Teardrops n Tiny Travel Trailers

When dealing with difficult to bond substrates and critical applications, use of an adhesion promoter or primer can increase adhesion levels and help ensure the best ultimate bond strength. 3M Adhesion Promoter 111 (AP-111) and 3M Primer 94 (P94) are two broadly useful promoters for high strength bonding tapes and form the basis for an easy primer selection system.

When a primer is needed, 3M AP-111 is often a preferred choice because it is isopropyl alcohol based and is quick and easy to use on a variety of surfaces. In some cases, it can be used as a cleaner and primer in one step. This promoter is typically applied by putting on a tissue or clean rag and then wiping the surface in a cleaning motion, followed by wiping any remaining material on the surface dry. The surface is ready for bonding immediately after application assuming the surface is dry.


For 3M Primer 94 and other similar resin based promoters application is typically done by brush, felt tip applicator or similar method. After application, the primer must be allowed to dry, possibly up to 5 minutes depending on air flow and temperature.

3M Adhesion Promoter 111 is generally a first choice for painted surfaces and bare metals. This promoter works on a wide variety of paints and bare metals, the primary exception is textured paints and rough metals where effectiveness can be lower. If the paint surface is relatively clean, consider evaluation of the promoter as a cleaner and primer in one step. For bare metals, cleaning the metal prior to use of the promoter is suggested as any contamination typically found on the metal can interfere with the promoter’s effectiveness.

3M Primer 94 is generally a first choice for plastics, including many low surface energy plastics, and rubber materials. This primer system is somewhat universal in nature and also works on a variety of paint and bare metal surfaces.

While AP-111 is not a first choice broadly for plastics, it has been found to work well on many smooth, hard medium to high surface energy plastics such as: polyester, polycarbonate, acrylic and Nylon®. Many times a promoter is not needed on these materials, but AP-111 can be considered as an option as a cleaner/primer if higher strength is desired.

Below is a quick outline of primer selection by substrate:

Substrate Material: First Choice Alternate
Bare Metal AP-111 P94
Paint and Painted Metal AP-111 P94
High and Medium Surface Energy Plastics P94 AP-111
Low Surface Energy Plastics P94
Rubber P94