How to cut galvanized pipe?

What are galvanized pipes and where are they used?

Galvanized pipes are specially treated steel pipes commonly used in applications that often include contact with highly volatile and reactive materials and elements.

Galvanization is the process of dipping regular steel pipes in a batch of molten zinc to give them an extremely long-lasting and protective layer of corrosion resistance. 

Given their enhanced properties, galvanized steel pipes are more expensive, but are also the only near-fail-proof options for industries that involve highly corrosive agents such as those in chemical processing, maritime applications, fire control systems, and sewage control.

What is the best way to cut galvanized pipe and what do you need to consider when doing so? Let’s find out below.

Considerations when cutting galvanized pipes?

• Tool availability. Because of the added zinc coating, while the same conventional tools can be used to cut galvanized pipes, some may prove more efficient than others. Ideally, to avoid damaging much of the zinc layer, it’s preferable to use power tools or several saw types with the right blade for a fast cut.
• Blade type. It’s important to note that using a dedicated fine-toothed steel-cutting blade will offer the best results. Though some woodworking HCS blades will do for thinner pipes, HSS blades are generally better overall.
• Threading requirements. Galvanized pipes can be threaded to fit into threaded pipe fittings also made of galvanized steel. When threading, it’s important to use a die head that corresponds with the pipe’s diameter. Apply ample threading lubrication to make threading easier.
• Size. Of course, longer and larger pipes are harder to cut. The more material to cut, the more technical and specialized the process becomes, often needing more capable tools such as a 9-inch angle grinder or heavy-duty steel pipe cutters.
• Space. Limitations in space can interfere with smooth cutting. If it can’t be helped, use a reciprocating saw or an angle grinder to cut galvanized pipes in tight spaces.

Using a pipe cutting tool

Here are the materials needed: A galvanized pipe cutting tool, vise/clamp(optional), pipe, marker. 

Procedure

1. Take stock of the pipe/s you want to cut to identify the most effective type of pipe cutter to use (since there are different ones). 
2. Place the pipe in the cutter’s jaws. If you’re using an adjustable pipe cutter, tighten the jaws around the pipe until it’s fully wedged between the roller and the cutting wheel.
3. You can now start cutting at this point. For adjustable cutters, you may want to first do a test groove to see if you’ll cut straight. If you’re happy with the fit, simply rotate the cutter until it eats through the pipe.
4. Pipe cutters pretty much work like scissors. Mark where you want to make your cut and squeeze repeatedly on the handles until you make it through.

Using a reciprocating saw

To cut the galvanized pipe with Sawzall, here are the materials needed: Reciprocating saw (Sawzall), vise/clamp, pipe, marker

Procedure

1. Identify and mark where you’ll be cutting. Clamp the piece down after.
2. Set your saw’s orbital action. Remember to use a steel-cutting blade for optimum results.
3. Set the speed setting corresponding to the size of the workpiece.
4. Set the saw against the mark and slowly work your way through. If you feel that there’s a bit of snagging, increase the speed.

Use a chop saw

Materials needed: Chop saw, pipe, marker, square rule

Procedure

1. Set up the saw and make sure to use the correct type of blade.
2. Place something flat and solid underneath the saw for additional stability. Set the packers a little bit low.
3. Use the square to check that the face of the disk is square off the pipe. 
4. Mark the workpiece and line it up under the disk. Be prepared for a little sight-offset since visibility can be challenging, especially if the marks are hard to see.
5. Lower the disk until you fully cut through the galvanized pipe.

Using an angle grinder

Materials needed: Angle grinder, a workbench or vise/clamp, pipe, marker, or chalk

Procedure

1. Arm the grinder with a metal-cutting or diamond disk. 
2. Mark where you’ll be cutting. 
3. Secure the workpiece in place using vises or clamps, or on a workbench, if you have one. 
4. You can make an initial groove to make subsequent passes easier and for a cleaner finish. 
5. Follow the perimeter sections of the pipework until you finish your cut. Pipes with a diameter of more than 5-inches will definitely require multiple passes.

