Fiberglass Textiles
Fiberglass Yarn
Code prefix GY
Fiberglass yarn is supplied on bobbins or cones for downstream braiding, weaving, knitting and heavy-duty sewing. It is used to make seals, gaskets and covers on site or by a converter, and to sew the edges of sewn assemblies that must not fail at the seam.
- Continuous
- 500°C
- 932 °F
- Short peak
- 550°C
- 1022 °F
- Construction
- Unreinforced
- GY
Spec sheets are issued against the confirmed grade, with the test method named on the report.
01 — Product description
The input, not the finished part
Fiberglass yarn is supplied on bobbins and cones for braiding, weaving, knitting and heavy sewing. Tex and ply are quoted together because the downstream process sets both: a yarn that braids into a firm packing may be too stiff to sew a cover seam without cutting the cloth.
The same yarn is used to sew the edges of sewn assemblies so the seam belongs to the same temperature class as the cloth. A glass yarn seam on a ceramic cloth cover is a common weak point, and it fails at the stitch line rather than in the fabric.
| Code | Tex | Form |
|---|---|---|
| GY34 | 33 tex | Single ply, bobbin |
| GY68 | 66 tex | 2 ply, cone |
| GY136 | 136 tex | 2 ply, cone |
| GY600 | 600 tex | 3 ply, bobbin |
Storage and handling
- Keep bobbins dry and sealed; moisture affects dielectric behaviour.
- Do not unwind under tension without eye protection.
- Confirm twist direction before setting up a braiding line.
- Specify the sewing yarn separately from the braiding yarn.
02 — Characteristics
Converter supply
Consistent tex and twist for braiding and weaving lines.
Seam strength
The same yarn used to sew cover edges so the seam matches the cloth class.
Dielectric
Suitable for electrical-grade braids and lacing.
03 — Typical properties
Values typical, confirm against duty
| Test item | Value | Note |
|---|---|---|
| Yarn | Continuous filament | |
| Continuous | Static duty | |
| Short excursion | Short term | |
| Tex | Selected by process | |
| Form | Plyed on request |
04 — Standard sizes
| Product code | Dimensions |
|---|---|
| GY34 | 33 tex, single ply, bobbin |
| GY68 | 66 tex, 2 ply, cone |
| GY136 | 136 tex, 2 ply, cone |
| GY600 | 600 tex, 3 ply, bobbin |
05 — Where it is used
- Braided packing and rope
- Sewing high-temperature covers
- Woven tape production
- Electrical lacing
- Gasket reinforcement
Service limits
- Yarn is not a finished seal; twist and ply must match the downstream process.
- Store dry and sealed; moisture affects dielectric performance.
- Use eye protection when unwinding under tension.
Related materials
View family
Fiberglass Yarn
GY