Workflow - Aluminum Parts

  • Step 1 - machine the part from raw metal or casting to within tolerance
  • Step 2 - store newly machined parts in water with baking soda (calcium carbonate or sodium bicarbonate)
    • “Aluminum alloys form an oxide film instantly upon exposure to air.” [NASF p. 3]
  • Step 3 - heat treatment
  • Step 4 - honing or polishing or pickling
    • honing - air blast (dry or wet) with 5 micron aluminum oxide (~ 1000 grit)
      • “Wet (sometimes called vapor blasting, vapor or liquid honing) or dry blasting is very effective in removing particulate soil, oxides, and scale (from a previous heat treatment). Blasting can also provide random, uniform micro-roughness, which may contribute to improved adhesion of electroplated deposits. Dry blasting is more severe than wet blasting, because the water acts as a cushion on the impingment of the abrasive particles. The abrasives are usually glass beads, aluminum oxide, silcon carbide, sand, or metal shot of varying particle sizes.” [NASF p. 7]
    • polishing - buff with a cloth wheel with Tripoli abrasive compound. Speeds about 2000 RPM.
    • pickling - acidic treatments on the workpiece to produce a lightly etched surface into which plating crystals can grow
      • acidic pickling using sulfuric acid or muriatic acid. 5-10 oz of acid per 1 gallon of water. Always add small amount of acid to a large amount of water to reduce the boiling of the water . Pickle the part for 1-2 minutes. [Hobbyist p. 18]
  • Step 5 - wash with dishwashing soap
    • Water Break Test - surface of workpiece should sustain a thin film of water. If it beads up, further cleaning is required.
  • Step 6 - Non Etch mild Alkaline (pH 9-11) Soak Cleaner
    • baking soda has pH of 9
    • Borax has pH of 8-9.5
  • Step 7 - electrocleaning - anodic or reverse cleaning (optional)
  • Step 8 - Rinse
  • Step 13 - Rinse
  • Step 14 - Bright Dip (optional)
  • Step 15 - warm rinse
  • Step 16 - rinse
  • Step 17 - Anodize-Sulfuric Acid
  • Step 18 - rinse
  • Step 19 - Neutralize
  • Step 20 - rinse
  • Step 21 - 2-step electrolytic coloring (optional)
  • Step 22 - rinse
  • Step 23 - dye (optional)
  • Step 24 - rinse
  • Step 26 - hot water rinse
  • Step 27 - tungsten disulfide impingment on friction surface wearing
  • Reference
    • [ASM-13A] ASM Handbook Volume 13A Corrosion: Fundamentals, Testing, and Protection ASM
    • [NASF] Aluminum Finishing - AESF Foundation Educational Course NASF
      • Process Outline for Aluminum Anodizing (Type II) p. 3
    • [Hobbyist] Hobbyist Electroplating Made Easy by Randy Nyborg Hobbyist

Step 0 - Workpieces

  • Slide Fit

Step 9 - Deoxidize

  • Degreasing and Deoxidizing Chemistries for Aluminum Alloy Surfaces
    • [ASM-13a p. 1862 of 2597]
  • “Many commercial formulations based on other chemistries exist. Some of these can be found in” S. Wernick, R. Pinner, and P.G. Sheasby, The Surface Treatment and Finishing of Aluminum and its Alloys, Vol 1, 5th ed., ASM International, 1987, p. 220 [ASM-13a p. 1862 of 2597]

Step 10 - Degreasing

  • “Degreasing is performed by dipping the specimen in organic solvents, alcohol, acetone, kerosene, or trichloroethylene, or by wiping with cloths permeated with solvent.” [ASM-13A p. 1903 of 2597]

Step 11 - Etching

  • with Caustic Soda (NaOH)
  • to dissolve the aluminum surface (chemical milling) to within specified tolerances or to produce a surface roughness [NASF p. 5.1]
  • Caustic Soap
    • 1 gallon water
    • 1 oz sodium hydroxide
    • 4 oz trisodium phosphate (TSP)
    • 2 oz sodium carbonate

Step 12 - Desmutting

Step 25 - Sealing

  • “Sealing is usually performed by dipping in boiling water…A 10 min sealing treatment is sufficient to seal the pores completely in boiling water…” (ASM Handbook Volume 13A Corrosion: Fundamentals, Testing, and Protection, p. 1907 of 2597)

Periodic Table of Elements

  • Periodic Table
  • Column 1 - electro positive - give electrons
    • Na = sodium likes to give away electrons
  • Group 7 halogen top right side - electro negative - want electrons
    • Cl = chlorine

Oxidation - Reduction: Transfer of Electrons

  • Oxidation-reduction reaction (abbreviated redox) is any reaction that involves the transfer of electrons from one substance to another
  • Oxidation is defined as the loss of electrons (LEO)
    • generally metals lose electrons to form positive ions
  • Reduction is defined as the gain of electrons (GER)
    • nonmetals gain electrons to form negative ions
  • LEO the lion says GER

