{"id":28460,"date":"2026-09-28T20:14:20","date_gmt":"2026-09-28T17:14:20","guid":{"rendered":"https:\/\/artrestorationsupplies.gr\/?p=28460"},"modified":"2026-09-28T20:14:25","modified_gmt":"2026-09-28T17:14:25","slug":"epilogi-kollas-syntirisi","status":"publish","type":"post","link":"https:\/\/artrestorationsupplies.gr\/en\/epilogi-kollas-syntirisi\/","title":{"rendered":"Choosing an adhesive in conservation: B-72, BEVA 371, Plextol\/Dispersion K, Klucel G, Tylose, starch paste \u2013 a comparative guide"},"content":{"rendered":"

Choosing an adhesive is one of the most critical decisions in a conservation treatment. The adhesive must not only \"hold\": it must be compatible with the material of the object and have a mechanical strength less than or equal<\/em> than that of the original, so that under stress the join fails rather than the work; it should age without yellowing or hardening and \u2013 as far as possible \u2013 be removable in the future. In this guide we compare the most widely used conservation adhesives: Paraloid B-72, BEVA 371, acrylic dispersions of the Plextol \/ Dispersion K type, Klucel G, Tylose (cellulose ethers) and starch paste<\/strong>.<\/p>\n

The concentrations and temperatures given are indicative, as found in the literature and in manufacturers' technical data sheets. Always test before applying to an object.<\/em><\/p>\n

Selection criteria<\/h2>\n

Before opening any container, answer five questions:<\/p>\n

    \n
  1. What is the substrate?<\/strong> Porous or solid, hydrophilic or hydrophobic, sensitive to water, solvents or heat?<\/li>\n
  2. What is the role of the adhesive?<\/strong> Structural bonding, consolidation of flaking, reinforcement lining (lining, mending), temporary protection (facing)?<\/li>\n
  3. Which activation medium can the object withstand?<\/strong> Water, organic solvent or heat?<\/li>\n
  4. How will it be removed in future?<\/strong> With which solvent or method, and with what risk to the original?<\/li>\n
  5. What environment will it be exposed to?<\/strong> Temperature, relative humidity, light. An adhesive with a low glass transition temperature may \"flow\" in warm display cases.<\/li>\n<\/ol>\n

    Comparison table<\/h2>\n\n\n\n\n\n\n\n\n\n\n
    Adhesive<\/th>\nChemical nature<\/th>\nMedium \/ activation<\/th>\nTypical use<\/th>\nReversibility<\/th>\nMain limitations<\/th>\n<\/tr>\n<\/thead>\n
    Paraloid B-72<\/strong><\/td>\nEMA\/MA acrylic copolymer<\/td>\nAcetone, esters, aromatic solvents; 10\u201320% or up to 40\u201350% w\/v as an adhesive<\/td>\nCeramics, glass, stone, metals, archaeological material; consolidation 3\u20135%<\/td>\nVery good in solvents<\/td>\nTg ~40 \u00b0C, creep under heat; solvent toxicity<\/td>\n<\/tr>\n
    BEVA 371<\/strong><\/td>\nEVA blend with resins and wax<\/td>\nSolution in hydrocarbons or film; heat activation at about 65 \u00b0C<\/td>\nLining of paintings, consolidation, strip-lining, facings<\/td>\nGood with heat and aliphatic\/aromatic solvents<\/td>\nRequires heating; not suitable for heat-sensitive materials<\/td>\n<\/tr>\n
    Plextol B 500 \/ Dispersion K 498 \/ K 360<\/strong><\/td>\nAqueous acrylic dispersions<\/td>\nWater (dilution); once dry, no longer water-soluble<\/td>\nConsolidation of wall paintings, lining, binder, heat activation of dry film<\/td>\nLimited: swelling\/dissolution in organic solvents<\/td>\nSurfactants and additives; not reversible in water<\/td>\n<\/tr>\n
    Klucel G<\/strong><\/td>\nHydroxypropyl cellulose<\/td>\nWater and<\/em> ethanol\/isopropanol; usually 1\u20135%<\/td>\nPaper, leather, parchment, consolidation of water-sensitive inks<\/td>\nVery good in water or alcohol<\/td>\nLow structural strength; sensitivity to light\/heat in some studies<\/td>\n<\/tr>\n
    Tylose MH (Methylcellulose\/MHEC)<\/strong><\/td>\nCellulose ether<\/td>\nWater; usually 1\u20135%<\/td>\nPaper, textiles, paint consolidation, cleaning gels<\/td>\nVery good in water<\/td>\nSlow drying, lower adhesion than starch paste<\/td>\n<\/tr>\n
    Starch paste (wheat \/ rice)<\/strong><\/td>\nNatural polysaccharide<\/td>\nWater, cooked; diluted during application<\/td>\nPaper repairs, hinges, linings with Japanese paper<\/td>\nVery good in water (and with amylase enzymes)<\/td>\nBiological attack at high RH; limited shelf life once cooked<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    The adhesives one by one<\/h2>\n

