80/20 Aluminum Extrusion: Comparing Sizes, Styles, and Cheaper Alternatives for Racks & Camper Builds

If you've ever wondered why overlanding rigs and custom camper builds look so clean and modular, there's a good chance they're using 80/20 aluminum extrusion. This stuff is like adult Lego for builders: infinitely configurable, stupid strong, and perfect for creating everything from roof racks to full camper interiors.

But here's the thing: 80/20 Inc. makes dozens of different profiles, and their stuff isn't cheap. For most rack and camper structures, 40 Series metric is a strong default—it's stout where it counts, plays well with M8 hardware, and handles real trail loads. Below is a practical guide to where 40 Series shines, when to mix in other profiles, and how to save money with smart sourcing.

Understanding the 80/20 Series System

80/20 organizes their extrusions into two main categories: fractional (imperial) and metric series. Each has its sweet spot for different builds.

Fractional Series: Built for American Projects

10 Series (1" x 1") The 10 Series is your entry-level workhorse. At 25.4mm square, it's perfect for lightweight applications where you need modularity without bulk. Common uses include:

• Interior camper shelving and storage systems

• Lightweight roof rack accessories

• Tool mounting systems

• Small equipment brackets

The T-slot opening is perfectly sized for standard 1/4-20 hardware, making it compatible with tons of aftermarket accessories. Weight is minimal at about 0.335 pounds per foot, which matters when you're building an overlanding rig.

15 Series (1.5" x 1.5") Capable and proven. At 38.1mm square, 15 Series delivers solid strength and is friendly for DIY builders. Common uses include:

• Secondary frameworks and partitions

• Slide-out drawer systems

• Workbench and storage solutions

• Lightweight roof rack accessories

However, for primary structure on racks and campers, many builders favor 40 Series metric profiles for higher section modulus, better M8 hardware compatibility, and broad accessory support. The 15 Series T-slots accept 5/16-18 hardware if you prefer fractional systems.

Metric Series: European Engineering

20mm Series The smallest metric option works great for detail work and space-constrained builds. It's less common in heavy 4WD applications, but it's perfect for electronics mounting and small accessories.

30mm Series This hits the sweet spot for many van and camper builds. Similar in strength to 10 Series fractional but with different slot spacing that works well with metric hardware.

40mm and 45mm Series A common standard for structural work. 40 Series (40x40, 40x80, 40x120) with 8mm T-slots takes M8 hardware, spreads load better than 15 Series, and holds up to trail abuse. Typical uses include:

• Roof rack main rails and crossbars

• Camper cabins, galley modules, and bulkheads

• Spare, jack, and recovery board mounts

• Sliding beds and heavy cargo trays

Why it's preferred:

• Higher section modulus and torsional stiffness per foot than comparable 15 Series

• Broad ecosystem: 8mm-slot accessories, corner cubes, hidden connectors, hinges

• Fast serviceability: M8 fasteners, common spares, repeatable torque values

45mm profiles step up slot size and wall thickness for extreme duty or long spans and are used selectively when the load case demands it.

Slot Configurations and Specialty Profiles

Not all extrusions are created equal. Beyond basic square tubes, 80/20 makes dozens of specialty profiles:

Multi-slot profiles like the 40-8020 (80mm x 20mm) give you maximum connection points in a flat profile. These work great for mounting panels or creating connection strips.

Corner and angle profiles eliminate the need for separate brackets in many applications.

Tube profiles offer clean aesthetics when you don't need external T-slots.

The key is understanding that more slots doesn't always equal better. Sometimes a simple single-slot profile is exactly what you need.

Real-World Applications in 4WD and Camper Builds

Roof Rack Systems

A 40 Series approach uses 40x80 for perimeter rails and 40x40 for crossbars and load bars. It's stiff under dynamic loads, quiet on-road, and easy to reconfigure. Add a spare or light bar by sliding in M8 hardware. Relocate an awning in minutes without drilling.

Interior Camper Frameworks

For full camper builds, 40 Series serves as the backbone: straight, square, and serviceable. Galley modules, bulkheads, and bed platforms tie into 40x40/40x80 skeletons, then get skinned with composite or plywood. Cabinet hardware integrates cleanly with M8 anchors and hidden connectors.

Drawer and Storage Systems

The T-slot system shines for heavy drawers and trays. It's common to build 200+ lb slide-outs with 40 Series rails and linear bearings, then use 10 Series or plywood for the box to keep weight in check.

Size and Strength Comparison

The Cost Reality Check

Let's talk money. 40 Series (40x40 and 40x80) commands a premium over fractional profiles. Expect a higher per-foot rate and longer lead times on specialty lengths. A 40-foot rack build in 40 Series lands in the mid-to-high three figures for extrusion alone—before brackets, hardware, or cutting.

