Fix imperfections prior to painting for a smooth, clean finish
Before you tackle a painting project, odds are you'll have to patch up the
surface you're about to paint. In some cases, repairs may be more than just a
way to prep a surface for paint or stain -- they may be necessary to preserve
structural integrity. There is a wide range of patching and repair products
available for use on wood, drywall, metal and more. In most cases, patching up
a hole or cracked surface is an easy task for any do-it-yourselfer. As you
plan out your project, use the following questions to help guide you to a
better understanding of the available materials and how to best utilize them:
Compounds, Plaster, General Use Products and Application
Prior to selecting which type of patch or repair product you want to use, you need to know a little bit about which types can be used on different surfaces. You'll also want to know how long they take to dry, what size holes and cracks they can be used to fill and how they are applied. Generally speaking, patch and repair products can be divided into three groups -- compounds, plaster products and general patch and repair substances. Understanding which type will work best on the job at hand will greatly improve the chances of achieving a high-quality repair, as will properly preparing the surface before applying any type of repair product.
Compounds: Compounds usually have the consistency of thick mud and are easy to apply. The period during which a compound remains workable is the time in which it can be shaped and manipulated before it hardens. Dry time refers to how long the substance takes to completely set. Spackling compounds are ideal for repairing hairline cracks and must be applied quickly and efficiently since they are typically only workable for a few minutes. Allow them between one and five hours to dry before applying paint. Glazing compounds provide a tough, durable seal between single pane glass and wood or metal window sashes. Stronger compounds tend to resist damage better but may be more difficult to sand after they dry.
Plaster: Plaster products are often available in powder form and are
mixed with water to create a paste-like substance that can be applied to
cracks and holes. Patching plaster is a substance that is used for interior
plaster repairs and generally dries in a short period of time. Wet the surface
of plaster walls prior to applying patching plaster to help it adhere better.
Plaster of Paris is an easy-to-mix substance that works well for filling holes
in interior plaster walls and ceilings. It can set very quickly, so avoid
mixing too much material, as it will harden before you get a chance to use it.
Plaster of Paris may be sanded after application to make painting easier.
General Patching and Repair: Unlike compounds and plaster, general
patch and repair substances are available in a number of different forms,
including putty, epoxy, tape and patching. Putty is a versatile substance that
provides strong adhesion and can be used to fill holes, cracks, joints and
other defects in wood. Epoxy provides a strong bond and can be sanded and
carved after it hardens. It is slightly more expensive than other repair
substances and can be tricky to apply, but it offers tremendous durability,
particularly when used to repair rotting wood. Wood must be completely dry
prior to applying epoxy because moisture can interfere with the bonding
|GENERAL PATCHING AND REPAIR|
Surface Preparation and Application: Prior to doing any sort of patching or repair work, you'll need to make sure that the surface of the area you're working on is clean and dry. Dust, dirt, grease, oil, stains and even paint may need to be removed, so be sure to consult the manufacturer's instructions before application. Air temperature is also important, as extreme temperatures can affect consistency and lengthen or shorten drying time. Drying times vary widely between substances, so make sure your repair is thoroughly dry prior to painting or staining. In most cases, patches and repairs can be accomplished with a fairly simple selection of tools. A putty knife is the most essential tool, as it can be used to fill holes and spread patching substances over cracks. Buckets and mixing tools may be needed for some plasters while sandpaper, wood rasps and files will help you achieve a smooth surface once you're finished.
Tape: When repairing drywall, you'll need to use tape prior to applying joint compound. Paper tape requires a coat of joint compound to be applied first while self-adhesive fiberglass tape can be applied directly to the surface. To save time, use a banjo, which can apply tape and mud simultaneously.
Primer/Sealer: Some surfaces may need to be primed and sealed before being repaired. A good example of this is when working to glaze sash corners. Be sure to thoroughly read the manufacturer's instructions to ensure proper application and repair.
Sandpaper: If you're using a patch product that leaves a rough surface behind, sandpaper will be instrumental in smoothing out the surface to help it blend in with the surrounding area. Sanding is also necessary before painting in most cases, and scuff sanding in between coats of finish will often help subsequent coats adhere more readily.
A putty knife and sandpaper will come in handy for applying and smoothing patching substances.