Welding with a blowtorch can be a little tricky compared to other types of welding. It requires a blowtorch that is powerful enough to generate both the heat and energy necessary to melt solid metal. It isn’t the same kind of torch you light your crème brûlée with.
So, how do you weld with a blowtorch? Welding with a blowtorch requires a large amount of heat and thermal energy, which requires a potent source of combustible fuel such as oxyacetylene.
Oxyacetylene blowtorches provide a more substantial source of heat and energy than propane or butane and can weld metals such as steel or braze aluminum.
You might not be able to weld with just any blowtorch, but it is possible to weld with the right kind of blowtorch. Keep reading to learn more about braze welding.
You Can Weld with a Blowtorch
There are several common kinds of welding, with tools ranging from handheld arc welding torches to industrial-grade furnace welders that braze every joint on an assembly in one go.
But many people don’t think of blowtorches when it comes to welding for a few reasons:
- Many commonly found utility blowtorches are not powerful enough to melt metals like steel.
- Some propane torches can reach temperatures capable of brazing or soldering brass and silver, but many blowtorches that are commonly found in home utility kits do not generate a high enough heat for welding.
- Electric welding usually achieves a more stable weld with joints that require a high degree of structural integrity.
Despite these marks against them, blowtorches can and are still commonly used in metal fabrication for a variety of different projects and applications.
Can You Weld with a Butane Torch?
Can you weld with a butane torch? No, butane torches do not reach a high enough level of heat and energy to be able to braze or weld metals efficiently.
A butane blowtorch simply does not get hot enough to affect the metal. You have to keep in mind that 90% of a blowtorch’s heat is dissipated through contact with the air, which makes it one of the least efficient welding methods without a shield.
Can You Weld with a Propane Torch?
How to weld with a propane torch? It is easier to weld with a propane torch than it is with a butane torch, though a propane torch is still only suitable for certain types of braze weldings, such as silver solder or brass brazing.
A propane torch doesn’t reach high enough temperatures suitable for welding through fusion.
Note: Do NOT attempt to ignite a propane blowtorch with a butane lighter. Compressed propane is extremely flammable, and the resulting flashback could cause an explosion.
Can I Weld Aluminum With A Propane Torch?
Can I weld aluminum with a propane torch? Yes, you can weld aluminum with a propane torch and aluminum brazing rods as long as it is for non-structural metals that are not weighted or stressed or critical parts.
Propane torches are usually do not reach high enough temperatures to be capable of performing effective aluminum welds.
You might use propane for brazing an aluminum alloy of smaller dimensions or non-critical patches or repairs; however, it is not recommended to use a propane torch for aluminum welding.
Any welding process that uses a flux such as stick welding or flux-cored arc welding is not effective for aluminum welds. The welds created by these methods are too porous for a proper weld.
Gas flames used for welding are not so dependent on their flame temperature but the amount of BTUs they can concentrate in a concentrated work area.
Although propane flames may reach temperatures twice as hot as the melting point of aluminum, aluminum properties make it highly conductive and radiant in relation to heat.
Although some welders claim that repair rods are suitable, the melting point of these repair rods is lower than the aluminum melting point and thus unlikely to result in a proper weld. This is particularly crucial for critical items under weight or pressure.
One of the crucial factors in aluminum welds is the shielding of the weld puddle from contaminants and for this, shielding gas is vital.
There is a reason why professional welders pay for expensive machinery specific to aluminum welds. If welding aluminum was as easy as some say, why would they bother with the expense?
What is MAPP Gas, and Why Can’t I Find It Anymore?
MAPP gas is a fuel mixture that is considered a safer alternative to acetylene in professional blowtorches that is also easier to use.
However, the plant that manufactured MAPP gas discontinued its use after it was discovered that the high levels of hydrogen present in the gas mixture rendered steel welding applications brittle in comparison to other welding gas mixtures.
There are still MAPP gas substitutes on the market that typically consist of stabilized liquid petroleum that has been treated with high levels of propylene.
However, the effectiveness of MAPP gas versus acetylene depends on the types of metal being welded.
The main application for MAPP gas in blowtorch welding is in underwater welding, where it acts as a safer alternative to acetylene (which reacts explosively when exposed to high-pressure environments)
Can You Weld Stainless Steel with a Blowtorch?
While it is possible to weld stainless steel with a blowtorch, electric welding within an inert gas shield is usually a better option for welding steel than a blowtorch.
What is Braze Welding?
Braze welding is a type of welding where, instead of the two pieces of metal being fused at the site of the weld, a filler metal alloy is used to “patch” the two metals together like a sort of glue.
While braze welding is a strong welding type depending on the joints used, it does not require the high levels of heat and energy necessary to fusion weld the two base pieces together.
