Fishing and Gear Technology

Unit 2 - Fishing gear materials

2.4.3. Burning test

The changes in the material when it is nearer the flame and after removal from the flame are noted. For this test only a clean flame and two forceps are needed. The best source of flame is a Bunsen burner. Alternatively alcohol lamp or even a cigarette lighter can be used. A piece of netting material is bought near the flame and then removed. The melting and burning patterns and the nature of the residue produced if any are observed. In the early days of the introduction of synthetic fibres into fishing the burning test was very often used by fishermen as it is the simplest test for distinguishing synthetic fibres from cotton. Vegetable fibres and most of the man-made fibres made of regenerated cellulose burn rapidly in the flame and continue burning after removed from the flame. They have an afterglow, the smell of smoke is similar to that of burning paper and the residue consists of a small amount of fine ash. The synthetic fibres being thermoplastic shrink and melt in the flame; the melting substance drips from the flame, mostly forming a bead or a hard irregular residue.

	PA 6.6 and PA 6	PES	PE	PP	PVC	Saran	PVA(A)
In flame	Melts and then burns with light flame.White smoke, Drops of yellowish melting drip down	Melts and burns with light flame. Sooty, blackish smoke, drops of melting drip down.	Shrinks, curls, melts and burns with light flame. Drops of melting drop down	Shrinks, melts and burns with light flame, drops of melting drip down	Shrinks rapidly and melts does not burn, sooty,melts into a crumbling, black substance	Melts and burns with light flame.	Shrinks, curls and burns very rapidly with light flame.
After leaving flame	Stops burning if melting drops fall down. Small bead on the end of the sample. Hot melting bead may be stretched into fine thread	Stops burning if melting drops fall down. Small black bead on the end of the sample. Hot melting bead may be stretched into fine thread	Continues to burn rapidly. Hot melting substance cannot be stretched	Continues to burn rapidly. Hot melting substance may be stretched into fine thread	Hot melting substance cannot be stretched.	Stops burning immediately. Hot melting substance may be stretched into fine thread	Continues to burn rapidly. Melting substance cannot be stretched
Residue	Hard, round, yellowish bead; not crushable	Hard blackish bead; not crushable	No melting bead; like paraffin; crushable	Hard, round brown to blackish; not crushable	Hard, blackish, crumbly irregular; no bead	Porous, blackish irregular substance; crushable; no bead	Hard, brown to black, irregular; not crushable
Smell of the smoke	Celery-like; fishy odour; faintly like pyridine.	Oily, soot odour; faintly sweet; similar to scaling-wax; aromatic	Similar to burning asphalt; like wax or paraffin	Similar to burning asphalt; like wax or paraffin.	Sharp, sweet; sweetish-sourish	Sharp, acrid	Sharp,sweet like chlorine.

Table shows the reactions to the burning test of the different synthetic fibres by which they can be identified. However, in practice the differences are not always so clear as shown in the table. For an accurate identification it is necessary to verify the results of the burning test by the solubility test and/or the melting point test.