Corrosion Identification in Metalized Aircraft?

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  • Corrosion Identification in Metalized Aircraft?

    Posted by Dan on December 1, 2020 at 2:41 am

    The 108-3 has an increased risk of spar corrosion as a result of Stinson using a different aluminum composition on the -3 from the other variants. How difficult would it be to check for this corrosion on a metalized wing? Also, would a metalized fuselage make identifying corrosion in the tail more difficult or impossible?

    Will Ware (Webmaster ISC) replied 2 years, 1 month ago 3 Members · 3 Replies
  • 3 Replies
  • Bob

    Member
    December 6, 2020 at 9:17 pm

    Until just a week or so ago I was custodian of a metalized Dash Two. Both the wings and the fuselage were metalized with the Ruleto metalizing kits. Assuming a similar kit, the fuselage steel structure should be in good condition – the metalizing kit stands the skin away from the metal tube structure to create a shape the sheet metal can be draped around so there is noplace where water can be held against the steel tube structure. Any water that does get inside the fuselage runs down the belly towards the back and drips out the open area that the tail spring emerges from – the water never touches the steel tube structure. You can inspect the tail post area fairly well from the removeable triangular panels below the horizontal stab on each side, plus up from the tail spring area. You can also look down the tailcone from the cargo compartment area assuming the plane in question has a cargo compartment. As already mentioned, it is not a big deal to drill out some rivits and temporarily remove some metal skin if you feel the need to inspect more closely.

    For the wing, the sheet metal is rivited directly to the wing ribs so inspection is more difficult. As already mentioned one can remove the fuel tanks and/or create new inspection holes for access, plus a boroscope can tell you a lot by carefully fishjng it around from whatever access points you find or make.

    Bob and Pat and Blue Belle the fabric 108-3

  • Dan

    Member
    December 14, 2020 at 1:55 pm

    Bob,

    I am considering the purchase of a metalized 108-3, am not familiar with how intrusive a gas tank removal would be. Do you think a seller would be willing to allow a prospective purchaser to remove the tanks as part of a pre-purchase inspection? Thanks for you very helpful response earlier.

    Dan

  • Will Ware (Webmaster ISC)

    Organizer
    December 14, 2020 at 5:10 pm

    Dan, I would offer to this to the seller. You wish to remove the fuel tanks to inspect for Spar corrosion that has been found on other -3s.

    I would propose this to him/her. Should the inspection reveal no corrosion, and you purchase the aircraft, you would pay for the parts and labor.

    If the inspection did reveal corrosion or you elected to not purchase for what ever reason, you only pay 1/2 of the cost.

    The value to the seller to agree to this is he/she would then know what is in there should they have to market to another buyer.