OLIGOMER
A polymer consisting of only a few monomer units such as a dimer, trimer, etc., or their mixtures.

ONE-OFF
A fabrication process in which a single part is fabricated.

ONE-PART RESIN SYSTEM
A resin system (often used in resin-transfer molding) in which the neat resin and catalyst are mixed together by the materials supplier as part of the resin production operation.

ORANGE PEEL
Backside of the gel coated surface that takes on the rough wavy texture of an orange peel.

ORIENTED MATERIALS
Composites whose constituents are aligned in a particular way.

ORIFICE
An opening, generally referred to regarding spray tip size.

ORIGINAL EQUIPMENT MANUFACTURER (OEM)
Companies that design and build products bearing their name, such as Boeing 777 aircraft of Prince tennis racquets.

ORTHO
Abbreviation for orthophthalic acid type resins and gel coats.

ORTHOPHTHALIC OR ORTHO RESIN
A polyester resin based on orthophthalic acid, also known as a general-purpose resin (GP).

OUTGASSING
Release of solvents and moisture from composite parts under the hard vacuum of space.

OUT-TIME (Out-Life)
The period of time a prepreg material remains in a handleable form and with properties intact outside of the specified storage environment; for example, out of the freezer in the case of thermoset prepregs.

OVEN DRY
The condition of a material that has been heated under prescribed conditions of temperature and humidity until there is no further change in its mass.

OVERLAY MAT
A tissue of staple fibers lightly bonded with a medium, which insures good draping and wetting out in contact resins. It is particularly valuable in masking the veining of strands on the surface of matched metal die moldings.

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Glossary Section (O) Last Updated: 9/3/99 1:10 PM

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