Chris Paschke - Beva 371® Film, Testing and Application

Yes, another article on the ever disappearing materials from our industry, and the substrates it is mounted to. All of the Film 4000 I located is gone in less than a year and since there is no sign of any version of a Film 4000 replacement, research needed to be done on other alternatives of adhesive that might fill the void. Aside from wet/dry mounting with EVA (ethylene vinyl acetate), or pressure-sensitive mounting with Gudy 870, there has been a transparent permanent PSA film hiding in plain sight…Beva 371 Film.

BASF (Baden Aniline and Soda Factory) was established in 1865 in Mannheim, Germany, and at the time produced dyes, as well as the necessary inorganic chemicals, and today is the largest chemical producer in the world with subsidiaries and ventures in over 80 countries. When Gustav A. Berger developed BEVA® 371 [solution] in 1970 he was obtaining some of his ingredients [for Beva] from BASF, and he realized that some of the components may become unavailable in the future.

In the 1990's, Berger identified new components that could replace any of the 5 existing compounds in BEVA 371 when he needed them, so when Laropal K80 (formerly Ketone N) was discontinued by BASF in 2008, aldehyde ketone resin was chosen to replace it, maintaining adhesive strength and elasticity. The reformulated adhesive was developed between 2009-2021 and was designated BEVA® 371b. It was slightly more yellow than the original formula because the new resin was more yellow, but when Laropal K80 went out of production, the 2021 replacement Laropal A81 eliminated the previous yellow with its clear/white color and Beva® 371a was born.

Originally only available as a gallon liquid, Beva 371 solution has been converted as a pure 371 solution into film form for easy workability without the use of flammable solvents, and in applications where liquid Beva may not be suitable. Since its development as a film it may soon be the only heat-activated film available. It is transparent, smooth, non-toxic, non-flammable, does not trap air; and heat activates with a tacking iron, house iron (at polyester temperature setting), vacuum table, or dry mount press, and is most frequently used for relining deteriorating or torn canvases with a new structural substrate.

An MSDS states that the adhesive is a solid polymer film composed of four major elements: Ethylene Vinyl Acetate (EVA) Copolymers Cyclohexanone resins, Phthalate Ester of Hydroabietyl Alcohol, and Paraffin; all of which ensure flexibility, good adhesion, tackifiers for initial stickiness, and lower bonding temperature. these elements allow for it to bond well on assorted paper textures and weights, fabric, canvas, textiles, wood, metal, plastic, and boards making it well suited for relining paintings, mending tears, bookbinding, textile and leather conservation, and creative applications.

It comes in 27” and 54” wide rolls at 1 mil and 2.5 mils. The roll appears to be composed of two materials rolled together, one of which contains the Beva 371 Film, the other a release liner. The white paper is a silicone coated paper; this is the release layer. The other clear sheet is a polyester (Mylar) film, one side of which has been coated with the Beva 371 adhesive. The side of the clear sheet facing the release paper is the adhesive side, which may be verified as slightly tacky and scrapes with a fingernail. (photo 1) Once mounted it is removable using hexane or acetone, or by heat, though adhesive residue will remain.

202512_01 Photo 1
Beva film is sandwiched as opaque white 4mil silicone coated release paper, adhesive attached to a sheet of 1.5mil Mylar release film (Release paper + Adhesive + Mylar release film).

Beva is perfect for relining delicate posters and torn canvases, but wait, there is more. The first step was to determine all the basics for this adhesive including what it will mount to tear strength, as well as basic time and temperature tolerances, whether it could be used in dry mount presses, and if it adapts to creative applications. It was basically tested using a mechanical press set at 150°F for 15 seconds and 1 minute, and 175°F for 1 minute, using a folded single-sided commercial release paper envelope and no release board. (photo 2) On to what will bond and at what time and temperature. Assorted papers, decorative papers, fabrics, digitals, photos, and encapsulated charts were tested, and—though small—remarkably they ALL mounted at 150°F in 30 seconds. (photo 3) Even the very thin, sheer Asian kinwashi and mulberry papers, polyester encapsulate, glassine, vellum with graphite on the back, and Tyvek all mounted perfectly.

202512_02 Photo 2
An open edition Wild Apple print was test mounted in a 210-X mechanical press at 150°F for 15 seconds, 1 minute, and 175°F to ³⁄₁₆” foamboard resulting is excellent tear strength bond.

202512_03 Photo 3
(L to R) Panel 1 – 40# Lineco, 30# Ragston, 90# Stonehenge, 140# and 256# rough watercolor; Panel 2 – Felt, Raw canvas, Ultra Suede, Linen, Burlap, Papyrus, Amate Bark paper; Panel 3 – Encapsulated map, 1ply embossed accent strip, Xerox digital print, dye sub digital canvas, Epson digital canvas, digital photo. All perfect in 15 seconds at 150F.

Since part of the reason we need a clear dry mount film is to apply it to any desired substrate to prevent ghosting, it needed to be tested on black foamboard. (photo 4) At 150°F it was fine, but at a hotter 165°F -175°F for 30 seconds all the decorative Asian papers showed soaking through. Since no testing was done in the 4060 VacuSeal, allowing for the draw time will add time to the process, while the temperature should still stay between 150-175°F. Time and temperature will need to be tested in your unit before using on a real project.

