t here is second a r y cont a i n- ment, a s t here is i n most c a ses t hese d ays, a nodes a rou nd t he t a n k do not apply (one need s a l so to consider t he t a n k d i a meter a nd potent i a l sh i f t at t he center i f per iphera l a nodes a re u sed). One mu st u se a c lose a node of t he g r id or d ist r ibuted t y pe; u nder t hese cond it ions, coat i ng is t he best way to go. We h ave successf u l ly done t h is on more t h a n 20 0 t a n k s. T he space bet ween t he t a n k a nd t he second a r y cont a i nment is never >50 0 m m (19.7 i n.), so a node spac i ng vs. c u r rent d ist r ibut ion need s to be c a ref u l ly considered i f t he pl ates a re to rem a i n ba re. CP Mortartec Ceramico TM is an advanced underlayment for epoxy coatings, high performance repair, restoring and resurfacing or as your stand-alone protective cementitious liner 877.GO.EPOXY | epoxytec.com INTRODUCING THE Next Generation of Cement Eliminate failures due to inadequate mortars Finally stop outgassing... for real! Increase adhesion to both your underlayment and your epoxy top coat Mortartec Ceramico TM is a cutting edge, epoxy modified mortar. Epoxy combined with ceramics and fibers to produce one of the most coveted mortars in the industrial market today. The result is a smooth mortar application with the hardest, sealed surface in the industry. FIND OUT WHAT ALL THE HYPE IS ABOUT Call Us Today! Wr i te in Re ad e r In q u ir y #361

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