Plywood Minimum Bend Radius Design Considerations

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Plywood Minimum Bend Radius Design Considerations

Plywood Minimum Bend Radius Design Recommended

Plywood, after softening, may be bent on a cold ventilated form. The part should be allowed to dry completely on the form. When bending plywood, drying may be hastened by laying a piece of coarse burlap over the radius bending form. To speed drying, a fan may be used to circulate air around the formed Plywood part.

In bending pieces of small radii or to speed up the bending of a large number of parts of the same curvature, it may be necessary to use a heated bending form. The surface temperature of this form may be as high as 149 °C (300 °F), if necessary, without danger of damage to the plywood. The plywood should be left on the heated form only long enough to dry to room conditions.

	At 90° to Face Grain
	At 0° to 45° Face Grain
	At 90° to Face Grain
	At 0° to 45° Face Grain

Plywood Characteristics		10% Moisture Bent on Cold Mandrels		Thoroughly Soaked in Hot Water, Bent on Cold Mandrels
Plywood Characteristics		Figure 1	Figure 2	Figure 3	Figure 4
Thickness (inches)	Number of Layer Plies	Minimum Bend Radius (inches)
.035	3	2.0	1.1	0.5	0.1
.070	3	5.2	3.2	1.5	0.4
.100	3	8.6	5.2	2.6	0.8
.125	3	12.0	7.1	3.8	1.2
.155	3	16.0	10.0	5.3	1.8
.185	3	20.0	13.0	7.1	2.6
.160	5	17.0	11.0	6.0	2.0
.190	5	21.0	14.0	7.0	3.0
.225	5	27.0	17.0	10.0	4.0
.250	5	31.0	20.0	12.0	5.0
.315	5	43.0	28.0	16.0	7.0
.375	5	54.0	36.0	21.0	10.0

Reference:
Federal Aviation Administration,
Acceptable Methods, Techniques and Practices Aircraft Inspection and Repair.
Advisory Circular AC 43.13-1B