Mural and Architectural
GOLDEN Mineral Spirit Acrylic Varnishes with UVLS (Ultra Violet Light Stabilizers) dry to a tough, yet flexible protective finish. The UVLS system provides increased resistance to the harmful effects of ultraviolet radiation, making the product suitable for exterior as well as interior application. For restoration purposes, the varnish may be removed with full strength commercial mineral spirits ( i.e.: paint thinner or white spirits ), or distilled or rectified turpentine.
MSA Varnish can be used over a wide variety of paints, including acrylic, oil, alkyd, egg tempera, watercolor, and casein. As a topcoat for acrylics, it provides a harder, lower tack surface that is much less susceptible to dirt and is more mar resistant. It can also be mixed with oil and alkyd paints to accelerate drying and improve flexibility. For recommended ratios of MSA Varnish and oil/alkyd paints, please refer to our MSA Gel (Mineral Spirits) Product Information Sheet.
MSA Varnish (Gloss) dries to a highly reflective finish. MSA Varnish (Satin) offers moderate reflection, similar to most matte varnishes. MSA Varnish (Matte) finish is exceptionally flat. The different finishes can be intermixed, or used sequentially, to achieve the desired sheen. Note that the matte and satin MSA varnishes will lighten dark value colors, which is typical of reduced sheen varnishes.
As a solution polymer, MSA Varnish is clear when wet . Compared to aqueous varnishes, this allows for better visual properties during application. It also suffers significantly less from foam generation and pinholes that can detract from the clarity and appearance of the finish. The varnish produces an extremely level finish, and is able to coat slick supports including glass and most plastics and metals .
MSA Varnishes must be thinned before use . They have been made thicker than the traditional application viscosity to maintain an even suspension of the solids within the varnish. Often, particularly in matte finishes, settling can result in streaking within the varnish film. Please see the following for more information:
TEST FOR YOUR APPLICATION
Prior to actual use, it is very important to experiment with Golden varnishes on test pieces to become aware of how they perform and how they alter the surface appearance of paintings. For best results, apply to a test piece that is similar in composition as the artwork to be varnished. This will help ensure that all variables are accounted for, and a successful varnish application will be achieved.
Only intended for acrylic paintings, do not use on oil paintings.
For future conservation and varnish removal purposes we recommend the use of an isolation coat prior to varnishing. An isolation coat is a permanent, non-removable coating that serves to physically separate the paint surface from the removable varnish. This will help protect the surface if the varnish is ever removed and make future cleaning and conservation easier to avoid working directly on top of the pigmented part of the work. Therefore, even if painted with delicate washes or large areas of colors that could potentially bleed, a clear barrier would safely cover the painted surface. It will also seal absorbent areas, which will result in a more even application of the varnish. In the event that no varnish gets applied, the isolation coat serves to decrease the water sensitivity of the paint surface, affording protection during routine cleaning/dusting.
Given the current state of conservation science, we feel the use of an isolation coat provides the most protection. However, isolation coats are also significant and permanent additions to a painting and inevitably will cause changes in the painting's surface qualities. Whether these changes are acceptable is an aesthetic decision that each artist needs to make after sufficient testing. In addition, since it is non-removable, any mistakes or problems during this procedure cannot be easily corrected and there is always an element of risk that needs to be considered. We strongly encourage the artist to practice these procedures thoroughly so they feel confident and become familiar with any unforeseen problems. If you have any questions or concerns regarding the proper use or application of an isolation coat, please call Golden’s Technical Support Department at (800) 959-6543.
For brush application, the appropriate isolating medium can be made by diluting Golden Soft Gel Gloss with water (2 parts by volume Soft Gel Gloss to 1 part water). If a spray application is desired, a 2:1 mixture of Golden GAC-500 to Transparent Airbrush Extender can be applied with an airbrush, touch-up spray unit or commercial spray equipment. The absorbency of the surface will dictate the number of isolation layers required. For relatively non-absorbent surfaces, as is the case with a uniform paint layer, one coat brush applied or two coats spray applied are recommended. For more absorbent surfaces, which tend to be very matte, it is recommended to apply sufficient isolation coats to achieve a satin sheen on the surface. This may require two or more brush applied coats or three or more spray applications.
