Background

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. Raw aluminum must be pretreated with an etching primer before applying a base coat of color. While base coat paint can be polished and small spot repairs are relatively easy to do, robustness is rather poor. With even moderate use, the bed is likely to look bruised and worn.

Liquid bed liners

POR15 Bed Liner

The fourth option targets the heavy duty requirements of a truck bed, namely liquid bed liner, either sprayed on or applied by roller/brush. For example, 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 tailgate surfaces with two coats, costs $120.

There are a number of bed liner products that differ somewhat by application method, color, texture, and chemistry. 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.

Product comparison

The following table summarizes the most common bed liner products.

Product nameApplicationColorsChemistryMin size
Al's Linerspray guntintablepolyurethane1.00
Custom Coatspray guntintableurethane0.26
Dupli-Colorroller/brushblackwater-based1.00
Heuculinerbrushblack, graypolyurethane1.00
Linerxtreemespray gunblackEUP blend1.50
POR-15spray/roller/brushblackepoxy1.00
Rust-Oleumspray canblackurethane0.18
T-Rexspray gunblackurethane1.00
U-POL Raptorspray/roller/brushtintableurethane0.26

We selected Raptor because 1) minimum size best fits Ute requirement, 2) coloring system allows exact match to original paint color, 3) roller/brush application is appropriate for flat aluminum panels and can be easily repaired, and 4) the product get uniformly high reviews.

Treatment summary

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 bed liner coating on the walls and stained wood bed floor creates both a vintage appearance and a practical cargo space.

Combination polished aluminum, bed liner coating, and bed wood treatment

The above illustration shows protective coating on the bed walls (grey to match exterior paint with blue outlines), highly polished natural top rails (light gray with yellow outlines), and a wood bed (brown with red outlines).

Raw kit CNC cut aluminum (left) vs matte polished top rails