    Paraloid B-72 \u2013 the \"standard\" adhesive for solid and archaeological materials<\/h3>\n

    A thermoplastic acrylic resin with excellent chemical stability. For bonding ceramics and glass, a 5\u201310% primer on the edges and a 40\u201350% adhesive in acetone are usually used, following Koob's method (1986). As a consolidant, at 2\u20135%. Its main limitation is its relatively low Tg (around 40 \u00b0C): with heavy fragments or in warm environments, creep may be observed. Detailed information can be found in the Paraloid B-72 user guide<\/a>.<\/p>\n

    BEVA 371 \u2013 heat-activated adhesive for paintings<\/h3>\n

    Developed by Gustav Berger in the 1970s for lining paintings. It is a blend of ethylene-vinyl acetate (EVA) copolymer with resins and wax, in a hydrocarbon solution. It is applied by brush or spray, the solvent is allowed to evaporate and it is activated by heat \u2013 the manufacturer states an activation temperature of about 65 \u00b0C (with a heated spatula, lining iron or vacuum table). It is also available in the form of film<\/strong> (ready-made, uniform thickness), gel<\/strong> and aqueous dispersion (D-8-S)<\/strong>. It is removed with heat and with aliphatic or aromatic solvents (e.g. the special Diluent 372). It is not recommended for materials that cannot tolerate heating (e.g. certain waxes, heat-sensitive varnishes, certain modern materials).<\/p>\n

    Acrylic dispersions (Plextol B 500, Dispersion K 498, K 360)<\/h3>\n

    Aqueous dispersions of acrylic polymers. Their great advantage is that they are thinned with water (no toxic solvents) and form a flexible film. After drying, however, do not redissolve in water<\/strong>; they can only be swollen or removed with organic solvents, and often not completely from porous substrates. They are used for consolidating wall paintings and mortars, as binders in fill materials and \u2013 as a dry film \u2013 as heat-activated adhesives in linings. Dispersion K 360 (successor to Plextol D 360) gives a soft, permanently tacky film, while K 498 gives a harder one. Note: commercial products contain surfactants and additives that may migrate; the composition of several products has changed over the years, so consult the current technical data sheet.<\/p>\n

    Klucel G (hydroxypropyl cellulose)<\/h3>\n

    The cellulose ether with the unique property of dissolving in both water and polar organic solvents<\/strong> (ethanol, isopropanol). This makes it invaluable when the object cannot tolerate water: consolidation of red rot on leather, consolidation of sensitive inks, reshaping parchment, pre-coated Japanese papers activated with alcohol. It is usually used at low concentrations (about 1\u20135%). Its adhesive strength is moderate, so it does not replace starch paste in structural paper repairs. It is available in different viscosities (e.g. E, G, H).<\/p>\n

    Tylose and methylcellulose<\/h3>\n

    Methyl and methyl hydroxyethyl celluloses (e.g. Tylose MH 300) dissolve in water and give stable, neutral solutions. They are used as a paper and textile adhesive, as a paint consolidant, as a thickener for gels or poultices, and in mixtures with starch paste to extend working time and reduce stiffness. Usual concentrations: 1\u20135%, depending on the viscosity of the grade. Preparation: the powder is dispersed in hot water and then cold water is added while stirring, or it is left to hydrate overnight.<\/p>\n

    Wheat and rice starch paste<\/h3>\n

    The traditional adhesive of paper and book conservation, with a long history of safe use. It is prepared from pure starch (gluten-free, such as Japanese Jin Shofu) by cooking in water; the usual starch:water ratios range from about 1:4 to 1:10 by weight, and the paste is then sieved and diluted during application. It gives a strong yet flexible bond, is removed with water (and, where necessary, with amylase enzymes) and ages without significant yellowing. However, cooked paste deteriorates within a few days; prepare small quantities. In a high-humidity environment there is a risk of microbiological attack.<\/p>\n

    Practical selection scenarios<\/h2>\n