Restoration and trim work calls for the right adhesive for each job, the contact adhesive that bonds new vinyl to a steel door card not being the same product that holds a windscreen rubber to its surround, and neither being the right choice for bonding a headlining to its base. This section covers the principal adhesive families needed for a complete interior, exterior, and trim refit, with the products that the classic-car trade has used for decades, and the correct adhesive type must always be matched to the material being bonded, as general-purpose contact adhesives and household glues lack the flexibility to accommodate the expansion and contraction that occurs with temperature changes in the cabin and will crack and release within a season or two.
Contact Adhesives
Contact adhesives are the workhorse product for interior trim work, applied to both surfaces, allowed to flash off until touch-dry, and then brought together under pressure, a good contact adhesive bonding vinyl to steel, vinyl to vinyl, carpet to a backing board, and felt to a steel shelf with a strong, flexible bond that lasts the life of the restoration. The brush-on and aerosol formulations cover different application requirements, brush-on giving more control on larger panels and flat areas such as the floor panels and transmission tunnel where the precise edge of application is controllable, and aerosol being more practical for awkward shapes, smaller sections, and overhead applications where the spray pattern is the only practical way to cover the surface evenly and where the material needs to be positioned precisely before the adhesive sets. Both formats are formulated specifically for automotive trim application and bond carpet and vinyl to the steel floor without the brittleness or premature failure that general-purpose adhesives produce over time. When carrying out a full retrim, ordering sufficient adhesive at the outset avoids interrupting the job, as running out mid-way through a carpet or headlining installation is a common and easily-avoided frustration.
Headlining & High-Temperature Adhesives
Headlining adhesives are formulated specifically for bonding the headlining fabric to the metal or hardboard support without causing the fabric to discolour, pucker, or sag over time, aerosol headlining adhesive being the typical product, allowing even application across a curved surface. For headlining work a high-temperature contact adhesive is essential, as the headlining can reach significant temperatures in direct sunlight, particularly on the closed cars and on the mid-engined cars where the cabin heats quickly, causing a standard adhesive to soften and the headlining to sag. Surfaces must be clean, dry, and free of old adhesive residue before bonding, and for trim clips with broken mounting points a two-part epoxy adhesive can reinforce the mounting before refitting the clip, while components near an engine cover or other heat source require the high-temperature specification rather than the standard contact adhesive.
Windscreen Sealants & Specialist Bonding
The rubber surround that seals a windscreen or rear window to the bodywork on a classic with a separate rubber surround relies on a sealant applied between the rubber and the body flange and between the rubber and the glass, the correct product being a non-setting butyl-rubber sealant that bonds the rubber to its mating surfaces while remaining flexible enough to accommodate the slight movement that a body and glass undergo through their service life. Using a silicone or polyurethane sealant in this application, the modern body-shop standard for direct-glaze windscreens, is the wrong choice for a classic with a separate rubber surround and is difficult to remove cleanly if the screen needs to come out for any reason. The specialist bonding range covers the niche products, windscreen-rubber lubricants for the initial fitment of the rubber to the body, trim cement for re-bonding loose vinyl on door cards, and the headlining-reinforcement products that strengthen the bond on a refitted hood lining, with the right product for each job avoiding the frustration and rework that comes from using a general-purpose adhesive where a specific one is needed. On the mid-engined cars the floor pan should be treated with sound-deadening material before carpet is bonded down, as the layout transmits more mechanical noise into the cabin than a conventional front-engined car, the adhesive being applied to the top surface of the soundproofing rather than to the bare metal beneath.