The isolating layer is of critical importance when applying a matte varnish over an absorbent surface to prevent a cloudy or "frosted" appearance from occurring. This frosted appearance results from the varnish and solvent being absorbed into the support, while the matting agent remains exposed on the surface. While we have carefully selected the matting agent that is in Golden varnishes to be as transparent as possible, it is still a dry particulate material. When the matting agent is deposited onto the surface, and is not a part of a continuous varnish layer, it appears as a white solid. If varnishing water-soluble paints, including watercolor, gouache and tempera, the isolation coat must be sprayed on in very light layers to avoid solubilizing the paints, which could cause loss of distinctness of the underlying image.
MSA Varnishes must be thinned before use . They have been made thicker than the traditional application viscosity to maintain an even suspension of the solids within the varnish. Often, particularly in matte finishes, settling can result in streaking within the varnish film.
Thinning: Material can be thinned with full strength commercial mineral spirits (i.e.: paint thinner or white spirits ) as needed (do not use “odorless”or “low odor” solvents, unless specified or tested first for compatibility). A 20% to 30% dilution provides ease of brushing (a 3:1 mixture of varnish to thinner is a good starting point). For spray application further thinning may be required (adding up to equal parts varnish and thinner).
While turpentine that is specifically labeled as distilled or rectified is also a potential choice it is a more aggressive, ‘hotter’ solvent and so presents additional health concerns and a greater chance of reactivating previously applied layers of varnish. Because of these reasons we tend to not make this one of our top recommendations for thinning.
Stir thoroughly before using . Apply varnish as evenly and as smoothly as possible. Avoid heavy build-ups. Maintaining a wet edge when overlapping will yield the most even finish. If applying multiple coats, avoid overworking the wet varnish to minimize resolubilizing of the previous coats. Allow previous coats to dry thoroughly before recoating.
Drying/Curing Time: Usually becomes tack-free and suitable for recoating after 3-6 hours. Most curing will occur within two weeks. May be mixed with oils or alkyds to modify viscosity, drying time or improve resistance to cracking.
Coverage: 400-500 sq. ft. per gallon if by brush application; 800-1000 sq. ft. per gallon for spray application.
This product is intended for a final picture varnish only! Do not repaint surface. MSA Varnishes should not be mixed with acrylic emulsion polymer paints or mediums. Clean tools with mineral spirits or other appropriate solvent immediately after use.
It is preferable to brush or spray apply Golden varnishes. Other methods, such as sponging or rolling, are not recommended, as they may result in problems such as: foaming, loss of film clarity, non-uniform coverage, excessive film build, sagging, or deposition of materials from the application tool.
Use a stiff, white hair, Chinese bristle brush with split ends. The split ends and memory of this type of brush will result in a smooth, even coat of varnish. The size of the piece to be varnished will determine the size of the varnish brush. Work from a shallow container to help control brush loading. The varnish solution should wet only the lower 25-30% of the length of the bristles. It is always best to apply the varnish on a horizontal surface in order to minimize running or sagging. If vertical application cannot be avoided, as with a mural, it is extremely important that the varnish be thinly applied. In either case, it is better to apply two or three thin coats with sufficient drying time in between, rather than one thick coat of varnish. The latter will take longer to cure, staying soft for some time, and could result in drips or a cloudy film. Apply the varnish in a manner that allows it to be brushed out to the most uniform, thinnest film possible. Mentally divide the work into regions to be covered by each loading of the brush. These may be based on a systematic grid-like sequence or may follow natural boundaries of the piece. Maintain an even application by working from the center of each region outward. Lightly overlap into still wet, adjacent sections. When applying a satin or matte varnish, never apply more than two coats. If multiple coats are desired, start with the gloss varnish to build up and establish the multiple layers, then finish with one or two coats of the satin or matte finish. A thick film of these reduced sheen varnishes will result in film cloudiness, and loss of clarity.
