Conservar Polymeric Varnish (Gloss) 4 fl oz

Conservar Polymeric Varnish is a colorless, reversible varnish made with a methylacrylate (Paraloid B-72) resin dissolved in a common organic solvent with a UV stabilizer. It can be used both as an isolating varnish and a final varnish. The varnish can be removed with suitable solvents.

Paraloid B-72 (formerly called Acryloid B-72 in the United States) is a thermoplastic acrylic resin that provides an excellent varnish of hardness, adhesion, and film toughness together with clarity and transparency. Paraloid B-72 acrylic resin can be dissolved in toluene, xylene, selected esters, acetone, and methyl ethyl ketone. Paraloid B-72 is not soluble in most alcohols and aliphatic hydrocarbons as the sole solvent. Paraloid B-72 has been used since the 1950s in conservation as a consolidation agent and picture varnish. Extended tests have shown it to be one of the most stable resins used in the conservation of works of art. While some change in the resin occurs after it has aged, it can be virtually eliminated or reduced by adding a UV stabilizer, which is included in Conservar Polymeric Varnish.

Paraloid B-72 is insoluble in almost all purely aliphatic solvents, such as odorless mineral spirits, making it an ideal isolating varnish. It can be used with other varnishes applied as a distinct layer, for example, below Conservar Finishing Varnish or other varnishes. Conservar Finishing Varnish remains easily removable without harming the Conservar Polymeric Varnish in the layer below. Conservar Polymeric Varnish can also be used as a final varnish that is less glossy than Conservar Finishing Varnish.

Conservar Polymeric Varnish is a medium-gloss varnish that has the potential to provide good saturation on many paintings. However, it may not provide satisfactory saturation on paintings that are dark in value. Compared to natural resin varnishes, such as dammar, Conservar Polymeric Varnish has a slightly satin-like appearance. It will not saturate colors like dammar or Conservar Finishing Varnish and is considerably less glossy.

Paraloid B-72 resin in Conservar Polymeric Varnish is a polymeric resin (high molecular weight), giving it a pleasant feel or ‘brushability.’ When brushing, it has enough viscosity to give a feeling of control and easily spreads out evenly. Its primary advantage is its relatively good leveling in a single application without the tendency to sink into matte areas of a painting.

The open working time of Conservar Polymeric Varnish is short. It may be extended somewhat by adding slower-evaporating aromatic solvents. Conservar Polymeric Varnish that is brush-applied under normal conditions is generally dry to the touch within 5–10 minutes. Adding slower-drying solvents will lengthen the drying time, or adding acetone will shorten it. As with any varnish, temperature and relative humidity will also affect drying time.

Recommended Uses

Conservar Polymeric Varnish is recommended as both an isolating and a final varnish on the following paint films:

• Alkyd
• Oil
• Polymer
• Tempera

Conservar Polymeric Varnish is specifically formulated to be applied over copper or as a varnish on acrylic, oil, or alkyd paintings.

Coverage

A four-fluid ounce (118 ml) can cover approximately 50 square feet (4.6 square meters).

Directions

Before actual use, it is essential to test Conservar varnishes on test pieces to understand how they perform and how they alter the surface appearance of your paintings. For best results, apply to a test piece similar in composition to the artwork to be varnished. This will help ensure that a successful varnish application will be achieved.

When to Varnish

The best practice is to wait 6 to 12 months before varnishing with Conservar Polymeric Varnish. Oil and alkyd paint films need time (typically months) to polymerize and form a resilient film; otherwise, a coating added to an improperly cured film may cause the layers beneath to swell and loosen.

It may be possible to apply Conservar Polymeric Varnish when the thickest areas of your painting are “dry through”—not touch dry. To determine if your painting is “dry-through,” press into the thickest area of your painting with your thumb and twist it a full 90° on the paint film. If your painting is on a flexible support, such as stretched canvas, support the opposite side. The paint is considered dry-through when no loosening, detachment, wrinkling, or distortion is visible on the paint surface. This procedure is fully described in the ASTM Standard D1640: Standard Test Methods for Drying, Curing, or Film Formation of Organic Coatings at Room Temperature.

Please note, however, that the more the oil/alkyd paint is allowed to polymerize or cure, the more likely the varnish application will be successful. Always test the application of varnish on test pieces first to determine the suitability of the varnish for your application.