Braze welding is considered a variant to MIG/MAG welding and is performed by melting a filler metal and then flowing it into the joint of the metal assembly.
Brazing is an excellent welding application where it is not desirable for the metallurgical properties of the base metal to be heat affected by high temperatures.
A significant difference between brazing and welding is that:
- Brazing uses capillary action to fill the space of the metal joint with a metal that has a low melting point.
- Welding uses high-heat fusion to bond each of the metals together.
Both brazing and welding are designed to be permanent methods of bonding two pieces of metal together.
Brazing is a good option for tough metals that are difficult to weld because of the high melting point of the base metal. It’s also a good option for joining two pieces of different types of metals with disparate melting points.
Both brazing and welding are forms of metal fabrication, and the two terms are often used interchangeably, but their adhesive processes are very different.
There are several advantages of brazing with a propane torch:
- They are an inexpensive source of heat and fuel for welding applications in comparison to TIG or MIG set-ups
- They are a clean-burning source of energy
- They are recyclable and environmentally friendly
If your welding project doesn’t require a fusion weld and you can get away with a braze or solder job instead, propane blowtorches can provide a handy form of welding that doesn’t require much technical know-how to pull off.
Torch welding with gas is a much simpler affair than using a TIG rig.
Related reading: Aluminum Brazing: Complete Guide – Advantages Over Welding
Can You Braze Aluminum With a Torch?
Can you braze with a torch? While aluminum is a more challenging metal to weld than some because of its unique metallurgical properties, a bond with aluminum is still possible with a brazing torch if you use aluminum braze.
Most aluminum alloys are capable of being brazed, though propane blowtorches are not capable of reaching the temperatures capable of performing aluminum welds.
How Do Blowtorches Work?
A blowtorch is made up of the following components:
- Fuel gas cylinder
- Oxygen cylinder
- Gas regulators (2)
- Connecting hoses (2)
- Welding tip with igniter
In a blowtorch, the gas regulators are responsible for manipulating the proportion of fuel to oxygen in the fuel-air mixture used to run the torch. These regulators are also responsible for controlling the intensity of the blowtorch flame.
There are multiple kinds of gas-based fuels that are used in blowtorch mixes. The more intense blowtorches necessary to pull off brazing and welding operations are typically operated with acetylene or MAPP gas, while smaller blowtorches operate on propane and butane.
How Hot Does A Blowtorch Get?
How hot does a blowtorch get? The flame temperature of a blowtorch using butane is close to 1,430 °C (2,610 °F). When using propane, the blowtorch temperature is around 2,000 °C (3,600 °F)
Related reading: What Types of Gas Welding Are Commonly Used? | Are they popular?
Supplies for Welding with a Blowtorch
The process of welding with a blowtorch is not that much different from welding with other types of heat applications as far as the process of preparation goes.
To start with, safety should always be observed when doing any kind of high-temperature welding operation.
Be sure to wear protective equipment such as the following:
- Welding helmet, visor, or goggles: Eye protection is arguably the most crucial piece of protective equipment necessary while welding regardless of what method you use since slag burns can heal while blindness from heated particles is often permanent.
- Welding gloves: When working with electric-based welding units, welding gloves provide insulation against electrical shock as well as protection from spatter or slag burns. In blowtorch welding, gloves protect your hands from these dangers as well as ambient heat from the torch itself.
- Welding apron: Everybody thinks they don’t need a welding apron until a pebble of molten slag is burning its way through the front of their shirt. Wearing flame-resistant clothing at the very least is a good idea when performing a weld.
- Welding respirator: Welding respirators are an excellent idea to prevent the inhalation of heavy metals and noxious fumes that are exuded by welding operations.
Protective equipment is necessary to protect the welder from both dangerous fumes and high temperatures. Molten metal can inflict a severe third-degree burn in an instant, so it’s vital to wear layered clothing to prevent a permanent scar or even blindness.
Welding with a blowtorch should take place in a well-ventilated workshop to remove the danger of accumulating fumes.
Be sure to remove any flammable objects or liquids like gasoline or cleaning agents from the workspace area to prevent accidental combustion.
Related reading: Can You Arc Weld Outside? | Understanding welding Outdoors
Make sure that all workspace areas are equipped with fire and carbon monoxide detectors whenever and wherever you work with dangerous fumes and combustible materials.
Blowtorches can emit high levels of carbon monoxide in a small space, and it only takes a small amount of carbon monoxide to poison a welder.