202512_04 Photo 4
Kinwashi, mulberry, glassine, tracing vellum with graphite on back, Tyvek, Unryu dyed black, Unryu thick Chiri/Brown all bonded perfectly at 150°F for 30 seconds with no visible saturation damage. But at 160 - 175°F for 1 minute there was visible saturation of all the porous Asian papers.

Usually it is recommended to apply to the substrate first, but this may change with the application. With the Beva intact, cut the film to size. Separate the clear layer, and lay the tacky side onto the substrate. Using a tacking iron set at 150°F or a house iron set at Polyester, iron the adhesive to the substrate, across top and center down, then out to all edges. (photo 5) Once cooled, peel the Mylar, leaving the adhesive on the surface. (photo 6) Place the material to be mounted on top of the adhesive you have just prepared. Use the silicone coated white paper as a release paper to protect the art. Iron 150°F heat to melt the adhesive between the two layers to adhere. The final mount may be achieved by either hand iron or dry mount press remembering it will take longer to heat up all layers to bonding temperature to activate.

202512_05 Photo 5
A house iron set at Polyester presses the adhesive to a 4-ply black ragboard.

202512_06 Photo 6
Once cool, peel the Mylar liner from the mounted adhesive.

The basic mounting rule of “increase time or temperature, but not both” holds true here too. Beva melts at 150°F but the window is 150°F-185°F. If there are numerous layers or an 8-ply substrate, often the temperature is better for final bond at 175°F, with 2 minutes in a mechanical press. Beva Film easily mounts oversized works because it is premounted to one surface (substrate), and once cooled the Mylar liner is removed. The non-tacky adhesive allows for ease of alignment of the second layer to be mounted.

Creative applications are one of the benefits of pure film dry mount adhesive, so Beva needed to be tested in that venue also. Tiered matting is very profitable but has the option of becoming time intensive when requiring a wet/dry mount with dry mounting making it quick and easy with size and bond—everything at once. Both the mechanical press version for each layer and final bond, as well as manual hand house iron for each individual layer then bonding the final as a unit in the press were tested. Interestingly—once all layers were sized—it seemed simpler and quicker to hand iron the Beva to the back of each separate sheet then mount the unit at 175°F for 2 minutes.

The first sample is a Pin-striped Tiered mat consists of 2 black 4-ply ragboards with 3 sheets of Canson red paper between them. The Beva was applied to the backs of the top mat and three single sheets of paper then to the back mat. (photo 7) The second sample is a Surface Tiered Pin-stripe with Precious Metal Gold and Black Canson atop a 4-ply cream ragmat, 2 more sheets of Black Canson between that and the back 4-ply cream rag. (photo 8) All layers were hand premounted, cooled, aligned, then placed in a release envelope into the mechanical press at 175°F for 2 minutes.

202512_07 Photo 7
This shows the layout of the Pin-striped Tiered mat of 2 black 4-ply ragboards with 3 sheets of Canson red paper between them.

202512_08 Photo 8
This shows the gloss of the premounted Beva that was hand ironed to each layer for a Surface Tiered (Precious Metal Gold and Black Canson) atop Pin-striped Tiered core of 4-ply cream ragmat (top and bottom) with 2 sheets of Black Canson between.

As framers we never throw anything away, especially this Beva. Every scrap could also become the perfect bonding adhesive for a surface decoration. (photo 9) The Canson pink strip was premounted to the Beva then trimmed to size and hand ironed to the surface of the black pin-striped mat. These are great front room samplers to illustrate what you are pitching to a prospective client when they have no idea what you mean by a tiered mat. (photo 10)

202512_09 Photo 9
Scraps of Beva were used to premount cut strips of pink Canson paper to fuse to the face of the tired sample mat above.

202512_10 Photo 10
Completed Tiered mat samples 1 and 2. These are great front room samplers to illustrate what you are pitching to a prospective client when they have no idea what you mean by a tiered mat.

The price difference between Beva and Film 4000 is significant, but the composition and applications are much improved. Anytime a product comes along that fills a void and can make a job more predictable and dependable, it should be considered. And as with any service offered, the charge should always reflect the hard costs by increasing the mounting charges to cover the upgraded adhesive.

Beva and all of its benefits outweigh the investment. It's “custom framing” and when creating or repairing someone's treasure, doubling or tripling the mount charge will not likely impact the sale…it's custom.

For more articles on mounting basics look under the mounting section in Articles by Subject.
Additional information on all types of mounting is found in:
The Mounting and Laminating Handbook, Second Edition, 2002,
The Mounting And Laminating Handbook, Third Edition, 2008 and
Creative Mounting, Wrapping, And Laminating, 2000 will teach you everything you need to know about getting the most from your dry mount equipment and materials as an innovative frame designer.

Chris A Paschke, CPF GCF
Designs Ink
Designs Ink Publishing
785 Tucker Road, Suite G-183
Tehachapi, CA 93561
P 661-821-2188
chris@designsinkart.com

Paschke Online

Designs Ink Publishing Article Archive and Reference Library

Articles by Chris A. Paschke, CPF GCF

"Beva 371® Film, Testing and Application"

December 2025