ES-6228 Structural Adhesive

General Description

ES-6228 is generally referred to as “Structural Adhesive” or “Structural.” Gray in color, it has the viscosity of molasses. Primarily used to join two or more preformed parts; i.e. bulkheads to fuselage, potting bushings, etc.

The adhesive is structural and can be used in applications where tensile and/or compressive loads are critical. Specifications are listed below. If used per the directions, the bond is probably stronger than the glass or aluminum parts.

Original Velocity plans called for microglass or flox as a bonding agent for preformed parts. Microglass and flox are acceptable alternatives wherever Structural Adhesive is called for. Around 2000 Velocity began using ES-6228 to install channel ducts and bulkheads. It quickly became a favorite and is now prescribed for almost all parts bonding.

Although sold by PTM&W as a Metal Bonding Adhesive, it has excellent glass-to-glass and metal to glass properties.

Velocity Use

Mix 1:1 by weight or volume. It has a distinct if not objectionable odor. It is inherently sticky and will get on any and everything it can. Neat working methods are rewarded.

Mixed per directions, the adhesive will sag or run if applied in moderate quantities. It can be mixed with Cab-o-sil to thicken. Flox or Milled Fiber may be added to give the adhesive more body.

Bonding surfaces should be abraded and cleaned. Brush on a thin coat of straight ES-6228 on all bonding surfaces. A generous amount of adhesive is applied to one of the bonding surfaces. A wedge shape is desirable for most joints as excess adhesive will smoosh from the sides and will create an airtight, bubble free joint.

Press parts together. Use clamps, clecos or pop-rivets to hold parts in place during cure. Clecos must be removed within 24 hours.

Remove excess adhesive while still wet. It will require grinding after cure. Wet adhesive can be cleaned off with Acetone and a cloth. It is OK to run the Acetone cloth directly over the fresh joint.

The following information is from PTM&W’s website:[1]

Product Description

ES6228 is a thin paste viscosity epoxy adhesive designed to provide good bonds to metal surfaces. A unique feature of ES6228 is its ability to bond to slightly oily metal surfaces. This is useful in situations where the complete removal of residual mill oil on metal surfaces is not possible. The thin paste consistency of ES6228 wets the metal surface well for good adhesion. This viscosity also provides some gap filling capabilities, so "close fitting" joints are adequate, and matched-metal joints are not required.

ES6228 has a 1 to 1 mix ratio by weight or volume, for easy measuring. The white resin and black hardener combine to a smooth gray system that is easy to mix and apply. The cured material has very good properties, with high bond strength and elongation, for tough, durable assemblies.

Product Specifications

ES6228 A ES6228 B ASTM Method Color White Black Visual Viscosity, @77oF, centipoise Thin Paste Thin Paste D2392 Specific Gravity, gms./cc 1.32 1.30 D1475 Mix Ratio, By Weight 100 : 100 By Weight or Volume PTM&W Pot Life, 4 fl. Oz. Mass @ 77oF 2 hours D2471

Packaging Weights

Quart Gallon Pail ES6228 A 2.25 lb. 9 lb. 45 lb. ES6228 B 2.25 lb. 9 lb. 45 lb. Kit 4.5 lb. 18 lb. 90 lb.

Directions for Use

PREPARATION: All surfaces to be bonded or patched must be free of dirt, oil and grease. The ability of ES6228 to bond to slightly oily surfaces should be considered as "insurance" for a good bond, rather than justification to avoid adequate surface preparation. The better the surface prep, the better the results! Sanding or roughening the area to be bonded in creases the surface area and enhances the bond. See PTM&W Bulletin "Guide lines for Metal Surface Preparation" for more in formation.

MIXING: Measure out equal parts of ES6228 A and B, combine, and mix thoroughly until a uniform gray color and consistency is reached. Mix for at least 1 to 2 minutes, scraping the sides and bot tom of the container to avoid leaving un mixed material that will cause soft spots in the cured material.

APPLICATION and CURING: Apply mixed material to roughened area of the parts to be bonded. Press surfaces firmly together and let set for 24 hours or more at 75oF. If necessary, place assembly in a jig or other device to prevent movement during initial curing time. Curing time is 24 to 36 hours at 75oF, or 2 hours at 140oF. The material to be bonded may be preheated to accelerate curing time, or very light heat can be applied after the parts have been bonded.

Typical Mechanical Properties

ES6228 A/B ASTM Method
Mix Ratio, By Weight or Volume 100 : 100 PTM&W
Gel Time, @ 77oF 2 hours D2471
Color Gray Visual
Mixed Viscosity, @77oF, centipoise Thin Paste D2393
Cure Time, 24 - 36 hours @ 77oF, 24 - 36 hours @ 140oF
Cured Hardness, Shore D 83 Shore D D2240
Specific Gravity, grams, cc 1.30 D1475
Tensile Strength, psi 9,500 psi D638
Elongation at Break, % 8 % D638
Compressive Strength, psi 12,000 psi D695
Aluminum to Aluminum Tensile Lap Shear 3,480 psi @ 77oF, 3,150 psi @ 140oF

Safety and Handling

PTM&W epoxy products are made from raw materials carefully chosen to minimize or even eliminate toxic chemicals, and there fore offer the user high performance products with minimum hazard potential when properly used. Generally, the PTM&W epoxy resins and hardeners will present no handling problems if users exercise care to protect the skin and eyes, and if good ventilation is provided in the work areas. However, all epoxy resins and hardeners can be irritating to the skin, and prolonged contact may result in sensitization; and breathing of mist or vapors may cause allergenic respiratory reaction, especially in highly sensitive individuals. As such, avoid contact with eyes and skin, and avoid breathing vapors. Wear protective rubber apron, clothing, gloves, face shield or other items as required to prevent contact with the skin. In case of skin contact, immediately wash with soap and water, followed by a rinse of the area with vinegar, and then a further wash with soap and water. The vinegar will neutralize the hardener and lessen the chances of long term effects. Use goggles, a face shield, safety glasses or other items as required to prevent contact with the eyes. If material gets into the eyes, immediately flush with water for at least 15 minutes and call a physician. Generally, keep the work area as uncluttered and clean as possible, and clean up any minor spills immediately to prevent accidental skin contact at a later time. Keep tools clean and properly stored. Dispose of trash and empty containers properly. Do not use any of these types of products until Material Safety Data Sheets have been read and understood.