3M™ Scotch-Weld™ Core Reinforce Adhesive EC-3903

3M™ Scotch Weld™ Core Reinforcement Adhesive EC 3903 is a liquid adhesive designed for use in bonding and reinforcing crushed honeycomb core. This green, organic liquid adhesive is applied via spray. It has a viscosity of 100 300 cps and a flash point of 45°F (7°C). You can also use EC 3909 with 3M™ Scotch Weld™ EC 3703 to reduce viscosity and solids.

What Are Epoxy Adhesives? 

3M™ epoxy adhesives are part of the class of adhesives called "structural adhesives," which also includes polyurethane and acrylic adhesives. Epoxy adhesives are typically formulated with reactive components (Base and Accelerator) that cure when mixed to form a solid plastic material. 3M provides epoxy adhesives in multiple formats to support your processing needs:

Two Part – In this format the Base and Accelerator are stored separately which enables the adhesive to have a long shelf life even when stored at room temperature. These materials are available in a duo pak cartridges for use with the 3M™ EPX™ Applicator System, enabling you to simultaneously meter, mix and apply two part adhesives. For larger scale operations, you can purchase these in bulk. Because these parts are mixed at point of use, you can reduce waste by saving non mixed unused material for a later job.

One Part – In this format, we do the mixing for you and ship it frozen. You store it in a freezer, then remove and thaw it when you’re ready to use it.

Adhesive Films – In this one part format, we not only do the mixing for you, but we also turn it into a film that can be specifically cut to size and placed into your bond line. We offer a variety of films in different weights/thickness and supports. These films must be stored frozen.

In a two part epoxy adhesive, once the two parts are mixed in their specified ratio, they begin the curing process and offer a limited working time where the adhesive can be applied and the two surfaces positioned as needed. Similarly, in a one part adhesive there is a limited out time after which material is thawed during which it must be used. This work life or out time lasts anywhere from a few minutes to 48 hours or longer.

In general, epoxy adhesives provide high shear and peel strengths and have good environmental resistance. These adhesives are preferred for their ease of use, mechanical strength and chemical resistance. Depending on the formulation, epoxy adhesives can be flexible or rigid, transparent or opaque, quick setting or slow setting, high flow or low flow, room temperature or elevated temperature cure. Epoxy adhesives are among the strongest adhesives available, making them well suited for jobs requiring strength and durability.

What is Structural Adhesive Film?

The fewer rivets you have in your aircraft the better. Structural adhesive films enable the designer to get more innovative with their parts, and reduce the overall number of rivets required on your structure. This thermosetting modified epoxy in film form can be used for bonding a wide variety of substrates, including metal, honeycomb and composite. Structural Adhesive Films come in a variety of weights and thicknesses, minimizing the weight while maintaining the structural integrity.

The films are available in supported versions, which are typically used for monolithic bonding or honeycomb sandwich. They are also available in unsupported form for reticulation onto honeycomb. These films can