Paint And Body Terms And Definitions
There are numerous terms associated with auto refinishing that the average enthusiast seldom has to use in conversation until the subject turns to painting your Vette. The terminology here is just about as important as the process, especially when getting hands-on in a paint project, or even discussing the job with whomever is doing the work. Listed here are the definitions needed to speak the language of a professional automotive painter.
Accelerator ::: A chemical that can be added to some paint products or resins that speed the curing time.
Acetone ::: A powerful and fast drying solvent that is useful in clean-up equipment. It is the base ingredient in many VOC compliant products for paint reduction.
Acrylic Enamel ::: Chemically enhanced enamel formulas, which were the mainstay of the refinish industry. Acrylic enamels use a catalyst to create chemical reactions that produce a paint film with excellent durability, chemical resistance, and gloss. Acrylic enamels are still very popular products, though these paints are being phased out in some areas due to emissions regulations. A characteristic of acrylic enamels is the paint can be polished like a lacquer to a mirror finish.
Blocking ::: Sanding primer or topcoats by hand with a flat sanding block. Block sanding the primer is a key technique in getting a wave-free, show-quality result in the final finish.
Bonding Adhesive ::: Product used to bond body panels into the body structure. Corvettes are built and repaired by bonding the major body panels.
Catalyst ::: Sometimes referred to as activators, catalysts contain chemicals that interact with the resins of the base paint, allowing it to cure.
Enamel ::: A term covering a wide range of paint formulations based on enamel resins. These paint products range from spray-can to bulk paints for industrial or automotive refinish applications, and are normally air-dried, with no catalyst added. Cheap refinish enamel is notable for slow-drying, poor surface quality, and marginal durability. Although some low-line enamel products can be enhanced with available catalysts, these products are the realm of bottom-barrel cheap paint work.
Epoxy ::: A catalyzed paint or primer product notable for good durability, stability, corrosion resistance, and adhesions.
Etching Primer ::: A primer with chemicals that etches into the bare metal for better adhesion. It is sometimes referred to as self-etching primer.
Fiberglass Cloth ::: Fiberglass material used with polyester resin in repairing fiberglass bodywork. Although a strong form of fiberglass reinforcement, the weave of fiberglass cloth will often show through a finished repair, making cloth more suitable for backing-up a repair area of a panel.
Fiberglass Matt ::: Basic fiberglass reinforcement material used with polyester resin to create or repair fiberglass body panels.
Fiberglass Reinforced Filler ::: Body filler (generally polyester) with strands of fiberglass material in the mix. Good for smaller, lower-stressed repairs and some bonding applications.
Filler ::: Any material designed to fill surface flaws. Generally a term for polyester body fillers, but also sometimes used generically to cover spot putty, glaze, and even primer surfacer.
Fisheye ::: Surface defects exhibiting small circular depression devoid of paint, usually caused by surface contamination with oils or silicones. If fisheye becomes apparent when spraying, a fisheye eliminator additive can be added to the paint.
Flash ::: The time required for the majority of quick-evaporating solvents in the material being sprayed to evaporate or "flash" from the surface.
Flowout ::: The desirable characteristic of droplets of sprayed material to meld together and level on the surface once the product is applied. Air pressure, gun atomization, the amount of material being applied, and the "speed" and/or quantity of the solvents all affect the flowout.
Glaze ::: Materials used to fill minor imperfections to improve the surface quality of body filler. Glazing putty was traditionally a single component acrylic, but today, catalyzed polyester putties are commonly used. Fine grain and easy sanding are the primary characteristics of glazing putty.
Gravity Feed ::: A configuration of spray equipment where the paint material is fed into the spray gun from the top by gravity.
HVLP ::: Stands for High-Volume/Low-Pressure. It refers to the design of modern spray equipment originally introduced to meet air-quality regulations by reducing air-borne overspray.
Lacquer ::: The old standard for custom paintwork. Lacquers are a distinct paint type characterized by fast drying times and the ability to be easily polished to a beautiful luster. Poor chemical resistance and durability are the downside, often resulting in surface cracking and fading. Older Corvettes were originally painted with acrylic lacquer paint.
Mixing Ratios ::: The amount of various components in the proper proportions to produce the final mix for spraying.
Orange Peel ::: A surface flaw condition in which the paint goes on with too much texture. Usually caused by improper air pressure, mixing ratio, solvent speed, gun technique, or a combination of the preceding.
Overspray ::: Atomized particles of the refinish materials being sprayed that become airborne and do not flow onto the panel being sprayed. Overspray becomes debris, which can ruin the finish or detailing of areas that are not being painted, and can settle as unwanted dust on adjacent panels to be painted in a poorly evacuated paint booth.
Pinholes ::: Surface flaws in the form of small pin-sized holes in the paint, often resulting from excessive solvents, inadequate flash time, or surface contamination.
Polyester Resin ::: Resin type used for fiberglass work, and the material basis for the Corvette fiberglass body.
Primer-Sealer ::: A primer used to isolate the existing substrate, or to provide some filling and surface enhancement before the finish color coats. Sealers are generally not sanded.
Primer-Surfacer ::: A primer designed specifically to build thickness for filling shallow surface flaws by sanding.
Reducer ::: Generic term for the solvent used to thin (reduce) enamels, urethanes, and epoxies.
Seam Sealer ::: Putty-like product used to seal seams or gaps in the body. Available in solvent-based formulations, as well as water based, in bulk cans, or caulking tubes. Seam sealer is used in hidden areas of the bodywork, such as the door jambs and cowl where appearance is a secondary concern.
Shrinkage ::: The characteristic of paint or filler to "shrink" with time as a full cure is reached, making surface flaws and sanding scratches reappear. Common with older air-dry, lacquer-based primers and acrylic spot putties.
Single-Stage ::: A paint system in which the color and gloss properties are both contained in a single topcoat product.
Substrate ::: The surface any primer or topcoat is applied over.
Suction Feed ::: A configuration of spray equipment where the paint material is drawing into the gun from a cup at the bottom by the venturi action of the gun.
Tack Cloth ::: Cheesecloth impregnated with a tacky coating used to wipe dust or dry overspray from the surface before spraying.
Thinner ::: Solvent used to thin lacquer-based products.
Two-Stage ::: A paint system in which the color is applied as a primary product (basecoat); followed by the clearcoat to provide the gloss and reflectivity.
Urethane ::: Similar to acrylic enamels, but using urethane resins. Urethane has all the desirable characteristics of acrylic enamel, but generally with enhanced durability.
VOC ::: Volatile Organic Chemicals. The VOC levels of the final sprayable mix of the various undercoat, paint, and clearcoat products is highly regulated in some regions.
Wet-Sanding ::: Sanding with waterproof sandpaper using water to wash away the sanding debris. Creates a higher quality surface than dry sanding, and allows the sandpaper to last longer without clogging.