The aluminum sheet bed walls — including the tailgate inner wall — can be finished a number of ways.
First, the walls can be left “natural”. The disadvantage is that aluminum will oxidize over time, especially when exposed to the elements, leaving a blemished appearance. Even polishing aluminum is only temporary unless clear coat is applied immediately afterwards.
A second option is anodizing. This chemical process bonds to the metal surface for a very durable coating. A “clear” anodize treatment depends on the alloy chemistry, ranging from gray to a more brownish tint. Also, different lots can have slightly different tints.
For a more uniform color (or something different than some shade of gray), a dye can be used in a variety of colors. However, this dye process is sensitive to UV radiation so clear coating afterwards is highly recommended. A disadvantage is that scratches are difficult to repair, especially with a clear coat applied over the anodized surface.
Anodizing all the large aluminum surfaces becomes rather expensive; typical quotes run $21-22 per square foot. To cover just the exposed truck walls without the tailgate requires over 21sf so expect to pay $600 or more.
A third option is to apply automotive paint or some other liquid coating. A heavy duty choice would be a brush-on material like POR15 Bed Liner that has rubberized epoxy ingredients (the exact contents are a trade secret). A gallon of POR15, sufficient to cover all the ute’s walls and inner tailgate surfaces with two coats, costs $120.
Al’s Liner is a similar spray-on three-part polyurethane coating ($100) that can be tinted to match any color (except white) by swapping out the kit’s base tint with 8oz of automotive paint (urethane, acrylic or waterborne but no binders) in the color you want.
The three extruded aluminum floor pieces included in the Smyth kit are difficult to polish, but practical: if damaged, replacement is a simple process. We are considering a wood floor; see wood bed discussion for more details.
Combining a natural polish/clear coat epoxy on the top rails with a protective wall coating and stained wood bed creates both a vintage appearance and a practical cargo space.
The above illustration shows protective coating on the bed walls (black with blue outlines), highly polished natural top rails (light gray with yellow outlines), and a wood bed (brown with red outlines).