0 items in your basket
Total £ 0.00 EX VAT
MIG Gloves
TIG Gloves
Baseball Caps
Armguards
TIG Heat Blockers
Shop 55,000 Products
SERVICEDEPT.
RAPID BLOG
FEEDBACK
HIRE
Answers to common questions about the mixers, neck tubes, cutting attachments and nozzles used on a hand-held oxy-acetylene torch.
Nozzles are chosen by the bore size that suits the thickness of the metal. Small nozzles suit sheet and light work, and larger ones suit thicker material. Each nozzle size has its own recommended acetylene and oxygen pressures and flow rates, which the maker gives in a chart.Start from the maker's nozzle chart for your torch and the thickness you are joining. A nozzle that is too small struggles to melt or heat the joint, while one that is too large can overheat thin work. If you are unsure, our team can help you choose.
A cutting attachment has two oxygen supplies to the nozzle. One oxygen stream is mixed with acetylene to make the preheat flames, and a separate stream, controlled by a lever, is the cutting oxygen that burns through the heated steel.The cutting nozzle is chosen by the thickness of the material, as the diameter of the cutting oxygen hole is matched to the job. Too little cutting oxygen gives poor slag removal, and too much gives a rough finish. Keep the nozzle at the distance the maker recommends from the plate, as too close or too far disturbs the cut.
A flashback arrestor is designed to stop a flame, using an element such as fine mesh or metal foam that cools it out. Some also have a cut-off valve that operates on pressure or temperature. A non-return valve only controls the direction of flow, so oxygen cannot pass into the fuel line or the reverse. It has no flame-stopping ability.HSE guidance is to fit flashback arrestors, or an equivalent device, at the regulators on both the oxygen and acetylene cylinders, and non-return valves on the torch. Fitting them is not a substitute for safe working practice.
Inspect nozzles regularly and make sure they are not blocked by dirt or spatter. Poorly maintained nozzles cause turbulent gas flow, which increases the risk of flashback. Replace any nozzle that is damaged.Do not hold the nozzle too close to the workpiece, as it can overheat and cause a flashback or backfire. Clean tips with the correct cleaning tools and take care not to enlarge or scratch the bore. If the nozzle seat or mixer is damaged and the connection leaks, replace the part or have it repaired rather than overtightening it.