Preparation for Varnishing

Acclimate painting and varnish materials and tools to the same environment. At least several hours before varnishing, place all items, such as your painting, brushes, containers, and Conservar varnish, in the same room. Varnish in a dust-free environment with the least amount of air movement to avoid raising dust.

It is best to brush or spray apply Conservar varnishes. Other methods, such as applying with paint pads, sponging, or rolling, are not recommended, as they may result in foaming, loss of film clarity, non-uniform coverage, excessive film build, sagging, or deposit of materials from the application tool.

Brush Application

Apply with a wide, flat, stiff-hair brush. Conservar Polymeric Varnish can be thinned up to 20% with acetone or toluene. DO NOT MIX WITH WATER. When applying it with a brush, apply only one coat as a final varnish. Allow to dry for at least three days, and wipe the varnished surface with a soft, lint-free cloth. Some of the varnish solvent may remain in the varnish for up to one month.

Spray Application

The best way to achieve an even varnish coating is by spraying. This is particularly true for impasto surfaces. Spraying is also a useful technique for creating a matte surface. The size of the surface to be sprayed will determine the best type of spray equipment to use. Conservar varnishes can be sprayed from an airbrush, airless or air-pressure spray equipment, or refillable aerosol spray can.

To prepare for spraying, make sure all equipment is free of dirt. Work in an area free of dust and dirt, and keep work off the ground when spraying. Spray two to four light, even coats instead of one or two thicker applications, allowing enough time for drying between coats (1 to 4 hours or until the surface is tack-free).

Release the spray trigger when stopping the motion of the sprayer during application to avoid a buildup of varnish in one spot. Maintain a uniform distance from the surface and avoid spraying in an arcing motion. Make straight passes across the work, changing direction once the spray has cleared the edge of the piece being varnished. Slightly overlap the spray pattern with each pass until the entire passage has been covered.

To achieve a more uniform spray application, turn the painting 90 degrees and apply the subsequent coat perpendicular to the previous one. A typical spray application lays down a film only 1/8 to 1/4 the thickness of a brush coat application. If maximum protection of the varnish layer is required, apply multiple coats.

Drying Time

When applying multiple coats (spray application only), allow 1 to 4 hours between coats. Inspect the surface for tackiness, which may mean the coat is not sufficiently dry. Let the varnish cure for several days before packing or transporting the painting. Avoid contacting the surface with packing materials, including glassine, bubble wrap, or any other plastic, during transportation and storage. NEVER STACK PAINTINGS, whether varnished or not.

Care and Storage

As Conservar varnishes are removable, it is important that they not be painted over. Paint applied over the varnish would also be potentially removable and would pose a difficult problem in conservation or restoration attempts.

Techniques for Reducing Gloss

There are several different ways to reduce the gloss of Conservar varnish:

1. Dilute the varnish with additional solvent before using.
2. Apply a thin coating. The thinner the coating, the lower the gloss.
3. Brush the varnish as it dries. When the varnish starts to set up, continuing to brush will microscopically roughen the surface, making it less glossy.
4. Spray apply the varnish.

If the varnished surface of your painting appears too glossy, you can apply a final coating of Conservar Wax. Rub on a thin layer of wax with a soft, lint-free cloth using small circular strokes. Allow the wax to dry overnight for the highest degree of matte. Let the wax dry for 4 to 6 hours to create a satin finish, then gently buff.

Cleanup

Clean all equipment immediately following application. Clean brushes with the recommended acetone. Always make a test piece for your application and surface to ensure desired results.

Removal

Use a clean, soft, lint-free rag dampened with xylene. Xylene is a strong solvent, so care must be taken when using it. Gently rub the varnished surface and repeat the process until all varnish is removed. Allow to dry and reapply Conservar varnish. The solvents used to remove Conservar instead of those used for natural resin varnishes are less likely to damage paint films during cleaning. Conservar Polymeric Varnish is not an easy varnish to use, but you can produce an aesthetically pleasing varnish layer with practice.

Paraloid B-72 is a registered trademark of Dow Chemical Corporation. Conservar is a trademark of Natural Pigments. Rublev Colours is a registered trademark of Natural Pigments.