How to Join Steel Pipes Without Welding?

Joining two steel pipes is something that is primarily done through welding. But is that the only possibility? What if your welder breaks? Or you have an emergency where you don’t have access to a welder? Can you go for alternatives?

The answer is a huge YES! Joining two pieces of steel or any other metal is possible without welding. There are several methods with which it can be done. But first, you need to understand the pros and cons of each technique to decide which to employ.

How to Join Steel Pipes Without Welding

Care to venture? Then do read more…

Is welding stainless steel difficult?

Welding stainless steel can be a tough task due to its properties. The alloy is quite transparent in showing the changes in its texture as it tends to easily distort or warp when heat is applied.

Slight marks or scratches can be easily identified on its surface. As welding requires the metal to be hot (excessively hot at times), stainless steel can give you a hard time.

Why should I go for methods other than welding to join two steel pipes?

Apart from inaccessibility to a welder and the alloy’s sensitive nature, there are certain other factors that make welding unfavorable. They are:

1.) Costlier than its alternatives: Supervision and inspection of joints welded are costlier than with other alternatives. As the latter consists of less sophisticated methods, upkeep efforts can be limited.

2.) No guarantee of strength: If you are not comfortable with welding or are not sure about the number of constituents to be used, the result cannot be up to your expectation. For instance, the wrong proportion of filler metal can result in brittle joints.

3.) Uneven distribution of heat: Temperature during welding can be quite unstable and vary and this can result in immense stress on the joints. 

4.) Tend to develop fissures: As the welded joints are not able to be moved, contracted, or expanded, racks can appear on them as time passes by.

What are the methods to join steel pipes other than welding?

There are several ways in which you can accomplish this. I am going to list the most used methods of all for you here:

1.) Brazing

Brazing is the next most effective method after welding to join two pieces of steel. Like welding, brazing also involves heat, torch, flux, and filler metal. The difference is the intensity of heat and the less sophistication involved with the process.

With brazing, the filler metal is placed above the base metal (with flux on it) and heat is applied using a torch. Unlike welding, the melting point of heat applied will be lesser than that of the base metal.

The filler metal upon getting heated, melts and through capillary action takes almost the form of an adhesive and brazes the joints.

Three points to be kept in mind while brazing is:

1. Distance of the torch: Keep an adequate distance between the torch and the base metal.  This ensures that the heat applied will not me too much for the base metal.

2. Size of the cone: Cone is the mouth of the torch. Through practice decide the size of the cone and regulate the flame for the kind of joint you are rooting for.

3. The angle of the cone: Just like in welding, the angle of the cone matters. If you are not aware of the right angle, the effect of the heat will be affected.

Pros and cons of Brazing are:

Pros Cons
Creates strong joints

Versatile technique that can be used for various applications.

Can be performed at lower temperature than welding and give almost similar results.

Joints not as strong as welding

Not suitable for larger assemblies

Not suitable for spot joints

Requires oxyacetylene torch particularly for steel.

For a quick understanding of the technique, do check this video:

How To Braze - Tips and Tricks with Paul Brodie

2.) Soldering

In terms of effectiveness, soldering comes after brazing. The components in soldering include a soldering iron, a very thin filler metal, flux, and base metal. Similar to brazing, flux is applied to the base metal.

Flux is necessary to keep the surface clean from contaminants, oxidants, or other particles. With the help of electricity, soldering iron gets heated. When the tip of the iron touches the filler metal, it melts within seconds, creating the needed content to join the pieces.

The temperature for soldering is below the one required for brazing. Often it does not go beyond 800 to 840 Fahrenheit. Filler metal will usually be an alloy, a mixture of gold, aluminum, copper, nickel, or cobalt.