Related reading: How to Start & Grow A Welding Business In 11 Steps
How to Weld with a Torch
How to weld with a torch? Once your workspace is prepared, walk through the following procedure to conduct a blowtorch weld:
- Clean the metal pieces that are going to be brazed together. First, wipe away any surface-level dirt and debris, then use an abrasive cloth or stainless-steel wool to scrub away any harder-to-remove particles. Wipe down the metal with acetone or a similar cleaning agent to remove any oils or grease from the metal’s surface that may be difficult to detect with the naked eye.
- Add flux to the welding site to increase the quality of the resulting weld and prevent unnecessary defects in the weld joint that may result from heating inconsistencies or outside contaminants. A chemical flux can be added to the welding site, or a shielding flux can be used in the form of argon gas.
- Prepare the fuel and oxygen mixture on the blowtorch tank until the blowtorch glows with a bright blue flame. The blue coloring indicates a flame that is burning high enough to braze metal effectively. In a welding torch, the tip of the blue part of the flame is the hottest part of the torch (making it the most appropriate point of contact for an efficient weld).
- Move the flame in a steady circular motion until a small pool of molten metal is created at the designated welding site. Be sure to keep the flame close to the weld site to reduce the number of heat-affected areas surrounding the weld. If brazing, hold the filler rod to the blowtorch at the weld site until a weld pool is formed.
- Using the blowtorch, move the molten filler metal along the weld joint until the two metal pieces are effectively fused via capillary action. If any additional filler material is needed for more significant welds, get additional filler rods to make up the difference until the gap between the two base metals is filled.
- Move the blowtorch in a continuous smooth line down the length of the welding seam, adding filler rod in even increments to create a consistent bead. Allow the weld seam to cure and harden overnight before testing the joint under load.
Unlike propane blowtorches, blowtorches that run on acetylene burn hot enough that they can be used for fusion welding applications.
In torch welding with acetylene, filler metals are still typically added to make the resulting weld more robust or more stable, further blurring the line between a braze and a weld when it comes to blowtorch applications.
A significant difference between the two is in the composition of the filler metal used.
- In welding, a similar filler metal to the metals being welded is used—for example, steel filler rod when welding steel.
- In brazing or soldering, a dissimilar metal is used that can act as a mediator between the disparate melting points of the two metal pieces being joined.
In some cases, a cooling agent such as water can be used to temper a welding job to solidify it more quickly.
- Move the welding torch in short runs so that you can ensure you’re getting the result you want without having to adjust the fuel-oxygen mixture. This is especially important if you’re new to blowtorch welding and are still getting used to the technique.
- When cleaning up a welding site, don’t forget to grind out cracks, too. Keep in mind that any impurities that have made their way down into metal cracks will compromise the strength of the resulting weld. Meticulous cleaning is also the key to avoiding hydrogen cracking.
- Have all your materials gathered ahead of time so that you don’t end up having to scramble for supplies in the middle of a welding session. Remember that welding is dependent on being able to work consistently and in a timely fashion since it involves bringing metal to a molten state and cooling it over and over again.
- Preheat the welding area in alloys and higher carbon metals to prevent post-weld cracking. It’s also important that the weld bead you lay down is long and wide enough to cover the crater created by the weld pool sufficiently.
- Never skimp on cleaning and preparing your base pieces of metal before you begin welding. A dirty weld is never a strong weld. Most pieces of metal come protected with an anti-corrosion coating that must be scrubbed off before welding. It’s important to remember that once this coating is removed, however, the exposed area will begin to corrode and oxidize quickly.
- It’s always a good idea to work on a project with a more experienced welder if you’ve never attempted a particular type of weld before. Metallurgy is a complicated science, and having all hands on deck can be the difference between a decent weld and a great one. Don’t underestimate the power of teamwork on a complicated welding project.
Welding with a blow can be a good entry into the world of welding since the materials are easily accessible, and the process isn’t as complicated as a technique like TIG welding.
However, it is still a highly dangerous form of metalworking that should be treated with due respect.
Can Butane Torch Melt Metal?
Can butane torch melt metal? No, a butane torch does not create enough energy or heat to melt metal, such as steel. The heat produced by a butane torch is much lower than other welding torches and can not heat metals to a melting point.
However, your butane torch may solder and braze surfaces common in plumbing and jewelry making by using a filler metal to bond the base metals or melt the finer components of gold and silver jewelry.
Almost 90% of blowtorches heat gets lost in contact with the air, which makes it inefficient.
However, you may use a butane torch for brazing and soldering standard copper pipes and tubes found in most households’ plumbing.
Why Does My Blow Torch Keep Going Out?
Why does my torch keep going out? If your propane torch keeps switching itself off, the vent holes could be filled and starving the flame of oxygen to mix with the propane.
Some propane torches have an internal regulator that allows the liquid to become vapor before it passes the flame adjustment valve and others don’t.
