This is probably the most overlooked part of painting wood, and in many ways is the most critical. Your work is only as good as the canvas upon which your creation takes life. Paint will not fill in cracks, dents, holes or other imperfections in the wood and keep them hidden after it dries. In fact, those imperfections will probably be even more apparent. If the wood you want to paint has paint already on it, you may have to remove it before adding a new coat. Take a putty knife and scrape away as much paint as you can without getting too persnickety about coverage; don’t worry, you’ll sand away smaller flecks of residual paint before the preparation is done.  Unless the existing surface is an oil based stain or finish, do not use chemical strippers. Scrape as much off as possible and then use a trisodium phosphate (TSP) solution to clean off the rest of the loose paint and grime. Rinse well. If your wood is treated with a stain or a finish, apply TSP to the wood. Instead of trying to remove the stain or finish entirely, focus on cleaning and sanding it (more on sanding later) in order to give the paint a porous surface to adhere to. Stripping the paint isn’t always needed. In fact, you can often paint over existing coats. This may call for a primer, though, if your paint isn’t sticking well to the earlier coat. Use a flexible putty knife and fill in all the areas needing attention. It is better to use too much in this step than not enough. You will sand down the area after it dries and hardens, so it doesn't need to be perfect at this step.  Use regular spackle or joint compound to fill in small or shallow scratches. Try to use spackle with a primer included. Wait to dry completely before sanding. Caulk areas of long and deep cracks. Use a tiny bead of caulk, smoothing it out well. Wait to dry completely before sanding. Start by sanding down the area where you've used putty or filler before moving to the rest of the surface for an even feel. Use a fine grade sandpaper for this work sanding the wood with 80 to 100 grit sandpaper, making sure to remove any paint that’s still on the surface. Finish off with fine 150-grit or higher to smooth out the surface and get it ready for priming. Remember to work the sandpaper with the grain of the wood, not against it, and to keep power sanders moving. If you have a vacuum, vacuum off the wood thoroughly, followed by a sweep with a tack cloth. If you don’t have a vacuum, wipe off the dust or residue with a tack cloth, finishing off with a damp cloth. Wait for the wood to fully dry. Paint or primer won’t adhere properly to dirty surfaces. Paint does its job best when the surface that you apply it to is clean. If you want a section of the wood to remain unpainted, or you want to paint a section of the wood a different color, you'll want to use tape to cover the parts of the wood you don't want to paint. You can get specially-treated tape designed for latex paint, like Frog Tape, at most hardware or home repair stores. These kinds of tapes adhere to wood well and are designed to minimize paint seeping into the pores of the wood. If you want to leave parts of the wood unpainted, you'll want to tape off at this stage of the prep. If you want to paint the wood different colors, you'll want to tape off after you've primed all the wood and painted specific sections. Primer helps paint achieve a uniform, rich look on top of wood. Apply one coat for an even look in your final product. If priming raises the grain of the wood, consider sanding with a fine-grit sandpaper before the final coat of primer. (Be sure to wipe off excess residue before applying your coat of primer.) Follow instructions on your primer when calculating time between coats as well as the number of coats.  Which color primer should you use? Use grey primer for darker coats of paint and white primer for brighter coats of paint.     Should you use oil-based vs. latex-based primer? For many years, professionals instructed painters to use an oil-based primer on wood and follow it up with latex-based paint. That is not always the case now. Oil-based primer adheres to wood better, but it's also less flexible than latex primer, which means it's more susceptible to cracking. On the other hand, oil-based primer is usually the more durable of the two. Unless you are painting wood outdoors, oil-based primer is probably your best bet. Should you use a spray primer or brush-on primer? It's mostly a matter of preference. Spraying is easier and faster, but it usually requires several coats to get good coverage. Brushing is slower and more painstaking, but creates a thinner, more even layer of primer onto which to paint.
خذ وقتك في تحضير الخشب لطلائه. أزِل أي طلاء قديم عن الخشب كخطوة ضرورية. املأ كل الحفر العميقة مكان الدبابيس والإزميل بمعجون الخشب عالي الجودة، إذا كان ذلك ممكنًا. قم بصنفرة الخشب بورق صنفرة خشن ثم أنهِ العملية بورق صنفرة ناعم. أزِل أي غبار أو بقايا خشبية بمنشفة نظيفة. ضع شريطًا لاصقًا على أي أجزاء من الخشب لا ترغب في طلائها. ضع الطلاء التمهيدي على الخشب.