Do check this link to get a strong grasp on soldering:

Brazing pdf

Pros and cons of Soldering are:

Pros Cons
Much safer and less complicated than welding

Works on mere electric connection

Heat intensity is less

Can be easily done

Results can be reversed if needed

Does not need much expertise and can be learned within few hours

Joints are not strong as welding

Does not create a mechanical bond between the pieces

3.) Riveting

Another alternative to welding steel pipes together is riveting them. Unlike the techniques we have discussed so far, this method does not involve gas or intense heat.

The process is pretty simple, where a rivet is placed inside a pre-drilled hole common to two pieces of metal, and its tail is flattened by pounding on it.

The rivet thus compressed tightens its hold joining the two pieces of metal or alloy in this case. Compared to welding, this technique involves much fewer constituents. 

Pros and cons of riveting are:

Pros Cons
Heat is not necessary (at times rivets are heated)

Useful for shear loads

Less sophisticated than welding

Takes less time to be completed

No issue of fumes or other gas-related problems

Relatively safer than welding

Suitable for various positions

Inspection of riveted joints is less expensive than welding

Better suitable for steel sheets than pipes

Joints are not gap-free

Joints are easily prone to corrosion

Modifying the joined elements is difficult compared to welding

Less integrity of joints  

See also: Is Welding Better Than Riveting? 

Check this link to see how riveting is done:

How to use a rivet gun for joining metal

4.) Adhesive

Adhesive is nothing but the glue that is used to join metals. Evaporation of the solvent involved makes the glue do its job. When applied with adequate heat and pressure these can create satisfactory strong joints.

Over the years, many experiments have been done on them that these solvents are used widely today in industries such as automobiles, aerospace, structural and more.

There are different types of adhesives such as epoxy, silicone-based, and polyurethane. Double-sided tapes are also used in some cases. 

By the entry of plastic-based adhesives, these are increasingly used as an alternative to join metals especially steel.

Epoxy in particular is highly recommended due to its special composition involving nanoparticles that are powerful enough to create pretty strong joints, unlike the traditional adhesives. 

Pros and cons of Adhesives:

Pros Cons
Easiest method

Cheap alternative

No risk involved

Reduced stress concentration on joints 

Free of issues such as corrosion. discolouration  or distortion

Not much post-clean up needed

Weaker joints

Not suitable for heavy pieces of steel

Joints can lose integrity in high temperatures

Difficult to disassemble the joints

Surface preparation is necessary

See this video to see how adhesive can be used to join two steel rods:

Stainless Steel Adhesive

5.) Nuts and bolts

Using nuts and bolts is very similar to riveting. Like the latter, there will be two pieces to join with pre-drilled holes, but instead of a rivet, nuts and bolts are used in this case.

If the base is threaded, then only bolts are used. Nuts and bolts can be inserted and placed tightly using a drill thereby firmly joining the two steel pipes.

Pros and cons of using nuts and bolts are:

Pros Cons
No heat required

Only two elements needed ( Nuts/bolts and a wrench)

Less riskier than welding

Not leak proof

Not as strong as welding

Better suitable for sheets than pipes

Can spot welding two steel pipes be an alternative to welding them?

Spot welding cannot be considered as an alternate method to welding as it is a type of welding itself. It is called ‘resistance welding’. It is one of the earliest welding methods out there. This technique is suitable for thin metals like stainless steel.

Mostly used in automobile industries, spot welding is preferred for sheets more than pipes. While normal welding uses arc to create sparks to melt the base metal, here electric resistance is used to achieve the same goal. Hence, spot welding cannot be added to the list that I mentioned above.

To conclude

Even though there are many alternative methods to welding that have been there for years and many are being developed using the latest technology, the preference is given to welding never subsides.

But in certain conditions like the ones that I have mentioned initially in the blog, other methods are used to join steel pipes or any other metal for that matter.

Hope you had fun reading this blog post!

Do come back for more!

Steve Goodman
Experienced welder with 7+ years of expertise in all the latest welding techniques MIG, flux and stick welding, drill press, crane operation and metal fabrication. Welding certificate course graduate and 2018 Excellence in Welding award winner.

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