Carbon Steel Square Tubing 1.5 in x 3/16 in x 36 in - Structural

In this review of the OnlineMetals A500/A513 carbon steel square tubing, the bottom line is simple: this is a solid, no-frills choice for fabricators and hobbyists who need a dependable structural member that is ready for modification. The reviewer found the tube most valuable for builds requiring a straight, uniform 1.5 in square profile with a sturdy 3/16 in wall and a 36 in length. Its main selling point is raw, weldable carbon steel that performs well when cut, drilled, or welded into frames and machine supports.

Key Features

• High-strength carbon steel: Provides reliable structural integrity for frameworks and machine supports where durability matters.
• 1.5 in height, 3/16 in wall: The specific dimensions offer a good balance of stiffness and weight for medium-duty applications.
• 36 in length: A convenient 3 ft stick that is easy to handle in a garage or shop and fits common project layouts.
• Ready for modification: Uncoated surface accepts welding, drilling, and cutting without special preparation beyond standard shop practices.
• Durable and sustainable: Engineered for wear resistance and is fully recyclable, which suits long-term installations and eco-conscious builds.
• Multipurpose use: Works well with tubing connectors and fittings for harnesses, machine fab, and model materials.

Who It's For

This tubing is best for metalworkers, small fabricators, and serious hobbyists building frames, jigs, or machine supports who want a predictable, weldable piece of raw steel. Its dimensions and wall thickness make it suitable for projects that need moderate load capacity without the complexity of custom machining.

Those who need a corrosion-free finish out of the box or very tight dimensional tolerances for precision instrumentation may want to look at pretreated or cold-drawn alternatives. Buyers also wanting lengths longer than 36 in per piece should consider ordering multiple pieces or longer-stock options elsewhere.

Pros & Cons

Pros

• Good material quality that customers praise for strength and functionality in practical builds.
• Ready-to-modify uncoated surface simplifies welding and cutting operations in a typical shop workflow.
• Dimensionally useful 1.5 in square and 3/16 in wall for medium-duty structural tasks and machine mounting.
• Recyclable and engineered for resistance to wear, making it a durable choice for long-term use.

Cons

• Surface corrosion resistance receives mixed feedback, so parts may require surface treatment for outdoor or humid environments.
• Single 36 in length may be limiting for larger projects without splicing or additional pieces.

Specifications

Material	Carbon steel (ASTM A-36, A500/A513 implied)
Shape	Square tubing
Height	1.5 in
Wall thickness	3/16 in
Length	36 in
Finish	Uncoated, ready for modification

Our Verdict

For builders needing a straightforward piece of structural steel, this 1.5 in x 3/16 in x 36 in square tubing is a pragmatic choice that delivers on strength, workability, and value. It is especially good for shop fabrication, machine supports, and architectural metalwork when buyers are prepared to apply any required corrosion protection for exposed installations.

Frequently Asked Questions

Can this tubing be welded?
Yes. The uncoated carbon steel surface is suitable for common welding methods after standard shop preparation.

Is the tubing rust-proof?
No. Customers report mixed rust resistance; for outdoor or humid use, apply paint or other corrosion protection.

What is the length and wall thickness?
The tube measures 36 in long with a 1.5 in square profile and a 3/16 in wall thickness.