Oxy-Acetylene Brazing 3D

Oxy-Acetylene Brazing 3D

This 3D video demonstrates how we do oxy-acetylene brazing for residential HVAC equipment. We show how to braze copper at both the air handler and the outdoor unit, and we cover some considerations when brazing and soldering other metals.

Start by removing Schrader cores, which can cause pressure to build up in the system when you flow nitrogen. If you’re working on a system that already has refrigerant in it, you will need to use proper recovery practices.

Before cutting copper, be sure to clean it. Then, ream or deburr the copper tubing to remove the burr. Cutting copper causes a burr to form on the rim of the tubing, which can cause turbulence or deform your flared connections if it stays in the tube. Make sure the burr doesn’t fall in and that you don’t over-ream your copper.

Fit the tubing together and ensure that there isn’t too much of a gap between the male and female ends. If the gap is too large, you risk making a weak connection and ought to consider using reducers or bushings.

First, purge the air from the system with nitrogen. Then, flow nitrogen at 3-5 SCFH, which is a very tiny amount. Before brazing, make sure you have your PPE and a fire extinguisher. Protect components with a wet rag or a heat-blocking putty, like Refrigeration Technologies WetRag.

Your oxy-acetylene torch rig should NOT have any oil on the threads. First, connect the oxygen regulator to the oxygen tank, and then do the same for the acetylene tank. Connect and tighten your hoses to the regulator and torch handle assembly. Make sure you use the appropriate torch tip, including specialty tips in special applications.

Then, close off the regulator adjustments and open the tanks. Bubble-test the connections and hoses to check for leaks in your torch rig. Set the pressure at the regulator with open torch handles, which may vary. Use a proper striker to light the torch; you may light it with acetylene first or with oxygen and acetylene already mixed.

You will want a flame that’s as close to neutral as possible. Carburizing flames have large secondary feathers and have too much acetylene, and oxidizing flames have no secondary feathers and have too much oxygen.

Heat your copper to a dark cherry red color, moving your torch to conduct heat into the joint. That will allow the alloy to be drawn into the joint. You’ll want to make sure you’re flowing nitrogen when you’re brazing copper, as cupric or copper oxide can build up on the inside otherwise. When you’ve finished, shut off oxygen first and then acetylene. In the field, you might shut them off simultaneously as quickly as possible.

Copper is the most common brazing metal, and it can be annealed. It’s also easy to estimate its temperature by color, and it can be fluxed with phosphorus-bearing alloys. However, some “copper” components are actually copper-plated steel, so you have to treat those components as steel when you reach the steel. Brass is softer and often used for cast parts like valves. It has a lower melting temperature and doesn’t conduct heat as well as copper. It’s best to use a high-silver rod with a paste flux (or a flux-coated high-silver rod). Steel is common in compressor stubs. When working with steel, avoid phosphorus-bearing rods. Stick with a high-silver flux-coated rod or a high-silver rod with a paste flux. Aluminum has a low melting temperature and doesn’t give you temperature indicators, so it can be tricky. You will also not use the same alloys or flux you’d use for the other metals. Usually, the flux will be your temperature indicator.

When patching an evaporator coil, you will have to solder aluminum. It’s a good idea to use an air-acetylene torch or MAPP gas torch. Repairs can be done within the coil pack or on the U-bends. Heat the tip of your rod and dip it in the flux. Heat the base material and melt the flux on top of it. Heat the flux until it goes clear and quiet, add the alloy, heat the alloy until it goes clear and quiet, and then pull the torch back. Then, clean off the flux to prevent corrosion.

You can also use an indirect heating method with a separate flux. Heat the base material, apply the flux, heat the flux until it bubbles, and back off and apply the alloy. Pressure-test and bubble-test your system to check for leaks.

When you’ve finished brazing, allow your connections to cool for a bit before cooling them with a wet rag. Inspect your connections with a mirror. If everything looks good, you can add your core remover tools and do your pressure and bubble test in preparation for your vacuum. Again, check your connections with a mirror. You don’t want to see bubbles or microfoam, and you don’t want a pressure drop.

