Processing E-glass Laminates

Cutting

Diamond-coated fibreglass tooling is recommended for best tool life, for example, a jigsaw with a Makita No. 10S Type 150 blade to cut out parts.  The best edge finish is achieved with circular saws running aluminium cutting blades, however blade life is greatly reduced.

Curvatures & Radii

Curved surfaces are achieved without effort by simply kerf-cutting the inside skin. The need for elaborate moulds is not necessary, DuFLEX only needs simple jigs to form a variety of corners and curves.

METHOD A:

Construction of large radii curves

Curves that describe angles of 60 to 90 degrees are achievable with no loss of structural integrity.

Step 1:  A series of narrow parallel slots (kerfs) are cut into the sandwich panel along the inside of the proposed curve, through the facing skin and core to the rear face of the outside skin. The saw cuts should never break through the outer facing skin, which serves as a hinge.

Initially determine the desired internal angle, and outer corner radius. Following the calculations below, will provide the required details on number of slots, and their spacing, to achieve the required curve.

Step 2:  Fill the saw cuts with a thickened epoxy mixture and bend to the final shape and allow to cure.  The shape should be held in position, while the epoxy cures, with clamps or jigs.

Step 3:  An additional layer of fibreglass cloth is applied to the inside of the curve with an epoxy laminating system, covering all the slots and overlapping the end slots by 30 – 40mm.

METHOD B:

Construction of small radii corners

Step 1: A strip of the panel is removed by cutting through the facing skin and core to the rear face of the outside skin. The slot width is calculated by

Step 2: The cut should be filled with a mixture of WEST SYSTEM 105 resin with 206 Slow hardener, modified with 411 Microsphere Blend. This combination will produce a strong, waterproof bond that will hold the curve when cured.

Apply enough modified epoxy to fill the internal angle left by the removed skin and core material. Allow to cure. The shape should be held in position, while the epoxy cures, with clamps or jigs.

Step 3: Fill the internal angle, with a 20mm radius of modified epoxy and allow to cure. Apply an additional layer of fibreglass cloth to the inside of the angle, overlapping the fillet by 25mm on each side.