How to Use a Blowtorch

Co-authored by Surekha Krishnan

Last Updated: August 26, 2024

Blowtorches can seem intimidating, but they are very handy tools if you know how to use them correctly. From cooking to soldering pipes, you can use a blowtorch in many household and DIY projects. The most important thing to remember is to practice safe technique and use the right blowtorch for your purpose.

Method 1

Method 1 of 5:

Setting up and Storing a Blowtorch Safely

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1
Fill handheld propane or butane torches with disposable fuel canisters. A handheld torch will have a refill port at the bottom. Flip the torch upside down and insert the nozzle of the gas canister into the port. Press and hold the canister directly on top of the torch for a few seconds before removing it from the port. It only takes a short time to refill a handheld torch, so be sure to remove the gas canister before any gas leaks out.
- You may hear a hissing sound as you insert the nozzle, but should not hear gas escaping once you have removed the canister.
- Always use the appropriate gas for your type of blowtorch. Using the wrong gas can cause an explosion!
2
Connect the gas and oxygen canisters if necessary. Propane, MAPP gas and acetylene are often used with oxygen tanks to help the gas burn at a higher temperature and concentrate the flame. Attach a regulator, flashback arrestor, and hose to each tank (in that order) by hand-screwing the connections and then tightening them with a wrench. Make sure the connections are tight and there is no damage or cross-threading, as this may allow flammable gas to escape. Finally, attach your nozzle and ignition to the end of the hose. ^{[1]
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- If you have both a gas and an oxygen cylinder, use the corresponding tubing and regulator for each, and never mix and match!
- Check the cylinders for gas leaks and damage before you set up your system. If the cylinder seems damaged or you smell gas, call your dealer for immediate pickup.
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3
Turn on your blowtorch by opening the gas valve and lighting the nozzle. Open the valve on your gas cylinder just enough to release a small but steady flow of gas. Facing the torch away from your body, click the igniter or light the gas with a sparker. The flame should turn on and blow at a constant rate without sputtering. ^{[2]
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- Keep your torch fully upright while it’s burning!
- Don’t turn your gas valve more than a quarter turn to light the torch, as you can release too much gas in the air and create a fire plume.
4

Use the valve to adjust the flame a gap between the flame and the tip. You can create different flame sizes by turning the torch valve. Opening or turning the valve counterclockwise will create a larger flame, while closing or turning the valve clockwise will give you a small flame. No matter the size of your flame, make sure that it looks like it’s still touching the tip of the torch, otherwise, the torch is emitting too much gas. ^{[3]
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5
Turn off the torch by closing the gas valve completely. When you want to turn off your torch, close it at the source of the fuel first (the valve of the gas tank). Once the gas valve is completely closed, your torch flame will reduce. Open the valve all the way on the torch to burn off any remaining gas in the tube system. Once the flame is out, the torch will then be safe to dismantle. ^{[4]
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- Don’t forget that the torch tip will still be extremely hot even after the flame has gone out!
- Dismantle your torch immediately after you have finished using it.
6
Dismantle and store your torch equipment in a cool, well-ventilated area. After the torch has been turned off at the source, open the two valves on the gas regulator and disconnect the regulator from the cylinder. Replace the cylinder cap tightly. Unscrew all other connections on the torch system. Store your cylinder upright in a cool, protected space with good ventilation.
- Store gas cylinders away from anything combustible.
- Keep oxygen and gas cylinders separated, and separate full cylinders from empty ones.

Method 2

Method 2 of 5:

