Professional Application Guide - Alexseal

Project ConsiderationsDark Color ConsiderationDue to the heat absorbing nature of dark pigments, yachts painted with dark colorscan experience surface temperatures of over 93° C (200° F). While light colors reflectheat and only reach ambient air temperatures, dark colors absorb heat. To address thegrowing trend toward dark yacht finishes, several issues must be considered.The increased temperatures of dark colors can cause a variety of effects on the yacht.One such effect is the air conditioners run longer and harder to keep the yacht cool.Higher surface temperatures will make increasingly difficult to touch exterior surfacesby hand (e.g. when washing the vessel) and surface inconsistencies are magnified.High surface temperatures can often cause surface imperfections called print-throughor post-cure. This occurs due to heat amplifying the natural expansion and contractionof the vessel – resulting in a visibly “printed” image in the finish of the underlyingsubstrate – such as glass fiber, core patterns, welded seams, plank seams orunderlying fasteners. Even when materials and fabrication practices are designed todeal with increased temperatures, a dark yacht’s surface will inevitably move more thananother painted with a light color.Increased costs should be expected regarding additional materials, labor andproduction time for fairing and painting needed to decrease the effects of hightemperatures on exterior surfaces. Extra surfacing and fairing steps are required tomeet minimum quality levels in darker colors.Project Considerations5. Apply ALEXSEAL ® 442 Finish Primer, Dark Gray and finish sand with 320 - 400 grit.Spot prime any sand-through areas so the primed surface is one consistent color.6. Apply three coats of ALEXSEAL ® 501 Premium Topcoat as a “Show Coat”. Afterconfirming acceptability of the fairing and surfacing quality, sand the surface with320 - 400 grit and thoroughly clean to prepare for a final topcoat application. Spotcoat any sand-through areas to achieve one consistent color.7. Apply 2 - 3 coats of the final ALEXSEAL ® 501 Premium Topcoat dark color.Note:Dark finishes may show scratches and damages more easily. Extra careshould be taken when choosing wash-down equipment and in the placement offenders and lines. Additional wash-down care and maintenance procedures are needed,especially when removing dried and sun-baked salt residue. Please contact yourALEXSEAL ® sales and support representative for additional information.Additional NotesDuring application, special attention must be given to film thickness and coverage, assurface imperfections are magnified in darker colors.The following steps should be considered to reduce the imperfections commonlyamplified when using dark exterior finishes.Note:The resulting costs could double or triple over a typical light color finish forthis type of application. Even when these steps are followed visible surfaceimperfections may still occur.Tips to Decrease Imperfections in Dark Colors:1. Use heat resistant resins and core materials during the lay-up and building process.2. Elevate the surface temperature of the vessel by using any of the followingpractices: (A) use of heat lamps, (B) applying a temporary dark color and exposingit to the sun, (C) building an enclosed structure to cure the boat with heaters. Theresin and core manufacturer must be consulted for advice on what temperaturesand curing schedules are recommended for these processes.3. Fair the surface with ALEXSEAL ® 202 Epoxy Fairing Compound. The fairing shouldbe finish sanded with fine sandpaper to minimize sand scratch print-through in thetopcoat.4. Apply ALEXSEAL ® Fine Filler 303 and/or Super Build 302 and then block sand toremove imperfections.18ALEXSEAL ® Professional Application Guide version 0.4.3ALEXSEAL.COM > Europe: +49 0 40 75 10 30 > North America: +1 843 654 775519