If you invert propane torches without a regulator too much, the liquid propane passes through the adjustment valve rather than the vapor and becomes oxygen-starved, and the flame will die.
Either that or your vent holes might be blocked, keeping the oxygen from mixing with the propane. Ensure that no debris has blocked your vent holes before attempting to use your blowtorch again.
What Is The Best Torch For Soldering Copper Pipe?
What is the best torch for soldering copper pipe? Although you may use a propane torch to solder copper, MAPP (methylacetylene-propadiene propane) is usually your best bet because it reaches greater heat intensity than traditional propane torches.
Because MAPP burns hotter so your job may get done much quicker of your copper pipe. MAPP can reach soldering heat in 5-10 seconds when soldering ½ to 3/4-inch pipes.
Because propane is slower that MAPP, it is sometimes a better option for novice welders when working on ¾’’ ½’’ copper pipe because overheating your metal is less likely. Watch out for your flux turning black for signs of overheating.
Are Blow Torches Safe?
Blowtorches may be potentially hazardous. Its elementary logic that compressed gas and a flame source can be potentially lethal if not handled cautiously.
Beyond the ignition possibilities, welders must consider factors such as fumes, ventilation, and possible eye damage from the flames.
Burns to the body are also a potential hazard, and gloves, an apron and goggles, and full-face masks.
Gas leaks must be prevented and checked for at all times, and flashbacks can be extremely dangerous.
Flashback happens when a flame retreats into the torch due to pressure inconsistencies or clogs. Welders should shut both gas cylinders down immediately.
Gas tanks must be stored safely and always be kept away from flame and heat. Non-operational tanks must never be stored alongside operational tanks to ensure safety.
Can A Butane Torch Melt Gold?
Can a butane torch melt gold? Yes, you can melt gold with a butane torch. Although it is technically possible to melt gold with a butane torch, it is not ideal as a melting device.
Gold melts at above 1,974℉ (1,064℃), and it seems logical that butane, reaching 1,430 °C (2,610 °F) would be ample heat to melt gold.
However, these are theoretical figures, and one would struggle to reach these temperatures without proper insulation. You would need to ensure your BTUs and use an insulating furnace.
A propane torch with higher average temperatures would be a better option.
Blowtorches are Primarily Designed for Cutting Metal, not Welding
Blowtorches were designed for cutting metal, rather than binding it together. Blowtorches can still be used in some braze welding and soldering applications.
Still, even though it might be possible to pull off, it is an inefficient choice for more exotic metals such as aluminum.
Despite that, blowtorches have and continue to be used effectively in many different welding applications.
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Torch Welding Can Be Done
Have you ever wondered when torch welding can be done? While a blowtorch isn’t the appropriate tool for all welding jobs, those welders who are used to higher-powered welding tools such as TIG units might be surprised at the kind of metal fabrication projects that can be accomplished with a simple propane blowtorch.
Even though lower-temperature blowtorches are better suited for brazing and soldering than actual welding, blowtorches that run on hotter fuel-air mixtures such as oxyacetylene can hold their own against more complicated welding techniques.
Regardless of which welding technique is used, however, the main factor that determines the success of the resulting weld is understanding the chemical properties of the materials at hand.
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Frequently Asked Questions
Here are a few common questions people often have about blowtorch:
Can You Solder With a Blowtorch?
Yes, you can solder with a blowtorch. A propane torch is suitable for most small soldering jobs. For large metal parts, you must use a high-heat torch. The right burner plays a big role when it comes to soldering metals.
Is Brazing As Strong As Welding?
Brazing is not as strong as welding. When it comes to welding, the temperature is higher.
The big difference between welding and brazing is that the temperature (from brazing) is lower and the base metals do not melt.
How Hot Is a Brazing Torch?
Copper metals melt at 1981°F and to avoid melting of the base material, the required temperature for the brazing torch flame should be between 1100 and 1500°F.
Is A Propane Torch Hot Enough To Braze?
It is easier to achieve a weld with a propane torch than a butane one, but propane is only suitable for brazing particular metals such as silver solder and to braze brass.
A propane torch simply cannot produce sufficient heat to perform fusion welding successfully.
Can Propane Torches Explode?
Can propane torches explode? Yes, a propane torch may explode, and they have done so in the past and claimed lives as a consequence. However, it is not an incident that occurs easily or due to superficial errors.
This most commonly occurs if the tank itself is subjected to the extreme heat that causes the tank’s pressure to exceed its safety relief valve capacity. But this would require continuous flame proximity over some time.
Always keep stored propane tanks away from propane tanks in use and away from heat sources and open flame sources. Store your propane gas torch out of direct sunlight.
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