As shown in the last line of Table 2, the water that you use in your cleaning operations is very important. I strongly recommend that you use deionized water in your shop and not well water or city water. City water can go bad on occasion, whereas having your own water deionizer in your shop is an excellent safety measure. Well water may be great for drinking, but it contains minerals (calcium oxide, magnesium oxides, etc.) that are strong braze-inhibitors.
Equipment for Cleaning
The equipment you use can be simple or formidable, depending on your budget. Cleaning can be done in a simple bowl on your workbench; in a larger, floor-mounted aqueous cleaner (Fig. 1); or perhaps via ultrasonic cleaning methods, such as that shown in Fig. 2. Ultrasonic cleaning baths are probably the most effective means available today for removing surface contaminants. The liquid in the ultra-sonic tank should be a degreasing fluid compatible with the type of oil/lubricant you are trying to re-move.
Proper cleaning of components to be brazed is essential prior to their being assembled together for brazing. Once the parts are assembled for brazing, any contaminants still trapped between the faying surfaces of the joint cannot be effectively removed. This will then prevent successful brazing, resulting in increased re-work, scrap, rejects, failed parts, delays in shipment, increased costs and even a bad reputation in the brazing industry for your shop.
Click here to read parts 1, 2 and/or 3 of this blog series.