Steps to a More Effective Power Tool Cleaning

Steps to a More Effective Power Tool Cleaning Presented by: Earl Bowry, Jotun Paints, Inc

Introduction • This webinar will explain power tool cleaning and how to effectively remove loose rust, loose mill scale, and loose paint. – The presentation will describe two types of power tools, electrical and pneumatic – It will describe how the use of high efficiency particulate air (HEPA) will reduce air pollution – It will describe how power tools are used for spot cleaning of damaged coatings, when contamination of adjacent areas by abrasive is unacceptable and when a surface-tolerant coating such as oil-based paint is to be used

Power Tool Cleaning • Is a method of preparing steel surfaces by the use of power assisted hand held tools

Power Tool Cleaning • Cleans by impact, abrasion or both • Used frequently for spot cleaning of damaged coatings • Is commonly used to clean difficult to reach areas or missed areas after abrasive blasting • Is used when other forms of surface preparation are not possible or cost effective

Power Tool Cleaning • Two Basic Types: – Electric – Air Driven

Power Tool Cleaning • Pros: – Can be done in confined areas or where abrasive blasting will damage sensitive equipment • Cons: – Slow and physically tiring for the operator – Power tool cleaning media wears out and has to be replaced during the work

Power Tool Safety • Eye and face protection is required to prevent injury caused by flying particles • Ear protection is required because of the loud, constant noise • Wear gloves, boots and hard hats if the particular job requires it

Power Tool Safety • • Never run electrical tools in wet areas Use ground fault interrupters Use respirators to filter dust and debris Power tools can create sparks, so take care when using near volatile vapors and combustibles

Contractor Safety Responsibilities • Provide proper safety equipment for the job being performed • Train workers to use the safety equipment

Worker Safety Responsibilities • Be familiar with the safety equipment provided • Make sure safety equipment is in good working condition • You are responsible for your actions!!

Owner Safety Responsibilities • Assure that proper safety practices are followed

Types of Power Tools • 3 different types of power tools used for surface preparation: – Impact cleaning tools – Rotary impact cleaning tools

Common Electrical and Pneumatic Equipment • Sanders • Wire brushes, wheels & grinders • Chipping hammers • Scalers • Rotary/Impact tools • Needle guns

Sanders Important note: Grit size and distribution (open/closed) are important factors

Wire Brushes, Wheels & Grinders Important Note: Wire type and hardness are important factors

Chisel Scaler Important Note: Generally used for large scale particle removal

Flapper Wheels Use: Can quickly remove heavy layers of rust and paint.

Rotary/Impact Cleaning

Needle Guns Important Note: Needles can get dull fast and may need to be replaced several times in a work shift

Reduction of Air Pollution • High efficiency particulate air (HEPA) vacuum lines attached to reduce air pollution and collect debris produced in cleaning operation

HEPA • High-efficiency particulate air • HEPA is a type of air filter • To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99. 97% of particles that have a size of 0. 3 micrometers or larger

Specifications • The specifications governing power tool cleaning are: – SSPC-SP 3, Power Tool Cleaning – SSPC-SP 11, Power Tool Cleaning to Bare Metal – SSPC-SP 15, Commercial Grade Power Tool Cleaning – ISO 8504 -3, Hand Power Tool Cleaning

SSPC-SP 1, Solvent Cleaning • SSPC-SP 3, SSPC-SP 11 and SSPC-SP 15 require removal of all oil, grease, dirt, etc. in accordance with SSPC-SP 1, Solvent Cleaning, before cleaning with power tools

SSPC-SP 3, Power Tool Cleaning • Removal of loose rust, loose mill scale, and loose paint to degree specified • Intact materials may remain such as: – Mill scale – Rust – Paint • Materials considered intact if they cannot be removed by lifting with a dull putty knife

SSPC-SP 3, Power Tool Cleaning • Specified when rigorous surface preparation is not required, such as a dry interior

SSPC-SP 11, Power Tool Cleaning to Bare Metal • Remove tightly adherent materials to produce a surface that is visibly free from all rust, mill scale and old coatings • No staining permitted • Slight residue permitted in bottom of pits if the original surface was pitted • Requires a 1 mil minimum surface profile

SSPC-SP 11, Power Tool Cleaning to Bare Metal • Examples of circumstances where this specification may be applied are: – Touch-up of welded or damaged areas of erection assemblies – Reducing volume of hazardous waste produced by abrasive blasting – Cleaning around sensitive equipment or machinery

SSPC-SP 15, Commercial Grade Power Tool Cleaning • Requires the removal of all paint, rust, mill scale and other foreign matter • Allows random staining on 33% of each unit area (9 in 2) • Slight residue permitted in bottom of pits if the original surface was pitted • Requires a 1 mil minimum surface profile

ISO 8501 • Combines hand power tool cleaning in one standard • Has two grades of Cleaning: – St 2 – Remove all oil, dirt and poorly adhering mill scale, rust, paint and foreign matter – St 3 – Same as St 2 but more thoroughly cleaned until a metallic sheen is observed

Surface Profile • ASTM D 4417, Method B (Unless Otherwise Specified) – Digital Surface Profile depth micrometer

Profilometer

Surface Profile: SSPC-PA 17 • Procedure for Determining Conformance to Steel Profile/Surface Roughness/Peak Count Requirements – Describes a procedure suitable for shop or field use for determining compliance with specified profile ranges on a steel substrate

SSPC-VIS 3 • Guide and Reference Photographs for Steel Surfaces Prepared by Powerand Hand-Tool Cleaning

SSPC-VIS 3 • This guide describes the use of reference photographs depicting the appearance of unpainted, rusted, and welded hot-rolled carbon steel prior to and after power and hand tool cleaning • These photographs are intended to be used to supplement the written SSPC power and hand tool surface preparation standards

SSPC-VIS 3 Initial Conditions • Condition A: Steel surface completely covered with adherent mill scale; little or no rust visible • Condition B: Steel surface covered with mill scale and rust • Condition C: Steel surface completely covered with rust; little or no pitting visible

SSPC-VIS 3 Initial Conditions • Condition D: Steel surface completely covered with rust; pitting visible • Condition E: Previously painted steel surface; light colored paint applied over blast cleaned surface, paint mostly intact • Condition F: Previously painted steel surface; zinc-rich paint applied over blast cleaned steel, paint mostly intact

SSPC-VIS 3 Initial Conditions • Condition G: Painting system applied over mill scale bearing steel; system thoroughly weathered, thoroughly blistered, or thoroughly stained

SSPC-VIS 3 Steps • Determine initial condition of steel – Select the photograph of the condition that most closely represents the appearance of the steel to be cleaned • Determine the power tool cleaning level to be achieved (SP 3, 11 or 15) • Select the tool to achieve the specified level of cleanliness • Use the photos in VIS 3 that represent the end condition based on the proper tool and specified level of cleanliness (i. e. , SP 3/PWB)

Summary • Use of portable power tools- pneumatic and electric- is common for cleaning operations. Through careful selection and use of the great variety of power tools and accessories, many cleaning operations can be accomplished rapidly and produce satisfactory surface conditions with reasonable labor costs and good paint life

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