Using a Blowtorch for DIY Projects

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1
Choose a butane torch for smaller indoor projects requiring low heat. Butane torches are the smallest type of blowtorch and are also known as micro torches or crème brûlée torches. Micro torches can be set up easily as they simply require the torch and a compatible fuel canister to fill it. Butane does not burn at temperatures hot enough for metal-cutting, hard soldering, or welding. ^{[5]
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- You can add a pencil tip for precision when soldering small items.
- Because of its low toxicity, a butane torch can be used and stored safely indoors with proper ventilation.
2
Opt for propane for soldering pipes and general DIY projects. Propane is the most common fuel for household blowtorches, as it is versatile and burns hotter than butane. Typically, a handheld propane blowtorch is the right tool for soldering copper pipes and removing or adding sealant, as well as various other DIY projects. Propane is also cheap and can be purchased in tanks. ^{[6]
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- You can use a propane and oxygen setup to create a very hot flame.
- Propane torches can also come in handheld varieties.
3
Use MAPP gas or acetylene for projects that require high temperatures. MAPP gas, or the combination of liquefied petroleum and methylacetylene-propadine, is the gas to use when you need a hot but precise flame, as it burns at a higher temperature than propane and butane. Acetylene can also be used for high-temperature projects such as cutting and welding but is less popular due to its explosive nature and dirty emissions.
- You may need a certification to use MAPP gas due to its high temperature.
- Acetylene is used with a gas tank and a separate oxygen tank. ^{[7]
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4
Cut metal with a high-heat MAPP gas blowtorch. Cutting metal with a blowtorch requires very high heat and is best done outdoors or in a workshop with good ventilation. To reach the correct temperature, you will need to use MAPP gas. Use a welding mask and beware of liquid metal, which can splatter and burn your skin. Move the torch flame steadily across the metal, and it should cut easily and quickly under the right heat. ^{[8]
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- A tank system with acetylene and oxygen can be more combustible, so take the necessary safety precautions!
5
Strip paint with a propane blowtorch. You can use heat to strip paint by melting it off a surface. Hold the flame over the paint until it starts to bubble and melt, then scrape it off the surface with a paint scraper. Be sure to keep the flame far enough that it doesn’t scorch and discolor the material underneath. This is especially important with wood. ^{[9]
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- If the paint is thirty years or older, don’t use a blowtorch to remove it! It may contain lead and will create toxic fumes when burned.
6
Light charcoal and wood chip grills with a propane blowtorch. A blowtorch is one of the easiest ways to light a charcoal or wood chip grill, especially if you don’t want to inhale fumes from a liquid lighter. Once you’ve filled your grill with charcoal, concentrate the torch flame on two or three areas for a few minutes each. Let them burn for a few minutes after you remove the flame, and then close the lid to help even the temperature throughout the grill. ^{[10]
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- Always light your torch pointed away from the grill, then adjust the flame before using it.
7
Remove weeds with a propane blowtorch. There are specialized propane torches that are mobile and can be used while standing for this exact purpose. Weed-killing with a blowtorch is effective, especially if you aren’t interested in using poison. Make sure your weeds aren’t near other flammable brush or other material (including your home) that can catch fire easily. ^{[11]
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- Be careful when using a blowtorch on dry weeds or grass as they can easily catch fire.
- You can rent these specialized blowtorches, but you may need to be certified to operate one.
8

Repair driveway cracks evenly with a propane or butane blowtorch. Driveway cracks don’t have to be permanent and are easy to fill using a blowtorch! Clean the crack by removing any buildup, weeds (use a blowtorch to remove these, too!), or other material that could loosen your joint filler. Use a joint filler that is designed to be heated with a torch, and apply it liberally into the crack. Heat the filler with the torch at a low heat setting, sweeping evenly over the crack until the filler solidifies. ^{[12]
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Method 3

Method 3 of 5:

Cooking with a Blowtorch

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1
Use a butane or propane torch designed for the kitchen. Cooking with a blowtorch has become popular, and there are many blowtorches available that are designed for kitchen use. Most of them are handheld and use butane because it burns cleanly, so you will be less likely to emit gases onto your food. In fact, butane micro torches are also known as crème brûlée torches. ^{[13]
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- There are many hand-held torches that are lightweight and easy to use.
2
Ventilate the area and keep a fire extinguisher handy. Even though kitchen torches are small and can be used indoors, they still require safe practices. Open windows to create a ventilated area and remove anything flammable from your station. Use a cast iron skillet or metal tray placed on the stovetop and keep your fire extinguisher nearby in case of fire. ^{[14]
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- Don’t use a cutting board. The wood or plastic materials can melt or catch on fire!
3
Turn on the blowtorch facing away from the food and adjust the flame. Aiming a blowtorch at anything before you ignite it can be dangerous, and lighting a blowtorch onto food is a recipe for disaster. Torched food can develop a “torch taste” of unpleasant fuel if the fuel leaks without burning. You can avoid this by turning the fuel on until you hear a hissing sound, lighting the ignition, and adjusting the flame until it is blue. ^{[15]
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- Make sure the torch nozzle is clear of any food particles before you ignite it as this can damage your torch and is a fire hazard.
4
Use a sweeping motion to scorch the food. Slowly and carefully sweep the blue flame across the food without holding it in place for too long. The important thing to remember is that the torch alone may not cook your food all the way, and lingering over one area for too long can burn it. Some recipes, such as torching steak, will require a slower sweep. Others, such as toasting marshmallows, require very brief contact with the heat. ^{[16]
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- Do not torch the food in circular motions as this will cause the food to cook unevenly. Use broad strokes over the entire surface.
- You may not need to use the sweeping motion if you are blistering vegetables or removing pepper skins.
5
Follow a recipe for optimal results. If you are new to cooking with a blowtorch, you may not know all the ways that it can be used in the kitchen, and there are many! Blister vegetables, caramelize the top of crème brûlée , sear fish and other meats, crust macaroni and cheese, skin peppers, and more. It’s always a good idea to have a recipe for blowtorch cooking, as each dish requires different techniques. ^{[17]
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- If you’re using a cookbook, keep the book nearby and open on the page with the recipe for easy reference.
- If you’re referencing a recipe on your phone, be sure to follow safety precautions while your eyes are away from your torch!

Method 4

Method 4 of 5:

Soldering Metal with a Blowtorch

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1
Use propane for small jobs and a high-heat torch for large metal pieces. When it comes to soldering metals, the right torch makes a big difference. A propane torch is suitable for most soft-solder jobs where the solder “sweats” or liquifies and connects the metals. You will need a MAPP gas torch or oxy-acetylene torch system to hard solder metals and for larger soldering projects. ^{[18]
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- Hard soldering is similar to welding, as the metal pieces melt and are fused to the solder. Soft solder melts to join metals, but the metals themselves do not melt.
- Some MAPP gas torches may require certification for you to use them, and there are laws that will restrict you from using and storing oxy-acetylene torches in apartments.
2
Set up a torch in a clear space and use firebrick for high-heat projects. Propane and MAPP gas torches should be used outside. Firebrick is a special type of brick that is treated to stand the heat of a blowtorch. Clear the area of anything flammable and keep a fire extinguisher and bucket of water within reach. ^{[19]
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- Metals, woods, and even regular bricks can be hazardous when heated.
- You should also clear the area of any obstructions that may get in the way. This could be furniture, equipment, and even pets!
- If you need to work indoors, open all windows for good ventilation.
3
Wear goggles, gloves, and non-flammable clothing. Keep yourself safe by protecting your eyes, hands, and skin from the heat of the blowtorch, as well as any flux that might melt in the process. Tie your hair back, as hair is highly flammable. When using a high-heat torch, it is always good to wear protective goggles. ^{[20]
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- Do not wear any loose-fitting clothing or clothes that may impede your movement.
4
Prepare metal fittings by smoothing them and cleaning off any residue. Every piece of metal that you are soldering needs to have a clean, smooth surface so that the solder will stick and the bond will hold. Scrub the surfaces of your metal pieces with a wire brush or sandpaper. ^{[21]
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- You can use commercial pipe cleaners if your fittings have a large amount of buildup.
5

Apply a small amount of flux and fit your metal pieces together. Flux is a paste that helps the solder create a stronger, better fitting bond. Apply it to your metal pieces using a flux brush, making sure not to get any on your hands or work surface. Fit your metal pieces together in the way you want to solder them. Wipe away any excess flux with a cloth. ^{[22]
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6
Ignite the torch and heat the fitting until the flux bubbles. Light the torch and adjust it until you see a consistent blue flame. Heat the metals where you want to solder them together, and remember that it can take some time for metals to be fully heated. You’ll know when the metal pieces are ready to solder when the flux begins to bubble and steam through. ^{[23]
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- Always ignite your torch while it is aimed away from you or anything flammable!
- Even though you are heating the area to be soldered, the rest of the metal can get very hot, so be careful!
7
Apply solder to the joint until it covers it completely. Gently apply solder to the joint, moving from the top to the bottom of the joint. The solder will be pulled quickly into the joint, and you can use gravity to help you coat the entire joint by beginning at the top and working down both sides. ^{[24]
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- Make sure to solder all joints at once, as reheating the metal can damage the existing solder.
- Have your solder ready to go so you don’t have to stop and risk the metal cooling down before you are finished.
8
Wipe away excess solder and let the metal cool before moving it. Excess solder can be rough and difficult to remove once it’s dried. Using a damp cloth, wipe away solder carefully (it’s hot). The solder can dry before the rest of the metal pieces cool down, so wait to move your work until everything has cooled. ^{[25]
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- Don’t worry if you still have excess solder on your project once it dries. You can use a metal file or sandpaper to smooth it after your project has cooled.