Using a hacksaw

Here are the materials needed when cutting galvanized pipe with a hacksaw: Hacksaw, vise/clamp, pipe, marker

Procedure

1. Make sure to use a wavy, fine-toothed blade.
2. Identify and mark where you’ll be cutting and clamp the piece down.
3. Line the saw up with the mark and begin cutting. Proceed with slow, steady strokes for cleaner results. You can use this moment to also start with an initial groove cut to make cutting easier later on. 
4. Make sure to have some sort of basin that catches cut pieces, especially if you’re working far from the ground.

How to cut galvanized pipe or railing?

Galvanized pipe is just as viable as material for chain-link fencing, if not better, than regular steel piping. Galvanized pipes provide superior railing options and function as sturdier longer-lasting support sections because of the added zinc layer.

It’s actually better to cut these at ground level instead of digging out the concrete holding them in place.

Procedure

1. Measure and mark your desired length on the fence posts. 
2. Clamp them down on a workbench or any flat area with a heavy-duty vise with marks 4 – 6 inches from the vise’s end. 
3. You can use a hacksaw for relatively smaller workpieces, but the reinforced structure of galvanized pipes makes power saws like an angle grinder the more viable option.
4. File and smoothen out jagged edges after the cut. You can thread edges for custom fences that connect via fittings.

How to cut galvanized pipe under kitchen or bathroom sink?

The main thing that separates cutting galvanized plumbing pipes and tubings from cutting standard pieces of galvanized pipe is the fact that most of them are curved and confine you to working in extremely tight spaces.

Procedure

1. Disconnect and drain any services.
2. Identify and measure the piece of piping that needs work. 
3. Clamp down the piece in place or cut as is if you’re comfortable working under the sink. It’s advisable to use a pipe cutting tool or angle grinder since the shape of the pipe makes it a bit harder to cut.
4. With your chosen tool, make a completely perpendicular cut.
5. Polish/debur and thread as needed.

How to cut a hole or circle in a galvanized pipe?

It’s better to simply use a drill for holes and circular cuts in piping rather than to manually cut them out using other tools. The pipe’s cylindrical shape will make cutting out circles and holes even more difficult.

A quick and easy solution to this is to just use properly sized metal HCSO or HSS drill bits. Besides exerting less stress on the workpiece, drilling also provides more symmetrical holes with greater geometry. 

Tips for cutting galvanized pipes in tight spaces

• Make sure to always wear the proper protective equipment. Prioritize shielding your face and hands.
• Ensure that your work area is properly lit. Use highly visible markers.
• Make sure you have a ready set of clamps and pipe pliers.
• Always use metal-cutting blades.
• Always double-check services are disconnected, and there is no nearby gas. 
• Focus on cutting galvanized pipe with a reciprocating saw or angle grinder as they offer better reach than other tools for this specific task.  
• Get rid of any flammable substance before starting (cutting will generate sparks that might combust).
• Always debur cuts for a clean and safe finish.

Safety precautions when cutting galvanized pipe

• Make sure to at least wear a mask since galvanized steel is said to release toxic zinc fumes when cut. Inhalation of too much of these fumes can lead to a very debilitating condition known as ‘Metal Fume Fever’.
• Cutting galvanized steel can potentially cause explosions due to a chemical reaction from the sparks generated and the hydrogen gas produced from the zinc.
• Best wear gloves that cover up to the forearm. In addition to large amounts of small metallic shavings, zinc chloride dust also flakes off when cutting galvanized steel and can potentially irritate the skin on contact.  

Conclusion

Galvanized pipes are basically better, and more expensive, versions of regular steel pipes. They’re more durable and look better. Their longer lifespans also add to their versatility, making them essential in applications with highly corrosive elements.

Cutting galvanized pipes is a bit riskier given the various reactions the zinc layer can cause but is also good since it can help save on costs in the long run. Fortunately, cutting these doesn’t differ much from cutting regular metal pipes, so having at least knowledge on that makes everything “zinc in” a little easier.

And lastly, if you cut galvanized pipe the cut will not have the protective galvanized layer so you will need to manually apply zinc from a  spray can to protect the cut edges from rusting.