Aluminum Alloy 101
Aluminum Alloy 101 – What is aluminum alloy?
Aluminum alloy is created when other elements are added to pure aluminum in order to enhance its properties, usually to increase strength. These elements include copper, silicon, iron, magnesium, manganese and zinc, and can make up as much as 15% of the alloy by weight. Different alloys are given a four-digit number which we then use to identify its characteristics.
Most common alloys for your trailer restoration
The most commonly used aluminum for exterior panel replacement is .032 thick, 2024T3 Alclad. This is the most well-known of the high strength alloys and known as "aircraft aluminum”. With its high strength and excellent fatigue resistance, it is best used where a good strength-to-weight ratio is desired. It is easily polished to a high shine. 2024 is commonly used with an anodized finish or in clad form. (This material is also used for interior panels in .032 thickness) Airparts, Inc. offers this material in continuous lengths both 48” and 60” wide, as opposed to just 4ft x 12ft sheets, you can have long runs with fewer seams.
Anodized vs Alclad
Anodizing is "controlled oxidation”, speeding up the naturally occurring phenomenon that happens to aluminum over time. Anodizing is an electrochemical process that converts the metal surface into anodic oxide finish by immersing the aluminum into an acid electrolyte bath and passing an electric current through, creating the oxide finish. Anodized aluminum cannot chip or peel, it porous and allows for secondary processes such as coloring and sealing.
Alclad is a pure layer of thin, high-quality aluminum that is bonded to the aluminum. Alclad helps with corrosion resistance. Alclad is usually a "film” 2.5% to 5% of the total thickness of the material and not only protects it from corrosion but also has a galvanic effect to further protect the core material.
5052H32 "Belly Pan Aluminum” .025 thickness
5052H32 is one of the highest
strength of NON-heat-treatable alloys. It is important to know that it is
NON-structural. 5052 has excellent corrosion resistance and is very common in
marine applications. The bendable/workable characteristic of this aluminum
along with good corrosion resistance makes it desirable for belly pan aluminum.
This aluminum has a satin/mill finish and can be used to laminate over existing
walls or cabinets for cosmetic purposes, but is not recommended for anything
structural. Airparts, Inc. offers this material in continuous
lengths as opposed to just 4ft x 12ft sheets, most people run panels widthwise
across the trailer making a seam every 48” for ease of future access.
6061T6 – an interior option
6061T6 is a structural alloy, in .032 thickness is a good alternative to 2024T3 for interior panel replacement. 6061 is lessor expensive and has a nice satin/mill finish if you prefer a softer look interior than the brighter 2024T3. If you are going to paint the interior, 6061 makes sense from a budget standpoint.