Comments

Most popular videos

See all +
thumbnail

Tips for Cleaning an Air Conditioning Common Drain

thumbnail

Gas Furnace Overview w/ AC Service Tech

thumbnail

Motor Overload and Safeties – Kalos Meeting

thumbnail

A Common Electrical Mistake

thumbnail

5 Traits of Bad HVAC Leaders

thumbnail

Don’t Overfill Refrigerant Recovery Cylinders The Easy Way

thumbnail

How to Replace an AC Condensing Fan Motor

thumbnail

How to Braze Air Conditioning Copper

thumbnail

How to Leak Test an AC With Nitrogen Pressure

thumbnail

How to Properly Pipe a Drain on a Fan Coil

thumbnail

4 Silly Mistakes of The Green HVAC Tech

thumbnail

How to Install an AC Disconnect

thumbnail

Why a Hard Shut Off TXV Closes

thumbnail

The Importance of SST (Evaporator Temperature) and Using a Scale (Kalos Meeting)

thumbnail

Adjusting Gas Pressure on a Standard and Gemini Furnace Valve

thumbnail

How a Heat Pump Reversing Valve Works

thumbnail

Don’t Confuse TD & Delta T

thumbnail

How to Install a Thermostat

thumbnail

How and When to Use a Schrader Core Removal Tool

thumbnail

Why Does The Evaporator Coil Freeze (And How to Diagnose It)

thumbnail

How to Measure Total External Static Pressure (TESP)

thumbnail

Does a TXV Shut under Vacuum?

thumbnail

Prevent this Common Manometer Mistake

thumbnail

Facts About Fusite (Compressor Electrical Pass Through Connections)

thumbnail

See Inside a Biflow/Heat Pump Filter Drier

thumbnail

Flammable Refrigerant Safety Basics – Kalos Meeting

thumbnail

Stuck Contactor Issue

thumbnail

How is 208 volts different than 230/240 volts?

thumbnail

Tips for Hiring & Getting Hired

thumbnail

Open vs. Closed Refrigeration

thumbnail

How is a 3-Phase Motor Different than Single Phase

thumbnail

HVAC Class 11/24/2020 – Electrical Review

thumbnail

How to Measure Gas Pressure – Kalos Meeting

thumbnail

What is Common, Start and Run?

thumbnail

Perfect Flares Every Time w/ NAVAC NEF6LM

thumbnail

Ask Bryan Anything Live Call-in from 11/21/2020

thumbnail

How to Build a Sheet Metal Coil Case From Scratch

thumbnail

What Air Filter is The Best?

thumbnail

Basic Electrical Circuit Terms

thumbnail

The #1 Key to Service Success?

thumbnail

How To Keep Motors Running Cool And Efficient

thumbnail

Talk Through The Refrigerant Circuit Using The “Glass Tube” trainer

thumbnail

Top 10 HVAC Tech Tips for 100K

thumbnail

Installing a Rectangle to Round Transition into an Existing Metal Duct

thumbnail

How Humidity Impacts The Weight of Air

thumbnail

Testing Home Pressure Imbalance w/ Genry Garcia (Spanish)

thumbnail

Some of Bryan’s Favorite New Tools Giveaway Meeting

thumbnail

Bert Teaches The Basic Refrigerant Circuit + Safety

thumbnail

Heat Rise Airflow Calculation

thumbnail

LIVE Apprentice Q&A

thumbnail

Setting a Refrigerant Charge by Subcool

thumbnail

The Toxic SUPER TECH Mindset

thumbnail

Soft Skills Can Be Hard (Disciplines of Growth)

thumbnail

Double Crimp Connection

thumbnail

How to Fabricate a Metal Supply Plenum From Scratch

thumbnail

Delivered Capacity Basics – Kalos Meeting

thumbnail

Sequencer Facts – They Aren’t All The Same

thumbnail

Wire Routing & Float Switch Positioning

thumbnail

Dual Voltage and Part Start 3-Phase Motors

thumbnail

Apprentice Program Day 1 – Using Your Resources w/ Jason Obrzut

thumbnail

Bert Cleans Out His DIRTY Work Van (And You Should Too!) #BERTLIFE

thumbnail

Liquid Line VS. Discharge Line

thumbnail

Tips for Proper AC System Cleaning – Kalos Meeting

thumbnail

EPA 608 Prep – Type 3

thumbnail

Motor Replacement Tips & Tricks – Kalos Meeting

thumbnail

EPA 608 Prep – Type 2

thumbnail

Better Duct Installation Practices – Kalos Meeting

thumbnail

THIS Is How My FIRST WEEK As An HVAC Apprentice Went (I’m Being Trained By WHO?!)

thumbnail

EPA 608 Prep – Type 1

thumbnail

How to Find Refrigerant Leaks – Kalos Meeting

thumbnail

Advanced Ventilation w/ CERV2

thumbnail

Critical System Diagnosis for Residential HVAC

thumbnail

Diagnosing Open & Short Circuits

thumbnail

Installing a Mitsubishi One-Way Ceiling Cassette In An Unfinished Room (You Can See EVERYTHING!)

