How Thick Is .125 Aluminum?

How Thick Is .125 Aluminum?

When working with aluminum sheets, plates, or foils, understanding thickness is critical for project success. A common specification like .125 aluminum (or 1/8-inch aluminum) raises questions about its exact dimensions, applications, and alternatives. Here’s a detailed breakdown.

.125 Aluminum Thickness Explained
The term “.125 aluminum” refers to material that is 0.125 inches thick. Converting this to metric units:

Millimeters: 0.125 inches = 3.175 mm (commonly rounded to 3.18 mm or 3.2 mm)
Gauge: Approximately 8 gauge (U.S. Standard Gauge for non-ferrous metals)
This thickness is popular in industrial and DIY projects due to its balance of strength and workability.

Common Uses of 0.125-Inch-Thick Aluminum
1. Metal Fabrication
Structural components: Brackets, frames, and supports
Machined parts: CNC-friendly for prototypes or custom tools
2. Automotive & Aerospace
Body panels, trim, and lightweight shielding
3. Construction
Roofing, siding, and HVAC ductwork
4. DIY Projects
Custom signs, shelving, and outdoor furniture
How 0.125 Aluminum Compares to Other Thicknesses
Thickness (inches) Thickness (mm) Typical Use Case
0.032 (foil) 0.81 mm Food wrapping, insulation
0.063 (1/16") 1.6 mm Crafts, light-duty enclosures
0.125 (1/8") 3.18 mm Structural parts, automotive panels
0.25 (1/4") 6.35 mm Heavy machinery, marine applications
Key Factors When Choosing .125 Aluminum
Alloy Type

6061-T6: High strength, ideal for welding and machining.
5052-H32: Corrosion-resistant, perfect for marine environments.
3003: General-purpose, excellent for forming.
Width & Length
Standard sheets range from 12x12 inches to 48x96 inches, but custom cuts are available.

Temper

H32: Strain-hardened for stability.
T6: Heat-treated for maximum hardness.
FAQs About .125 Aluminum Thickness
Q: Can I bend 0.125-inch aluminum by hand?
A: Yes, with proper tools. Use a brake press for sharp bends or a mallet for gradual curves (depending on alloy hardness).

Q: How much does a 4x8 ft sheet of .125 aluminum weigh?
A: Aluminum weighs ~1.45 lbs per square foot. A 4x8 ft sheet (~32 sq ft) weighs approximately 46.4 lbs (21 kg).

Q: Is 3.18 mm aluminum thick enough for outdoor use?
A: Yes, especially if using weather-resistant alloys like 5052 or coated options.

Buying Tips for 0.125-Inch Aluminum
Verify Tolerances: Industrial-grade sheets may vary by ±0.005 inches.
Check Finish: Mill finish (raw) vs. brushed/anodized for aesthetics.
Compare Prices: Costs range from
20
–
20–60 per sheet (depending on alloy and supplier).