Basic steps for good brazing

STEP Nº5 POST BRAZING CLEANING PROCEDURE

Once the brazing process is done, the cleaning procedure consists basically of:

• Flux residue removal.
• Surrounding metalic oxide elimination.

When it comes to brazing made under inert atmosphere conditions, or the Gas Flux process, the parts will end clean and shiny. However, when the brazing has been made in open atmosphere, the residue flux is to be cleaned off. A simple warm water wash-up will be required if enough flux has been applied in order to prevent oxides from saturating.

The oxide sturated flux residue is typically dark brown, glassy appearance, and harder to remove. The same happens with residuary flux that has been under excessive heat.

One way to remove these "hard" flux when it's still hot is by carrying out a rust removing and cracking process in warm or acidulus water with sulfuric acid at 10%. This operation requires the brazing filler metal alloy to be completely solidified.

Oxides around the brazed area are easily eliminated using sulfuric or chloride acid at 10%.

Another good way is the use of polishers as the ARGENTA RK 5 for copper and its alloys.

After having the prcedure done, a wash-up with running water will be necessary.

A good cleaning will provide a nice appearance, help localizing design corrections, and allow for easy finishings throught electrolitic process such as zinc, silver, gold, nickeled, among others.

 

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