Results 1 to 9 of 9

Thread: Sanding/Striping paint off spring steel landing gears

  1. #1

    Join Date
    May 2012
    Location
    San Diego, California
    Posts
    2

    Sanding/Striping paint off spring steel landing gears

    I have a 1956 Cessna 180 and would like to temporarly repaint the landing gear until I can have a complete paint job. I have received comments from mechanics, experienced individals etc., equally with polar opinions. Some say sanding gently into to steel of the gear to remove the corrosion is OK, just don't leave any grooves, or perpendicular scratches to the grain. Others have responded to never sand the spring steel Cessna gear at all, ie, do not remove any surface material or 90% of the spring steel tensile strength is gone. Use only glass bead sand blasting, etc.

    Any thoughts or experience out there on this topic? I am attempting to get a good education on this.

  2. #2

    Join Date
    Oct 2011
    Location
    WA
    Posts
    345
    Paint stripper will remove the paint. The rust that remains can be sanded off with fine sandpaper (400).
    A smooth sanded surface is better than rust pits for fatigue cracking. Done this many times on Cessna 180's.
    Don't worry about the slight metal removed.
    But in any case, always check the Cessna service manual first.

  3. #3

    Join Date
    Aug 2011
    Location
    Wachapreague Va.
    Posts
    120
    Soda blasting will remove both paint and rust with no damage.

  4. #4

    Join Date
    May 2012
    Location
    San Diego, California
    Posts
    2
    Bill and vaflier, Thank you both for your comments. I will also check with the Cessna service manul.
    towpilot

  5. #5

    Join Date
    Jul 2011
    Location
    Clarklake, MI
    Posts
    1,182
    Quote Originally Posted by towpilot View Post
    I have a 1956 Cessna 180 and would like to temporarly repaint the landing gear until I can have a complete paint job. I have received comments from mechanics, experienced individals etc., equally with polar opinions. Some say sanding gently into to steel of the gear to remove the corrosion is OK, just don't leave any grooves, or perpendicular scratches to the grain. Others have responded to never sand the spring steel Cessna gear at all, ie, do not remove any surface material or 90% of the spring steel tensile strength is gone. Use only glass bead sand blasting, etc.

    Any thoughts or experience out there on this topic? I am attempting to get a good education on this.
    You can sand the gear to remove old finish and any corrosion. Make sure you use aluminum oxide only. 150 grit is good for corrosion removal and blending, 400 grit for finishing. If you don't have experience doing this, do it by hand, no power tools. Check for any pitting in the finish, the new Cessna aging aircraft criteria has limits for pitting depth and it's not much. I think you can blend anything up to that depth out at 20:1. I can check the specifics when I get home. Do NOT use acid based paint stripper on your gear legs, due to the potental for hydrogen embrittlement.

  6. #6

    Join Date
    Sep 2011
    Posts
    288
    I have never done spring landing gear but I do like crushed glass as a medium as it does a great job.. It doesn't have the contaminates like raw silica sand or even black beauty. I have used wheat starch and it takes off paint but is of little use on rust. Maybe someone had a better medium than I did.
    Last edited by RV8505; 05-22-2012 at 12:59 PM.

  7. #7

    Join Date
    Aug 2011
    Location
    FA40
    Posts
    412
    Quote Originally Posted by RV8505 View Post
    ... crushed glass...doesn't have the contaminates like silica...
    stupid me. i thought glass IS silica:

    "Silica is a common fundamental constituent of glass."

    http://en.wikipedia.org/wiki/Glass

    "Any corrosion on the surface of a highly stressed steel part is potentially dangerous, and the careful removal of corrosion products is required. Corrosion products must be removed by careful processing, using mild abrasive papers such as rouge or fine grit aluminum oxide, or fine buffing compounds on cloth buffing wheels."

    faa-8083-30 chapter 6

    "4.3.4 CORROSION REMOVAL. Abrasive blasting is the preferred method of removing corrosion; other mechanical methods (SSPC SP-2 or SSPC SP-3) that may be used are grinding, chipping, sanding, or wire brushing. Chemical corrosion removal may be used when there is no danger of the chemical becoming entrapped. Phosphoric-acid- type remover must not be used on high-strength steel heat treated above 1.24 gigapascals (GPa) [180,000 pounds per square inch (psi)] tensile strength because of possible stress corrosion or hydrogen embrittlement problems."

    NASA tech manual 584c

    your mileage may vary.

  8. #8

    Join Date
    Sep 2011
    Posts
    288
    Sorry I meant raw silica sand.

    I have never done spring landing gear but I do like crushed glass as a medium as it does a great job.. It doesn't have the contaminates like raw silica sand or even black beauty. I have used wheat starch and it takes off paint but is of little use on rust. Maybe someone had a better medium than I did



    http://newageblastmedia.com/


    What is New Age Blast Media®?
    New Age Blast Media® is an alternative 100% recycled glass sandblasting media that directly benefits the environment while eliminating the health risk of airborne carcinogens-giving a modernistic approach to sandblasting abrasives.
    Recycled glass blasting media has been successfully substituted for silica sand and other blasting media in shipyard trials and in other construction projects and equipment cleaning. New Age Blast Media® competes with common abrasive alternatives as well as niche materials such as plastic pellets used on sensitive surfaces. Glass can be used as a dry blasting media or combined with water for use in slurry blasting.
    In addition to worker safety benefits, New Age Blast Media® works great for sandblasting thick or soft coatings, aluminum, brass, bright metal, and "spot and sweep" applications.
    Cleaner: New Age Blast Media® is manufactured from 100% Recycled Container Glass that directly helps reduce landfill waste and limits the use of more toxic slags. It is non-reactive and inert, and can be used near and around water.
    Safer:New Age Blast Media's® dust is classified by OSHA/NIOSH as "nuisance" dust. Contains less than 1% free silica unlike most coal slags and has virtually none of the OSHA identified Heavy/Toxic Metals associated with slags and some other mineral abrasives.
    Silica sand blast media in its natural state has a crystalline structure that has the capacity of “sticking” to lung tissues. Our recycled glass blast media is amorphous with a closed structure that doesn’t absorb anything and doesn’t physically stick to tissues. If a person is exposed to amorphous glass fines or dust, the body can expectorate the dust as it would any other type of natural dirt.
    Faster:New Age Blast Media's® crushed glass delivers a natural, whiter metal finish that many other sandblasting abrasives. Significantly less embedment issues—up to 5 times less than slag blast media. Crushed glass blast media's dust is translucent, which allows for increased visibility and operator production!
    Novetas Solutions believes that what a company stands for is as important as what it produces. We provide our customers with numerous ways of obtaining information and sending us their feedback. We encourage customers to contact us with their feedback, comments and questions and our customer service department will contact you within 48 hours.
    Last edited by RV8505; 05-22-2012 at 01:10 PM.

  9. #9

    Join Date
    May 2012
    Posts
    10

    100 series manintenance manual

    Temporary revision TR5 on the pre-1962 Cessna 100 series maintenance manual, p/n D138-1-13, specifies the procedures for cleaning rust from the gear legs. Basically NO chemical stripping. Top suface pits can be sanded to a max depth of .063". Bottom suface to a max .012" depth before having to re-shot peen.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •