How to Remove Brazing Residues from Metal Tubing
Ultrasonic cleaning is a fast, effective way to remove residues deposited when brazing or soldering end fittings to stainless steel metal tubing used for fuel lines and brake lines. Residues left on external surfaces may attract dirt and in some instances may attack the metal. Residues that penetrate to the inside of metal tubing and fittings joints could damage brake and fuel mechanisms.
Mechanical or manually cleaning interiors of small diameter metal tubing such as used for fuel and brake lines is almost impossible and definitely time consuming to ensure removal of contaminants. Cleaning with ultrasound solves the problem because cavitation action created by microscopic bubbles reaches all interior and exterior tubing and fitting surfaces immersed in the ultrasonic cleaning bath. As these bubbles implode they remove and carry away contaminants leaving a clean bright surface.
Setting Up a Metal Tubing Cleaning Cycle
The manufacturer of Elma ultrasonic cleaners developed a cleaning cycle that thoroughly cleans and rinses stainless steel tubing and fittings in less than 20 minutes. Actual cleaning time may depend on the condition of the tubing and the number of tubes being cleaned during a cycle. The equipment recommended is the Elma dual-frequency TIH series exemplified by the 5-gallon capacity TIH500MF2 and its separately ordered mesh basket 11.4 x 10.6 x 5.1 inches deep. Larger models of ultrasonic cleaners are available. Contact us for recommendations.
Also contact us for Chem-Crest 55 phosphoric acid-based liquid detergent concentrate. It removes oils, greases, lubricants and oxides and leaves no residue when rinsed after the cleaning operation. Recommended dilution is to 4 to 10% in water; recommended solution temperature is 50 to 60?C.
TIH Ultrasonic Cleaner Features
Cleaning tanks are fabricated of a special grade of stainless steel to provide long service life. An intuitive control panel allows operators to control ultrasonic power from 10% to 100%, thereby tailoring the cleaning to the task at hand. Units are equipped with a thermostat to setsolution temperatures from 30 to 80?C, and a timer variable to 15 minutes or continuous.
The degas function speeds preparation of fresh aqueous cleaning solutions by removing trapped air; the sweep function assures even distribution of ultrasonic energy throughout the solution. This eliminates areas of high and no cleaning action.
TIH ultrasonic cleaners operate at a user-selected 25 or 45 kHz ultrasonic frequency which broadens their capability in the shop. The lower frequency is selected to remove loose metal filings, shavings and polishing compounds; 45 kHz is best for removing grease and other contaminants.
A Representative Cleaning Operation
Here’s a suggested cleaning cycle based on Elma’s recommendations. Experience will guide you in refining it to suit your operations:
- Bath Preparation: Add water to fill the tank half full. Add the correct amount of Chem-Crest 55 concentrate based on the tanks full capacity then continue adding water to the marked filling level on the tank wall. This will correctly dilute the solution and allow you to adjust the solution level by using the drain valve due to displacement by tubes being cleaned. Turn on the unit on using the timer dial set to 10 minutes and set the function dial to degas. This mixes and degasses the solution. When degassing is complete you can turn the unit off until you are ready to clean.
- Cleaning Preparation: Turn the heater switch on and set the thermostat to 50?C. Set the function dial to sweep and the frequency dial to 25 kHz. Carefully position the stainless steel tubing-end fitting assembly in the mesh basket at a slant to provide solution access to internal surfaces. You may need to collect excess solution into a container using the drain valve.Note: long tubes may require support at the other end. Set the power to 100%.
- Cleaning Cycle: Turn the unit on using the timer dial set to 15 minutes. Periodic raising and lowering the basket will improve solution circulation to clean interior surfaces, but wear gloves when doing this.
- At the end of the cycle transfer the tubes to a shower rinse for about one minute to remove residues from interior and exterior surfaces.
When cleaning efficiency drops drain the tank. Dispose of the contents in an approved manner. Take the time to clean the tank following maintenance instructions in the user manual. Mix and degas fresh solution and you’re ready to continue.
For more information on other uses for the TIH ultrasonic cleaners or for help in solving your cleaning challenges contact the iUltrasonic experts at 973-440-2191.
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