How to Make a Very Durable (and Cheap) Welding Slag Hammer

Introduction: How to Make a Very Durable (and Cheap) Welding Slag Hammer

About: I like to do electronics, metalworking, woodworking, fixing things and all sort of cool and stupid things :) I also have a YouTube channel:

I bought my first welder some 12 years ago. A simple transformer based stick (arc) welder.

I wanted to learn to weld with it and I needed a simple first project. And I found it. A slag hammer - the most basic arc welder necessity.

I made it by welding a regular nail to a construction iron rod. It somewhat worked.

The only problem was that the nail is made from a soft metal and it needed to be resharpened constantly since it went blunt very fast.

Fast forward 12 years.

Recently I had a bigger welding job to do and I decided to upgrade my slag hammer a bit.

I was searching for a more durable tip what would not need to be constantly resharpened.(because I don't make the nicest welds and I need to hit the slag quite a lot :)

And I found the perfect (and cheap) material - a SDS hammer chisel.

Here is the video of the build and in this instructable I will further explain some details.

Step 1: What Is Slag?

Slag is what remains from a welding flux. Its mission is to protect the weld from oxidation in arc (stick) welding.

Other welding methods use inert gas (CO2 or Argon) for shielding the weld. These methods produce nicer welds, but the machinery is more expensive.

The slag i

After weld is cooled down, the slag needs to be chipped away as it is not needed any more.

And here comes the SLAG HAMMER!

Step 2: Commercial Slag Hammers

I found them to be too expensive for my taste(and for what they are), so I decided to build my own and learn something during the process.

Step 3: The SDS Bit

The SDS bit was developed by Hilti and Bosch in 1975. The name comes from the German "Stecken – Drehen – Sichern" (Insert – Twist – Secure), which enables for the bit to be inserted into the chuck without tightening.

But this is not the reason why we use this bit for our slag hammer.

These tips are made from very hard metal alloy which needs to withstand millions of impacts against a stone or concrete when used by a rotary hammer drill.

You can get these bits for almost free from a scrapyard, flea market or a local worker or a friend who has a broken SDS hammer machine.

Or you can even buy them for quite cheap.

Step 4: Cutting the Bit

These bits are made from a very hard metal and while cutting you will quickly see if you have good grinding and cutting discs or not :)

Use discs for stainless steel which are usually better quality. But still I had problems with one brand which did not want to cut the bit at all despite being rated for stainless. (see in the video).

Those discs that could cut this metal were still being worn out 10 times faster. One cut and almost 20% of the discs is gone!

But this is also a good thing, since this means that our slag hammer will be very durable and will last a long time.

And don't forget the safety glasses and hearing protection! you have only two eyes and ears!

Step 5: Welding the Bit to the Handle

For the handle I used a siple construction iron rod, which has a nice texture on it for a nicer grip.

Welding the parts together is simple as it requires to do just couple of simple welds.

Align the pieces together, connect ground terminal and FZZZZT! :D

Step 6: Shaping the Ends

Then you need to shape your tool.

On one end you want the pointy tip and on the other side you want a chisel.

I used a cutting and grinding disc on my angle grinder for this job

You will probably wear out at least half of each disc doing it since the material is so hard, but casualties need to be made for the greater cause :)

Step 7: Slag Hammer Complete!

Now just hit some slag and enjoy your creation for many many years to come!

You can follow me on Facebook and Instagram

for spoilers on what I am currently working on, behind the scenes and other extras!

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    2 years ago

    Informative video, thanks for providing this -- I also appreciate the information about the cutting/grinding discs, as well as the illustration showing what's occurring during the welding process! This Instructable & YouTube video helped me understand how simple the design can be and how small of a hammer can be used to chip off slag. Good job.


    Reply 2 years ago

    I appreciate your feedback!