Oxy-Acetylene Welding Aluminium – Complete Guide
Many people believe aluminium can only be welded with TIG or MIG. In fact, gas welding aluminium is a proven technique that gives excellent results – provided you have the right equipment, the right filler rod, and the right flux.
Why is aluminium difficult to weld?
Aluminium forms an oxide layer the instant it is exposed to air. The oxide layer melts at around 2,000 °C, while the underlying aluminium melts at around 660 °C – and aluminium gives no colour change as it approaches its melting point. Without the right technique, you burn through before you can see it's hot. The solution has two parts: a flux that dissolves the oxide layer, and a flame with precisely controlled heat delivery.
Why Dillon works so well on aluminium
The Dillon torch runs at an unusually low, steady gas pressure of just 0.5 bar. That gives a soft, concentrated flame with minimal turbulence and a narrow heat-affected zone – exactly the control aluminium demands. You can keep the material at working temperature without the heat spikes that collapse thin aluminium.
Step by step
- Clean thoroughly: Brush the joint with a stainless wire brush (kept solely for aluminium) and degrease.
- Apply flux: Mix your aluminium flux with water into a paste and brush it onto the joint and the rod. The flux dissolves the oxide and shows you when working temperature is reached.
- Setting: Set a neutral, soft flame. Choose the nozzle to suit the thickness – for thin sheet, a small nozzle (0 or 0,5).
- Preheat and watch the flux: When the flux turns glassy and runs, the material is ready.
- Add filler rod: Add filler rod in the correct alloy (see the table below).
- Wash off flux residue: After welding, wash off the residue with hot water – it's corrosive.
Which rod for which job?
| Material | Recommended rod |
|---|---|
| Unknown or mixed alloy, general repairs | Aluminium rod 5% Si |
| AlMg alloys, marine components | Aluminium rod 5% Mg |
| Pure aluminium (99.5 %), soft components | Aluminium rod, pure |
What you'll need
- Dillon Standard Kit or Dillon Pro Kit: – the torch whose low working pressure makes aluminium welding controllable.
- Aluminium flux and the correct filler rod.
- The Rod & Flux Package: – rod and flux for steel, stainless, aluminium and cast iron in one bundle.
- Welding goggles in the correct shade.
Ready to start? See the Dillon Standard Kit here.