Fireball Tool Mutant Square – Welding & Fabrication Square

The Fireball Tool Mutant Square combines the versatility of several Fireball square designs into one heavy-duty tool built for accurate welding fit-up, fabrication, alignment, and assembly.

With two 90° corners, a 45° reference, and a cutaway corner for weld access, the Mutant Square gives fabricators multiple ways to position and hold material while still leaving room to reach the joint.

Available in 8", 10", 12", and massive 20" sizes, with your choice of Cast Aluminum or Cast Iron + Dragon Scale, the Mutant Square can handle everything from everyday tubing and frame fabrication to large structural assemblies.

Built for Welding Fit-Up

Getting your material properly positioned before welding is one of the most important parts of fabrication.

The Mutant Square gives you a rigid reference surface for quickly aligning parts and holding them in position during setup and tack welding.

It's an excellent choice for:

• Square and rectangular tubing

• Frame fabrication

• Gates and railings

• Welding tables

• Structural fabrication

• Large fabricated assemblies

• Inside corner welding

• Tack welding and fit-up

• Production fabrication

• General metalworking

Position the square, align your material, clamp everything in place, and start welding.

90° & 45° Setup Options

The Mutant Square provides multiple angle references in one tool.

You get two 90° corners for common square fabrication work along with a 45° angle for angled fit-up and layout.

That gives the Mutant considerably more versatility when moving between different fabrication setups.

Cutaway Corner for Better Weld Access

One of the standout features of the Mutant Square is its cutaway corner.

Traditional squares can position your parts correctly but then block access to the exact joint you need to weld.

The Mutant is designed differently.

Its open corner gives your TIG torch, MIG gun, or electrode room to reach the joint while the square continues holding your parts at a true 90°.

This can be especially useful when tack welding inside corners or building assemblies where you don't want to remove the square immediately after positioning the material.

Included L-Tab Helps Keep the Joint Open

Fireball's included alignment tabs add even more flexibility to the Mutant Square.

The L-Tab can help secure and reference your workpiece while leaving the actual corner open for welding.

This lets you establish your fit-up, hold the material square, and maintain better access to the joint.

Five Edge Location Tabs Included

Each Mutant Square includes five Fireball Tool Edge Location Tabs.

The tabs provide additional reference surfaces for quickly aligning your workpiece with the square.

They can attach to the front or back, allowing you to configure the Mutant around the project instead of forcing every project into the same setup.

The tabs can also reduce your dependence on a dedicated fixture table for basic alignment work.

Four Tool-Less Thumbscrews

Fireball includes four tool-less thumbscrews for adjusting the tabs.

No Allen wrench or hex key is required.

Simply loosen the thumbscrew by hand, reposition your tab, and tighten it back down.

For fabrication setups that change throughout the day, tool-less adjustments can save time and make the square much easier to reconfigure.

C-Channel Design

The Mutant Square uses a C-channel beam with an offset web.

This design helps provide a rigid reference structure while making the square easier to position along edges and around fabricated assemblies.

Combined with the open joint access and alignment tabs, the Mutant becomes much more than a conventional square used simply to check a finished corner.

It's designed to become part of the actual fit-up process.

Choose Cast Aluminum or Cast Iron + Dragon Scale

Fireball Tool offers the Mutant Square in two material options.

Cast Aluminum

The Cast Aluminum Mutant Square is the lighter option and is particularly useful when the square needs to be moved frequently.

Advantages include:

• Lightweight construction

• Easier to move around the shop

• Well suited for mobile welding

• More resistant to warping than standard aluminum billet

• Natural light resistance to weld spatter

Aluminum is a great choice when portability and ease of handling are priorities.

Cast Iron + Dragon Scale

For heavy shop fabrication, choose Cast Iron with Fireball Tool's Dragon Scale coating.

Advantages include:

• Heavy-duty construction

• Extremely resistant to warping

• Resistant to dents and burrs

• Excellent stability during fit-up

• Dragon Scale weld-spatter protection

• Improved corrosion resistance compared with Fireball's previous black oxide finish

The additional weight also helps create a substantial, stable reference when working on a fabrication table.

Four Sizes Available

The Mutant Square is available in four sizes, allowing you to match the tool to the scale of your work.

8" Mutant Square

Dimensions: 8" × 8" × 1.5"
Flange: 1.5"

Approximate weight:

• Aluminum: 2 lb

• Cast Iron + Dragon Scale: 6.7 lb

The 8" version is compact enough for everyday fabrication while still providing plenty of reference surface for tubing and smaller frames.

Made in USA.

10" Mutant Square

Dimensions: 10" × 10" × 2"
Flange: 2"

Approximate weight:

• Aluminum: 4 lb

• Cast Iron + Dragon Scale: 12 lb

The 10" provides a nice middle ground for general shop fabrication and larger tubing.

Made in USA.

12" Mutant Square

Dimensions: 12" × 12" × 3"
Flange: 3"

Approximate Cast Iron + Dragon Scale weight:

• 18 lb

The 12" gives you considerably more reference surface for larger frames and fabrication projects.

Made in USA.

20" Mutant Square

When the project gets serious, there's the 20" Mutant.

Dimensions: 20" × 20" × 3"
Flange: 3"

Approximate weight:

• Aluminum: 27.6 lb

• Cast Iron + Dragon Scale: 71.4 lb

This is a substantial fabrication square intended for large assemblies where smaller squares simply don't provide enough reference surface.

20" version is imported.

Optional Edge Alignment Pins

Add Fireball Tool Edge Alignment Pins to expand the Mutant Square's setup capabilities even further.

Depending on your configuration, Edge Alignment Pins can help you:

• Position the square off the edge of a table

• Create vertical or perpendicular setups

• Raise the square for additional welding clearance

• Establish different alignment references

• Create parallel layouts

• Position the square around larger fabricated frames

Pairing the pins with Fireball Tool shims can also provide a convenient way to create consistent spacing when marking parallel lines.

Key Features

• Heavy-duty welding and fabrication square

• Combines features from multiple Fireball square designs

• Includes two 90° corners

• Includes a 45° reference

• Cutaway corner provides easier weld-joint access

• Helps hold material square while leaving the joint accessible

• C-channel beam with offset web

• Includes 5 Edge Location Tabs

• Tabs can attach to the front or back

• Includes 4 tool-less thumbscrews

• No Allen wrench required for tab adjustments

• Available in 8", 10", 12", and 20" sizes

• Available in Cast Aluminum

• Available in Cast Iron + Dragon Scale

• Compatible with optional Edge Alignment Pins

• Excellent for tubing, frames, gates, railings, and structural fabrication

• Designed for welding fit-up, alignment, and assembly

• 8", 10", and 12" versions are Made in USA

More Access. More Setup Options. One Serious Fabrication Square.

A welding square shouldn't just tell you whether your project is square after you've already built it.

The Fireball Tool Mutant Square is designed to become part of the fit-up itself.

Use the 90° references to align your material, take advantage of the cutaway corner to access the weld joint, reposition the included tabs as needed, and keep your assembly where you want it while you tack everything together.

From the compact 8" model to the massive 20" version, there's a Mutant Square for just about every scale of fabrication.

Set it. Clamp it. Access the joint. Weld it.