Flash Rust » cleanliness

Summary of Major Points

charles frenzel — Mon, 16 Mar 2009 19:32:56 +0000

Summary of Major Points:
1.    Flash Rust is the rust that occurs from the time the waterjetting process starts to the time the water used for the waterjetting process dries.
2.    Control the quantity of Flash Rust by Project Planning
          • During Removal Process
          • As Water is drying
          • Keep the drying time to a minimum.
3. Remove excess loose Flash Rust prior to Painting

4. Based on the subjective methods, Flash Rust is classified as
           • None
           • Light
           • Moderate
           • Heavy

The following metric table was developed by Pete Ault, Elzly Technology Corporation. Click Table to enlarge.

Table of Metrics used in Flash Rust

ALL of the VISUAL GUIDES are used in the SAME WAY!
 Look at the flash rust
• straight on,
• within arm’s length,
• in good lighting,
• prior to painting.
 Allow time to remove, if necessary, excess loose flash rust prior to painting

Look at the surface and decide if you can see through the rust or if it obscures the surface. Make sure that the rust is not splotchy black.

Look at the color. Color can vary depending on the type of steel. The color is affected by the age and type of steel and, in the field, certainly might appear differently than the descriptive terms. Current language being adopted by NACE and SSPC will remove the COLOR language.

Determine Quantity of loose rust dust. Lightly wipe the surface with a cloth.

The methods to evaluate Flash Rust are Subjective.
• Visual Appearance and
• Assessment of amount of Loose Dust
 Cloth Wipe in hand
 Cloth Swatch in hand
 Cloth around a Brush
 Tape

Example of Heavy Flash Rust Swatch

charles frenzel — Sun, 15 Mar 2009 23:08:24 +0000

Example of Moderate Flash Rust Swatch:

 Easy to prepare the swatches.
 Keeps a constant light pressure.
 Gives a clear distinction between light, moderate, and heavy.
 The color transfers to only the cloth that is in contact with the surface. It can be difficult to interpret the various spots of color.

Wipe or Sweep with Cloth Held in Hand

charles frenzel — Sun, 15 Mar 2009 17:20:00 +0000

Wipe or Sweep with a Cloth held in a hand

 Make a bundle of cloth in your hand.
 Swipe the dry cloth across the surface.
 Make one swipe, up or down or sideways with the cloth touching the surface.
 Try to avoid pressing the fingers against the surface.

The following four pictures are examples of hand held wips and light flash rust.

Close up of two Light Flash Rust cloths.

In the two pictures above, the top one shows transference where the fingertips met the surface. There might be some color, but not much.

VIS Guides for Visual Cleanliness

charles frenzel — Sun, 15 Mar 2009 16:52:15 +0000

Use of VIS Guides for Visual Cleanliness

Immediately after the cleaning, before the surface has flash rusted, (it might still be wet), evaluate the degree of Visual Cleaning.
The visual cleaning evaluation often occurs while the surface is still wet.

Courtesy Dr. Lydia Frenzel

A section was cleaned with hand-held lances over a period of 3 days. Then the jetters moved to another section. The visual cleanliness was evaluated at the time of coatings removal. The flash rust was evaluated on the day that it was painted.

Example of Visual Cleanliness (Thorough Cleaning) (Below).
Example of Moderate Flash Rust – at time of paint application.
Photo Courtesy of Dr. Frenzel

Conditions at time of Cleaning/Conditions prior to Cleaning

Example of Visual Cleanliness (Thorough Cleaning).
Example of Moderate Flash Rust – at time of paint application