thumbnail

How to Use a Blower Door (Como usar el Blower Door)

thumbnail

How to Stop Drain Snot (Bacterial Zoogloea)

thumbnail

EPA 608 Core Prep – Part 2

thumbnail

EPA 608 Core Prep – Part 1

thumbnail

A Strange Contactor Issue

thumbnail

GreenSpeed Extreme Install

thumbnail

Symptoms of Low Evaporator Airflow

thumbnail

Preventing Flooding On a Walk-In Call

thumbnail

Symptoms of Overcharge

thumbnail

Diagnosing and Replacing a Run Capacitor

thumbnail

Symptoms of Low Refrigerant Charge

thumbnail

Preventing, Finding & Repairing Refrigerant Leaks

thumbnail

Proper Use of Manometers for HVAC Technicians

thumbnail

UV light and Petri Dish Demo

thumbnail

Tool Talk Live – Probes, Bags, Hand Tools, Power Tools & More

thumbnail

Cleaning BARD units with Venom Packs

thumbnail

Electrical Basic Concepts – RSES NATE Prep

thumbnail

Selling, Upselling, IAQ , Hardstart Kits and More

thumbnail

Cutting & Installing a Rectangle Duct Connection

thumbnail

How to Make a Leak Free Canvas Duct Connector

thumbnail

Cooling Commissioning Measurements Walk Through w/ MeasureQuick

thumbnail

How to Checkout Blower Settings Using a Manometer

thumbnail

Recovery Best Practices & Giveaway

thumbnail

Introduction to the Fieldpiece Joblink Manometer Set

thumbnail

HVAC SCHOOL MONEY TALK – Don’t Make This Common Mistake

thumbnail

Testing out a High Performance HVAC Installation

thumbnail

Commercial Refrigerant Retrofit Options in a Crisis Economy #LIVE

thumbnail

HVAC Myth Busting #2 – Volts Go Down, Amps Go Up

thumbnail

Rectorseal RSH 50 Installation

thumbnail

Setting Up Residential Demand Ventilation with Laser Egg

thumbnail

Residential Zoning Talk #LIVE

thumbnail

DUCTLESS Control and Humidity Hack with Cielo Breez

thumbnail

HVAC Myths and Controversy #1

thumbnail

Rectorseal Surge Protector Installation

thumbnail

HVAC Contractors Guide to COVID-19

thumbnail

Commercial Install Review

thumbnail

DIY Cloth Mask with HEPA Pocket

thumbnail

How to Make an Indoor Air Cleaner the Cheap and Easy Way

thumbnail

Electrical Diagnostic Thinking

thumbnail

Human Comfort Basics – RSES NATE Prep

thumbnail

Introducing Venom Packs

thumbnail

5 Install Mistakes that Kill Systems

thumbnail

UV Part 2 – Honest UV Facts from a Manufacturer

thumbnail

UVC Air Purification – Live Podcast Part #1

thumbnail

How to Make a Metal Duct Transition in the Field

thumbnail

Reversing Valves (RSES NATE Prep)

thumbnail

Sunday Coil Cleaning #BERTLIFE

thumbnail

Liquid Line Solenoid on Long Refrigerant Lines

thumbnail

Condensing Unit Install Practices (RSES NATE Prep)

thumbnail

HVAC Motor Types (RSES NATE Prep)

thumbnail

Relative Humidity in the Supply Air Stream

thumbnail

Advanced Combustion Analysis (HVAC) w/ Jim Bergmann

thumbnail

Advanced MeasureQuick Diagnosis w/ Jim Bergmann

thumbnail

How to Flow Nitrogen While Brazing

thumbnail

Compressor Tear Down (Don Gillis / Trevor Matthews)

thumbnail

Compressor Facts and Troubleshooting (Don Gillis / Trevor Matthews)

thumbnail

CO2 101 (with Don Gillis)

thumbnail

Nikki Krueger – The Dripping Point

thumbnail

Inside a Scroll Compressor

thumbnail

Troubleshoot a Grounded (Shorted to Ground) Compressor

thumbnail

Using Power Factor to Check Capacitors Under Load

thumbnail

Straight Cool Air Conditioning Schematic (Carrier)

thumbnail

Charging During Low Outdoor Ambient w/ Charging Jacket

thumbnail

Recovery Machine Speed Race 🏁NAVAC NRDD Digital vs. Appion G5 Twin

thumbnail

Is There Mold in my Ducks! 🦆(Ducts)

thumbnail

Inside a Sequencer

thumbnail

A thermostat miswire and distracted diagnosis #BERTLIFE

thumbnail

Cleaning large coils with CoilPro

thumbnail

Smelly Ductless #SOLVED

thumbnail

Inductive Reactance in Real Life

thumbnail

50K Subscriber Special & Behind the Scenes Tour

thumbnail

Compressor Won’t Run Diagnosis

thumbnail

A Blower and Heat Strip Dangerous Mistake

thumbnail

How to adjust a TXV, TEV or TX Valve

thumbnail

5 HVAC/R Terms That Sound Worse Than They Are

thumbnail

Fieldpiece Joblink Firmware Update Demo

loading

To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from