Electrochemistry

  • LEO is A GERC (jerk)
    • Loss of electrons is oxidation an Anode (positive terminal)
    • Gain of electrons is reduction a Cathode (negative terminal)
  • Anode - positive terminal
    • lose electrons (loss of mass), or source of electrons
    • An Ox = anode oxidation
  • Cathode - negative terminal
    • gain electrons (gaining of mass)
    • Red Cat = reduction cathode

CSI

Blast Cabinet

Modifications

  1. portable sandblasting cabinet - move to outdoors when blasting
    1. Harbor Freight Mobile Base Cart - HF# 95288
  2. upgrade lighting
  3. shelf to store blasting media
  4. shelf to store dust collection / shop vac

Video Help

  • Ray's Garage - Tacoma Company Upgrades Part 9
  • asdf

Training

  • SSPC.org - The Coatings Society
    • Abrasive Blasting (C7) \$1020

Surface Treatments

Surface Coatings

Anodize

  • MIL-A-8625F, Type II
  • Provides corrosion protection and wear resistance to aluminum parts. Can be applied in a variety of colors or clear for decorative and architectural uses.

References

Brush Anodizing

  • Brush anodizing is a localized application of a colored oxide (aluminum oxide) on an aluminum substrate. The workpiece is the cathode (-) and the brush is the anode (+). Various electrolytic acid solutions can be used, usually sulfuric, which is placed on the brush. A low voltage DC rectifier is used to achieve the equivalent of 3+ amps/ft2 of anodizing contact area.
  • Aluminum Finishing, An AESF Foundation Educational Course, p. 22-3
    • Brush anodizing has a history of about 40 years in the US. The process is portable, not limited by tank size, and can re-anodize components that are already assembled. The process is labor intensive, but can often be justified on the economics when labor savings for assembly/disassembly are taken into account, or if the part is unusually large. As one might expect, the chief applications involve airline and aerospace repair work.
    • The technique utilizes a “brush” as illustrated here. Solution is pumped through the polyester felt or bonnet covers. Stainless steel perforated sheet instead of fabric tool covers are used with the gels. Phosphoric, chromic, sulfuric and hardcoat can be applied using this type of equipment. In some cases, the solution is a gel, instead of a free flowing liquid. The equipment and solutions for brush anodizing are commercially available.
    • Brush Anodizing
    • In the case of a repair job, the surface may first be stripped using a similar brush, reverse polarity, and stripping solution/gel.
    • Typical operating conditions are:
    • Anodize Type CD A/in2 Temp, ℉ Time
      Phosphoric 0.02 60-90 10-12
      Sulfuric 1.5 65-85 0.5-10
      Hard Coat 0.5 30-50 10-30
      Chromic 0.02 95-105 15-60
  • References

Brush Plating

Hard Anodize

Procedure

  • “In general, the anodizing process of an aluminum or aluminum alloy specimen consists of pretreatments (degreasing, etching, and polishing), anodizing, coloring, and sealing.
    • Pretreatments
      • degreasing
      • etching
      • polishing
        • Procedures of etching and polishing
    • Anodizing
      • Procedures of anodizing
    • Coloring - of anodic oxide films is classified into three groups: integral coloring, dyeing and electrolytic coloring
      • electrolytic coloring
        • Electrolytic Coloring
    • Sealing - “Sealing is usually performed by dipping in boiling water…A 10 min sealing treatment is sufficient to seal the pores completely in boiling water…” (ASM Handbook Volume 13A Corrosion: Fundamentals, Testing, and Protection, p. 1907 of 2597)

Surface Coating - Electroless Nickel

  • Provides very high corrosion and wear resistance. Also known as EN.

Standard Specifications

Surface Coating - Tungsten Disulfide

Procedure - Tungsten Disulfide

  • Step 2 - Hone
    • Using 5 micron (800-1500 grit) aluminum oxide powder as a fine abrasive, air blast the part to obtain a uniform matte appearance
    • Equipment
      • Blasting cabinet to reclaim aluminum oxide
      • brush to wipe down workpiece
  • Step 3 - Impingement
    • Using an air blast at <125 PSI and nozzle size, spray tungsten disulfide on the part until you see a uniform silver gray color film appearance
  • Step 4 - tape test
    • “A pressure-sensitive-film-backed tape with an adhesion of not less than 45 ounces per inch (0.49 N/mm), shall be applied to a flat surface of a coated specimen, rolled in place, and rapidly removed in accordance with ASTM D 2510, Procedure B. The lifting of flakes or particles of the coating from the specimen, exposing the basis metal, is not acceptable. A uniform deposit of powdery material clinging to the tape is acceptable.” (AMS2530A 3.4.1 Adhesion)

Specifications - Tungsten Disulfide

  • AMS2530A - Tungsten Disulfide Coating, Thin Lubricating Film, Binder-Less Impingement Applied
  • DOD-L-85645A

Honing

  • Grit to Mesh to Microns Conversion Chart
  • Aluminum Oxide (Al2O3), 5 micron
  • Aluminum Oxide (White Fused) Sandblasting Abrasive, Fine Grades 280 through 1200
  • Illinois Valley Minerals (IVM), LLC is a producer of brown fused aluminum oxide
  • AGSCO Corp in Wheeling IL
    • 50 lbs of #1000 Mesh White Aluminum Oxide at $6.107/lb = $305.35
    • Tom Guzek, tguzek@agsco.com
  • The Stutz Company - distributors of plating processes, chemicals and equipment for the electroplating industry
    • info@stutzcompany.com

