Woodworker's Journal 2008-32-3, страница 90
Skill Builder Sealers: Clearing up the Confusion How to Seal the Deal Start I suspect far more people are confused about sealer than understand it. As a result, questions abound, such as: "Is it the same thing as pore filler?" (No.) "Should I use sealer before my topcoat?" (Sometimes.) "Is there a universal sealer that will work with every finish?" (Yes.) Let's clear the air and explain what sealer is and when to use it. What is Sealer? The first coat of finish applied to raw wood acts as a sealer. Although any coating can act as a sealer, there are specially formulated sealers that accomplish particular jobs. Some coatings don't need sealers, but sealers can be very helpful in certain situations, and they can perform all or some of the following functions: Lock in surface contamination such as grease, oil, wax, sap or naturally occurring antioxidants. Prevent spongy wood from excessively absorbing repeated coats of finish. Reduce grain raising under waterbased finishes. Act as a tie or barrier coat to allow any finish to go over any stain. Prevent dye bleeding. Increase adhesion of the topcoat to the substrate or stain. Prepare a finish, old or new, for re-coating with a different topcoat. Make it easier to sand the first coat of finish. Provide a superior moisture barrier. Universal Sealer While a variety of specialty sealers exist, formulated for particular coatings and tasks, choosing among them can be daunting. Fortunately, there's a universal sealer that will do everything on the list above, and that's dewaxed shellac. It will go over every wood, every stain and between all coatings. The easiest way to buy it is as Zinsser SealCoat™, which is pre-mixed dewaxed shellac, modified to have a longer shelf life than regular shellac. —Michael Dresdner^P When using a shellac sealer, the author prefers to flood it on liberally by hand, then wipe off the excess with shop towels. Wear gloves for this procedure. Finish ^MORG ON THG W6B Skill Builder For a downloadable article on sealers and pore fillers, go to woodworkersjournal.com and click on the icon at left. Or send a SASE to Woodworker's Journal, Skill Builder 3, 4365 Willow Drive, Medina, MN 55340. 90 June 2008 Woodworker's Journal |
