Written by Stucco Champions — Southern California’s Authority on Exterior Plastering.

Different Stucco Trowels and Their Guide: The Extension of the Hand

In the trade of plastering, the trowel is not just a tool; it is an extension of the artisan's hand. The texture, smoothness, and density of your stucco wall are determined entirely by the piece of steel pushing the mud. Using the wrong trowel can result in "chatter marks," rust stains, or uneven hydration.

Whether you are a DIYer patching a crack or an apprentice learning the ropes, understanding the metallurgy and geometry of your tools is critical. This guide breaks down the essential trowels used in Southern California stucco application.

1. Metallurgy: Choosing the Right Steel

Trowels are forged from different metals. Each reacts differently to the chemistry of Portland cement.

Stainless Steel (The Finisher)

Best For: White or light-colored finish coats.
Why? It does not rust. If you use a standard carbon steel trowel on a white "Santa Barbara" finish, microscopic rust particles can embed in the wall, leaving orange streaks months later. Stainless steel eliminates this risk. It keeps its shape and is easy to clean.

Blue Steel (The Burnisher)

Best For: Hard-troweled smooth finishes and interior plaster.
Why? Blue steel is thinner and more flexible than stainless. It allows the plasterer to "feel" the wall and apply extreme pressure to burnish (polish) the surface without leaving drag marks.
Note: It rusts easily if not oiled after every use.

High Carbon Steel (The Workhorse)

Best For: Base coats (Scratch and Brown).
Why? It is incredibly durable and rigid. It can handle the heavy abrasion of coarse sand used in base coats. Since the base coat gets covered, minor rust spots are not a concern.

2. Blade Shapes: Square vs. Rounded

The shape of the blade dictates how the mud is manipulated.

The Square Trowel (Pipe Trowel)

The Look: Rectangular with sharp 90-degree corners.
Use: Applying base coats, laying material into corners, and "rodding" small areas.
Drawback: The sharp corners can dig into the finish, creating "cat faces" or gouges if the user isn't careful.

The Pool Trowel (Rounded)

The Look: Rectangular with rounded, curved ends (like a pill shape).
Use: Finish coats and smooth textures.
Why We Love It: The rounded ends prevent the tool from digging in. This allows the plasterer to make sweeping arcs without leaving "lap marks" or lines in the texture. Despite the name, it is the standard tool for modern smooth stucco, not just swimming pools.

3. Detail Tools: Getting into the Corners

You cannot finish a house with just a 14-inch trowel.

• Margin Trowel: The small, rectangular "bucket scoop." Essential for mixing small batches, cleaning the hawk, and patching tight areas around pipes.
• Pointing Trowel: Triangular shape. Used for detailed repair work and getting into sharp internal angles.
• Corner Trowel: Shaped like an "L." Used to create perfect 90-degree inside or outside corners.

4. The Hawk: The Material Holder

You can't trowel without a hawk. This is the flat square board that holds your mortar.
Recommendation: Buy Magnesium. It is lighter than aluminum and durable. In plastering, saving a few ounces of weight on your arm makes a massive difference over an 8-hour day.

5. Breaking in a New Trowel

A brand new trowel is often too sharp. The edges can slice the building paper or leave razor-thin lines in the mud.
Pro Tip: Before using a new trowel on a finish coat, sand the edges lightly or use it on a rough base coat for a few days to dull the "factory edge."

Conclusion: The Right Tool for the Layer

Use Carbon Steel/Square Trowels for the structural gray coats to move heavy mud. Switch to Stainless Steel/Pool Trowels for the white finish coats to ensure a clean, rust-free, smooth texture. Using the right metal for the right layer is the mark of a professional.