The best way to achieve an even coating of varnish is to spray apply. This is particularly true for impasto surfaces. Spray application is required for any surface where the paint film is fragile, such as gouache, and should not be touched by application tools. 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. These varnishes can be sprayed from an airbrush, airless or air pressured spray equipment, or refillable aerosol equipment. In preparation 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 three to four light even coats instead of one or two thicker applications, allowing enough time for drying between coats (1-4 hours, until surface is tack free). Release the spray trigger if the motion of the airbrush is stopped during application in order to avoid an uneven build of varnish in one spot. Maintain uniform distance from the surface, and avoid the tendency to use 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 piece has been covered. To aid in achieving a more even application, turn the painting 90 degrees in order to apply the subsequent coat perpendicular to the previous one. A typical spray application lays down a film only 1/6 to 1/4 the thickness of a brush coat application. If maximum protection is required of the varnish layer, apply multiple coats. This is especially important when protecting colorants that are not inherently lightfast, as the thicker the total varnish film, the greater the protection from ultraviolet radiation. Because it is not recommended to apply several coats of a satin or matte finish, underlying layers should be established using a gloss varnish.
Murals and Architectural Applications
Any paint or topcoat applied to a building, including interior or exterior walls, is considered an architectural coating and subject to regulations limiting the amount of VOC’s (Volatile Organic Compounds) a product may have. Murals painted directly onto these surfaces, therefore, will fall under the same guidelines and all paints, mediums, and varnishes being used will need to comply with the same rules. Containers that are 1 Liter (1.05 Quarts) or less in size, however, are currently exempt from these requirements.
Murals painted directly onto architectural surfaces
- Gallon sizes of our MSA Varnish and Acrylic Glazing Liquid are prohibited in the United States for architectural applications, including interior and exterior murals painted directly onto walls and ceilings.
- Quart containers of our MSA Varnish and Acrylic Glazing Liquid are allowed and can be used. The rate of coverage for these products is approximately 75-150 sq. ft. per quart, depending on the type of substrate and method of application.
- Solvents needed to thin MSA Varnish might be limited or prohibited by similar VOC requirements.
- Always check local and state VOC regulations as these may include additional restrictions.
Murals painted onto canvas, panel, and other supports
- Currently there are no restrictions for murals completely painted and varnished on an independent support which is then mounted onto an architectural surface.
Call or email Technical Support for additional information or assistance.
Clean all equipment immediately following application. GOLDEN MSA Varnish should be cleaned from tools with the same solvent used for thinning, followed by soapy water wash and clear water rinse.
Drying Time/Care and Storage
The isolation coat should cure for 1 day before varnishing. When building up multiple coats, allow for 3 - 6 hours in between coats. Gently inspect the surface for tack, which may signify that the coat is not sufficiently dry. Let varnish cure several days before packing or transporting art. During transportation and storage, avoid contact of the surface with packing materials, including glassine, bubble wrap or any other plastic. NEVER STACK PAINTINGS, whether varnished or not. Please refer to the following Just Paint article for more information about the handling, storage and transportation of acrylic paintings:
Painting Over MSA Varnishes
As Golden 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.
The isolation coat should cure for 1 day before varnishing. When building up multiple coats, allow for 3 - 6 hours in between coats. Gently inspect the surface for tack, which may signify that the coat is not sufficiently dry. Let varnish cure several days before packing or transporting art. During transportation and storage, avoid contact of the surface with packing materials, including glassine, bubble wrap or any other plastic. NEVER STACK PAINTINGS, whether varnished or not.
Care and Storage
As Golden 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.
If milkiness or opacity occurs in varnish layer, then
- if using a satin or matte varnish, and this only occurs over dark colors, this may simply be the nature of such a reduced sheen varnish (caused by the presence of the matting agent). There is no way of applying a satin/matte finish to a dark color without lightening it (the more matte the finish, the more potential for lightening dark areas). To restore the depth of the dark colors, apply a higher gloss to restore some of the sheen.
- if this is uniform across much of area, regardless of the darkness of the underlying colors, it may be caused by moisture entrapment. High humidity or a damp surface under the varnish layer, often causes loss of clarity. Using a warm, forced air source to blow across the surface should help the moisture evaporate, restoring clarity.
- if varnish is not properly thinned, or is shaken or stirred excessively, air bubbles may become trapped within the dry film, causing a loss of clarity. The varnish must be removed.
- if a "frosted" area appears, a satin or matte varnish may have been applied over an absorbent surface (this is common for spray applications). The varnish must be removed, the surface sealed to reduce absorbency (apply gloss varnish), followed by application of a reduced sheen varnish.
If reflectance is not uniform, then
- if surface has varying absorbency, this may result in uneven gloss. Ideally, such a surface would first have isolation coat applied to provide a more uniform surface. However if varnish has already been applied, the surface must be sealed by applying 1 or more additional coats of gloss varnish, followed by the desired sheen varnish.