Aluminum Oxide

Surface Preparation - Anodize Aluminum

  • Step by Step Procedure
  • Step 1: Cleaning aluminum parts
    • Option 1 - Acid Cleaning - fluoride cleaner consists of sulfuric acid, fluoride and surfactant
    • Option 2 - Sulfuric Acid
      • battery acid is 37% sulfuric acid
      • add distilled water
    • Option 3 - Lye/Caustic Soda (Sodium Hydroxide)
      • 5 grams (0.18 oz) caustic soda
      • 240 mL (1 cup) distilled water
      • soak object 2-4 minutes
      • “Aluminum is rapidly attacked by even dilute solutions of caustic soda at all temperatures.” (ASM Handbooks Online - M.Davies, Corrosion by Alkalis, Corrosion: Environments and Industries, Vol 13C, ASM Handbook, ASM International, 2006, p 710–726)
    • Graham's Salt (Sodium Polyphosphate)
    • Washing Soda or Soda Ash (Sodium Carbonate) used in swimming pools to raise pH
  • Step 2: degrease aluminum parts with any degreaser such as Simple Green
  • Step 3: de-smut the aluminum part
  • Step 4: Anodize in the acid bath at 12 amps/square foot for 45 min, keep temp at 70-72 degrees F
  • Step 5: remove parts from acid bath and rinse with distilled water
  • Step 6: Dye parts in warm dye, 100-140 degrees F
  • Step 7: Seal parts by placing in boiling distilled water for 20-30 minutes
    • asdf

Dave Mills Cleaning Procedure

  • Alkaline solution with agitation
  • Clean water rinse with agitation
  • Warm air dryoff
  • [Q] do you recommend using a fish tank air bubbler to agitation the solution, could I just submerge an air hose?

Reference Standards

Education

Chemical Manufactures and Resellers

I got your contact info from https://www.lvf.com/industrial/contact-us.html

I'm working on a new business venture on surface treatments (e.g. anodizing aluminum) and will be buying substantial quantities but currently need small quantities for lab work. What is the minimum sample quantities I could get or minimum purchase amount for the following:

Aluminum Sulfate Copper Nitrate Oxalic Acid Potassium Permanganate Nitric Acid Sulfuric Acid

I reached out to Thatcher Company, they don't sell in small packages and suggest contacting you, Land View in Rupert,

thanks,

Jeff Jensen

Industry

Employment

    • Powder Coater
      • Powder Coater
        • Mountain Home, Idaho
        • In The Ditch Towing Products is the fastest growing manufacturing company in Idaho and we have an opportunity for a passionate, energetic person to join our Powder Coating/Paint Department. All you need is a desire to learn and a hunger to want to build a career.
        • We are currently seeking someone for the powder coating department to prepare product for painting, powder coat products to a high standard, check for defects in finish, and take necessary actions to correct those defects. The sky’s the limit in this position with unlimited opportunity for advancement. If you have great attitude and a desire to get better every day, we would love to teach you the skills you will need to succeed here. If you want to work in a clean organized shop that believes in helping people get what they want; this may be the job for you.
        • Here at In the Ditch, we are a privately owned business that’s been in Mountain Home for over 20 years with no plans to move. We have found great success by recruiting people who are excited about working here and buy into our culture. We truly believe in coaching and developing people who have a great attitude, work ethic and want to leave their mark on the world. At In The Ditch, we value people for their Enthusiasm, Commitment, Hard Work and Ability to do things better each day, not just for their certifications and degrees or for the buzzwords on their resumes. We love candidates that believe that our only opportunity to win in the marketplace will come by hiring and retaining the best people in the industry. If you have the desire to help us build a great company and want to surround yourself with people who share the same vision, please apply today.
        • Job Details:
          • Hold or position powder coat guns to directly spray onto products
          • Attach hoses or nozzles to machines, using wrenches and pliers, and make adjustments to obtain the proper dispersion of spray
          • Powder coat items and perform touch-up painting, using paint brushes
          • Set up and operate machines to powder coat a wide variety of metal products
          • Remove grease, dirt, or rust from surfaces in preparation for powder coating application using abrasives, solvents, brushes, washing, or sandblasters
          • Apply powder coating to protect product surfaces, using powder coatings guns
          • Place coated products in ovens for specified times to harden finishes
          • Place items or products on racks to coat or spray them, using hands or hoists
          • Inspect finishes of workpieces or finished products to ensure quality
          • Clean machines, related equipment, and work areas, using water, solvents and other cleaning aids
          • Transfer completed items or products from machines to drying or storage areas, using handcarts, or racks
          • Provide a great level of attention to detail and focus on given tasks
          • Drive fork lift to load/unload items as needed
          • Assist with other tasks as given
Navigation

Civil Engineering Engineering - Computer Engineering - Electrical Mechanical Engineering

Print/export
QR Code
QR Code engineer-mechanical:surfacetreatment (generated for current page)