This is where shopping around and mixing vendors pays off.

Where to Buy: 80/20 and Alternatives

80/20 (Direct)

Highest consistency and the broadest catalog of profiles, connectors, and hardware. Expect premium pricing, excellent documentation, and cut-to-length options. Availability is generally good, but specialty profiles and anodize variants can have lead times.

McMaster-Carr

Stocks 40 Series–compatible metric T-slot (8mm slot) alongside fractional profiles, often 30–40% under 80/20 direct. Quality is excellent, hardware depth is unmatched, and M8 fasteners are one click away. Fast shipping, typically in-stock lengths. Watch for slight slot geometry differences; match their T-nuts and connectors for best fit.

TNutz

Carries 40 Series metric (8mm slot) alongside 10/15 Series at aggressive pricing. 4040 and 4080 profiles pair well with M8 hardware and most Type B accessories. Good day-to-day availability and quick shipping on common lengths; confirm slot type before mixing vendors.

Amazon and eBay Suppliers

Plenty of imported 4040/4080 40 Series. Quality varies, but for non-critical brackets and interior modules, you can save 50–70%. Availability is hit-or-miss and lengths may be limited. Verify slot size and type (many are 8mm Type B; some 45 Series use 10mm slots) so your T-nuts and connectors fit.

Zoro and Industrial Suppliers

Business-to-business suppliers often have better pricing than consumer-focused outlets. Availability is better on bulk orders, and cuts may be limited. If you're buying in volume, check local industrial suppliers who might stock compatible profiles.

Hybrid Building Strategies

Here's the practical takeaway for DIY and pro builders alike: you don't need to use extrusion for everything.

Smart mixing involves using aluminum extrusion for the structural framework and critical mounting points, then filling in with cheaper materials like plywood, steel, or even wood where appropriate.

For example, in a camper galley build:

• Use 40 Series for the main frame structure

• Use 3/4" plywood for cabinet sides and backs

• Use 10 Series or 15 Series for drawer slides and adjustable shelving

• Use standard wood cabinet doors and drawers

This hybrid approach gives you the modularity and precision of aluminum extrusion where it matters while keeping costs reasonable.

How to Choose the Right Extrusion (Quick Guide)

• Vehicle size and span

• Load case and dynamics

• Hardware ecosystem

• Weight vs stiffness

• Budget and availability

• DIY tools and tolerance

Default setups to consider:

• Weekend warrior: 10 Series accessories + 15 Series or 40 Series light rack base.

• Serious overlanding: 40 Series primary structure with quality hardware.

• Expedition camper: 40 Series main frame + plywood/composite infill + budget profiles for cabinets.

• Budget van/camper: imported 4040/4080 for non-critical modules; upgrade critical spans to premium 40 Series.

Hardware and Connection Considerations

Don't forget about fasteners and brackets: they add up fast. On 40 Series, M8 bolts with 8mm T-nuts are the daily drivers. Standard 80/20 brackets can cost $15–30 each, but you can often fabricate simple connections using hardware-store angle brackets and proper T-nuts.

For heavy-duty connections, invest in corner cubes, hidden connectors, and gussets rated for 40 Series. For lighter applications, simple L-brackets and standard bolts work fine.

Quality Differences You Should Know About

Genuine 80/20 extrusion has tight tolerances and consistent T-slot geometry. With 40 Series, most vendors follow the 8mm Type B slot, but there are exceptions.

The aluminum alloy and temper vary, too. 80/20’s 6105-T5 holds threads and resists corrosion in real weather. Some imports use softer stock that dents, galls, or creeps under clamp load.

If precision or interchangeability matters—drawer slides, hinge alignment, rooftop gear—stick with name brands and match slot type. For general framing where a few thousandths won’t matter, budget profiles are fine. Always verify whether you’re buying 8mm (40 Series) or 10mm (common in 45 Series) so your hardware fits.

Getting Started Without Breaking the Bank

If you're new to aluminum extrusion building, start small. Build a simple shelf or accessory mount using cheaper extrusion to get familiar with the system. Once you understand how T-slots work and what hardware you need, you can tackle bigger projects with confidence.

Consider buying a starter kit with various hardware and connectors rather than trying to source everything separately. The learning curve is worth it: once you go modular, it's hard to go back to permanent mounting solutions.

The bottom line: 80/20 aluminum extrusion opens up incredible possibilities for custom 4WD and camper builds, but you don't have to pay premium prices for every application. Mix genuine and alternative sources based on your specific needs, and you'll build better rigs for less money.