- improper mix of varnish. The varnish/solvent mixture was not thoroughly mixed. If different sheens were blended together (gloss with matte), they may not have been thoroughly mixed. If the diluted varnish is used over a long period of time without restirring, it may be separating (matting agents settling). To achieve a uniform finish, start with a fresh mixture of varnish/solvent (thoroughly stirred) and apply another coat (may also consider removing the existing varnish layers).
If brush strokes remain, then
- the varnish may not have been thinned sufficiently to level during application.
- the solvent was not compatible with the varnish.
- if the surface was absorbent, it may have caused the varnish to dry too quickly, and not allow it to level.
If the MSA Varnish will not thin down, then
- solvent is not strong enough to be compatible. Use a stronger solvent (distilled or rectified turpentine, a recommended and tested full strength commercial mineral spirits, etc.) See the following tech sheet for recommended solvents:
When spraying, if the surface is very pebbly or textured, then
- the varnish may have dried before reaching the surface. This could be caused by insufficient thinning (add more solvent), an extremely dry environment (add humidity, reduce heat, limit air flow) or by excessive air flow (reduce air pressure).
If the varnish is sinking in and not developing sufficient gloss, then
- the surface is too absorbent. Apply additional coats of isolating layers (only if no varnish is yet applied) or gloss varnish. Excessive dilution of varnish may also result in this problem.
If the varnished surface is too glossy, then
- apply a satin or matte finish of the same kind of varnish already applied.
If the varnished surface is too matte, then
- apply a gloss or satin finish of the same kind of varnish already applied.
Technical Support is available to answer questions at (800) 959-6543 or by emailing email@example.com.
Removing a varnish is a very consequential process that should not be taken lightly, as the appearance of the artwork can be changed or damage could result from improper handling. The task is often best left to a professional conservator, particularly with works of special significance or unknown composition. However, there are times, as when something has gone amiss in the application, that it may be appropriate for the artist to do the work.
Golden MSA Varnish films remain soluble in such solvents as full strength, commercial mineral spirits, distilled or rectified turpentine, acetone, benzene, toluene, naphtha and some alcohols and esters. However, many of these solvents can damage the acrylic paint, and are not recommended for removing varnish from paintings. The solvent of choice should be full strength commercial mineral spirits (i.e.: paint thinner or white spirits) or distilled or rectified turpentine. Odorless or low odor solvents are often not strong enough.
Before embarking on a varnish removal mission, carefully consider the materials that are to be used, and how they can be used in a safe, controlled manner. Varnish removal requires the use of solvents, thus requiring proper personal protective equipment. Such equipment includes, but is not restricted to, appropriate respirator, impervious gloves and aprons and chemical splash goggles or face shield. Careful inspection of the labels on the solvents to be used should aid in determining your safety needs. Also, work in an area with adequate ventilation and guard against ignition sources and high temperatures, which could cause vapors to ignite.
First, test the solvent on a small area of the painting , or preferably on a test piece, to determine its effectiveness at dissolving the varnish. Another quick check may be made by mixing the solvent into the wet varnish. If the varnish becomes thinner, the solvent is compatible. If the varnish gets cloudy and/or thicker, the solvent is not compatible and should be avoided. Unfortunately, there is no way of knowing without trying.
A good procedure for removing the varnish is to start with a soft, low lint cloth (50/50 cotton/polyester T-shirt material works well). Saturate this cloth in solvent and lay over an area of the varnished surface. If possible, work with the painting in a horizontal position, on a table or floor. If the work must be done vertically, as on a wall, a method would have to be devised for keeping the saturated cloth in contact with the varnished surface. In either case, to minimize solvent evaporation, use a plastic sheet to blanket the saturated cloth.
Work in areas no larger than 2 square feet per application . Larger areas tend to become cumbersome and make thorough varnish removal difficult. Allow the saturated cloth to lie on the painting for 2-5 minutes. Then, remove the cloth and use a clean solvent-dampened cloth to gently pat the surface to remove the varnish. Excessive force may damage the paint layers below the varnish. Repeat this process until the entire painting surface has been treated.
After a single treatment over the complete surface of the painting, some residual varnish may remain. This may be indicated by an extremely tacky or gummy surface. Repeat the procedure, and continue doing so until the varnish has been sufficiently removed. Proceeding with more solvent exposure may result in some swelling of the paint layer.