Method 5

Method 5 of 5:

Making Jewelry with a Blowtorch

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1

Choose a butane micro torch with a pencil tip. Due to its small scale, making jewelry requires a great amount of accuracy, and a pencil-tipped butane torch is the best blowtorch for basic jewelry-making. Micro torches are precise, easy to hold and maneuver, and can be used indoors because of their low emissions. With a handheld butane micro torch, you can soft-solder, torch-fire clay and enamel, close jump rings, and bend wire. ^{[26]
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2
Use a MAPP gas or acetylene torch for silver soldering and fusing. Silver soldering is also known as hard soldering or brazing when it applies to jewelry. The solder melts at a much higher temperature than soft solder, and the bond that is formed is stronger. Fusing is a term for welding jewelry by melting and joining the actual metal pieces, sometimes with a solder made of the same metal. Both of these processes require high-heat torches.
- Silver, gold, brass, and bronze can all be joined with a hard solder.
- You may need to have specific certifications to use MAPP gas torches, so check to be sure you can use one.
- Hard soldering and fusing require some expertise.
- When using a high-heat torch such as MAPP gas or acetylene, take extra precautions to protect your body from the flame or molten metal drops!
3
Use soldering blocks to create a work surface and clear the area. Remember, jewelry is made up of different metals, fabrics, and materials, and some of these can be highly flammable! Only solder metal, non-flammable jewelry and use a soldering block to work on. Soldering blocks are specially made to stand the heat of a torch and can be made of firebrick, porcelain, pumice or charcoal.
- You can order soldering blocks online or find them at hardware stores.
- If you are working indoors, open all windows to make sure your area is well ventilated.
- Keep your fire extinguisher in an easy-access place in case anything burns.
4
Prepare jewelry surfaces by removing grease, buildup, and rough edges. The surfaces that you are soldering must be oil-free and flush at the joint when you put them together for soldering. Clean off any buildup by rinsing the jewelry pieces with soap and water, and then use 1000 grit sandpaper to lightly smooth the surfaces that will be joined. Some harder metals may require a metal file. ^{[27]
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- After using soap and water, make sure you rinse the pieces with clean water.
- Be very gentle when you smooth your jewelry surfaces, as the pieces are small and may scratch or break.
5
Apply flux to coat the jewelry pieces and align them into position. Flux is a paste that you apply before solder to guide it and help form a stronger bond between the two pieces. It will also protect the jewelry pieces from being scorched by the flame, an effect called firescale. Use a flux designed for jewelry, as it will contain different chemicals than an electrical flux. Make sure your jewelry pieces are flush against each other so that the solder can flow into the seam. ^{[28]
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- Firescale is an undesirable oxidation effect that can appear on metal when it’s scorched, and a thicker coating of flux can help to prevent it.
6
Ignite your torch and heat the metal until the flux becomes translucent. Always aim the torch away from anything flammable when igniting. Adjust your flame to the desired temperature and heat the jewelry pieces, beginning with the largest. When the flux is translucent and begins to bubble, you are ready to apply solder. ^{[29]
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- The most effective flame for soldering jewelry is a neutral flame, meaning you should not be able to hear the gas burning.
7
Remove the flame and apply solder to the seam. Touch the solder to the seam to see if it will liquify. When the jewelry pieces are hot enough, the solder will be able to flow into the seam quickly. Remove your torch once the solder begins to flow to avoid overheating the metals and causing dark oxidation, commonly known as firescale. ^{[30]
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- Make sure the torch is off and the flame is completely extinguished!
8
Dip the jewelry into water to cool before adding it to a pickle solution. A pickle bath is a highly acidic solution used to clean jewelry and remove oxidation caused by the flame. You can make your own with vinegar or purchase a stronger chemical solution. The jewelry will be very hot after soldering, so cool it in water before dipping it to the pickling solution to prevent hot acid splashing.
- Use plastic tweezers to hold the jewelry while you dip it into the solution, as metal tweezers can affect the chemicals.
- After soaking the jewelry in the pickle for a few minutes, remove it and rinse the pickle off with cool water, being careful not to let the pickle touch your hands.

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Warnings

Blow torches can be very dangerous. Be sure that you are taking all safety precautions and you have a fire extinguisher nearby.

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