Q&A for How to Braze Aluminum

For refrigeration pipes, it's best to fit another pipe with a larger diameter between the 2 pieces of copper to create a sleeve. You do need to use flux with copper pipes. Apply the flux along the joint where the larger pipe meets the 2 thinner pipes, and use a silver welding or brazing rod to seal the 2 joints.

Yes, but you need a really strong brazing rod that will heat through the anodized layer. Anodized aluminum is essentially aluminum with another layer of metal on it, so the rod has to be strong enough to heat through the anodized layer and reach the aluminum. It's usually safer to weld anodized aluminum at a higher temperature to ensure that you penetrate the anodized layer.

Worse, as the temp required is too high for the aluminum. Use the correct rods for the job.

Add flux by dipping the filler rod into the flux. You may also use flux-coated rods to eliminate this step. The flux-coated rods apply the flux during the aluminum brazing process. Heat the repaired area with a propane or acetylene torch until the aluminum shows an orange bloom.

Aluminum rods. Then there's brazing, which is like thin strips of aluminum 1/8 wide x 12". You'll also need flux. Make sure the material you weld is clean and clear of debris or oils.

Aluminium does not necessarily "rust", but it corrodes. When iron or steel corrodes, it is commonly called "rust". There is no specific name for the material that appears when aluminium corrodes.