The solvent soaked cloth and leftover solvent should be handled and disposed of carefully. Never pour solvent down the drain. Small quantities can be allowed to evaporate. Larger quantities can be saved for reuse or treated as hazardous waste. The cloth should be allowed to dry completely in a well-ventilated area before disposal or putting into storage for another use.
Adhesion: Adheres to most non-oily surfaces, including most plastics and degreased metals. May exhibit poor adhesion to fresh (unpolymerized) oil films or acrylic paints, if residual surfactants are present.
Aging Characteristics: Accelerated and intensified aging tests of this varnish indicate it resists yellowing and will not become brittle under long term conditions of interior exposure. It will remain soluble, but may require a slightly stronger solvent mixture for removal of a very mature film. Duration under conditions of exterior use depends markedly upon the location and conditions of exposure, as well as the substrata of the painting.
Appearance: Excellent clarity when wet and upon drying.
Applications : May be used as an interior or exterior varnish for acrylic, oil, and alkyd. May be mixed with oils or alkyds to modify viscosity, drying time or improve resistance to cracking. For recommended ratios of MSA Varnish and oil/alkyd paints, please refer to our MSA Gel (Mineral Spirits) Product Information Sheet .
Chemical Resistance: Resoluble in certain strong solvents (mineral spirits, turpentine, benzene and related aromatics, acetone, methylene chloride, ketones, alcohols). Resistant to water and household cleaning compounds.
Coverage: 400-500 square feet per gallon if by brush application; 800-1000 square feet per gallon for spray application.
Drying/Curing Time: Usually becomes tack-free and suitable for recoating after 3-6 hours. Most curing will occur within two weeks
Flexibility: Adequate flexibility to withstand normal handling conditions, including rolling and restretching at room temperature. Like all acrylics, MSA films become more brittle at temperatures below 50 oF, and should not be bent or flexed under such conditions. Withstands expansion and contraction caused by changes in temperature and humidity. ASTM D 522, Test Method B- Cylindrical Mandrel Test at 70 o F., 3.5 mil thick film passes at two inches diameter mandrel.
Gloss Retention: After 1200 hours UVA exposure, MSA Gloss varnish retained 99% of its initial gloss.
Hardness/Mar Resistance: Relative to acrylic paint, MSA yields a harder, lower tack surface, which is much less susceptible to imbedding dirt. ASTM D 3363, Film Hardness By Pencil Test, Scratch Hardness is "HB”.
Satin and Matte finishes are inherently more marable than Gloss varnishes.
Matting Agent: Amorphous Silica
Refractive Index: Using Reichert Abbe Mark 2 Refractometer at 22oC = 1.48
Removability: MSA Varnish is removable with mineral spirits, turpentine or higher boiling point petroleum distillates.
Resin: Solution of isobutyl and n-butyl methacrylate. Thermoplastic.
Solvent: Supplied solubilized in Mineral Spirits.
Specular Gloss: (75 o geometry) as supplied- "Gloss" 95, "Satin" 35, "Matte" 8. Thinning of varnish and absorbent substrate will decrease the sheen.
Thinning: Required prior to use. Start with a ratio of 3 parts varnish to 1 part solvent for brushing; and between 1 and 2 parts varnish per part solvent for spraying. Please see the following Tech Sheet for a list of recommended solvents:
Solvent Compatibility for MSA Varnish
Ultraviolet Protection: Hindered Amine Light Stabilizer and ultraviolet absorber (substituted benzotriazole compound).
Viscosity: Brookfield RV, as supplied; Gloss, 1000-1500 cps; Satin, 2000-3000 cps;
Matte, 2500-3500 cps.
Water Permeability: 1.48 perms. Almost 5 times less porous than the normal acrylic paint film. Will not fog or turn cloudy when exposed to high humidity or low temperature.
The above information is based on research and testing done by Golden Artist Colors, Inc., and is provided as a basis for understanding the potential uses of the products mentioned. Due to the numerous variables in methods, materials and conditions of producing art, Golden Artist Colors, Inc. cannot be sure the product will be right for you. Therefore, we urge product users to test each application to ensure all individual project requirements are met. While we believe the above information is accurate, WE MAKE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, and we shall in no event be liable for any damages (indirect, consequential, or otherwise) that may occur as a result of a product application.