Pipefitting Best Practices
This podcast is based on a Kalos meeting about pipefitting best practices, particularly in commercial refrigeration applications. It begins with a few words about quality workmanship by the Kalos founder and CEO, Robert Orr.
Pipefitting consists of repairs and joining metals; when joining metals, we need to liquify the alloy and draw it into the joint via capillary action. When pipefitting, oxygen can present some problems by coating the inside of the pipe with oxides that can contaminate the system. We can reduce the likelihood of oxide formation by flowing nitrogen while brazing; purging nitrogen displaces the oxygen in the lines before brazing, and flowing keeps oxygen out during the brazing process.
Tip selection will be based on the piping diameter; tips that are too small won't adequately heat the pipe, and tips that are too large will consume too much fuel. You'll also need to leak-check your torch tanks and ensure that you have the appropriate ratio of oxygen to acetylene by aiming for a neutral flame rather than a carburizing or oxidizing flame.
After brazing, we need to perform a nitrogen pressure test to ensure that the system is leak-free. Then, once the pressure test is passed, we should evacuate the system to keep the system clean, dry, and tight.
Bryan, Matthew, Roman, and Nathan also cover:
- Brazing vs. soldering
- Properties of base metals
- Alloy properties and appropriate uses
- Mineral oil vs. POE oil and cupric oxide
- Safety practices and PPE
- Preparing copper (sealing, deburring, etc.)
- Valve seating
- Penetration and the gaps between surfaces
- Base metal temperature indications
- Advantages of nitrogen for pressure testing
- Vacuum pump best practices
- Micron gauges
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