Stamped Aluminum Rib Prep

Discussion in 'Maintenance Bay' started by ilpilot, Apr 10, 2020.

  1. ilpilot

    ilpilot Filing Flight Plan

    Joined:
    Dec 26, 2018
    Messages:
    29

    Display name:
    ilpilot
    Greetings POA,

    I am in the process of rebuilding my wings off of a '46 Taylorcraft BC-12D. Doing a variation of the swick and cole conversion.

    This is my first build, and I'm looking for advice regarding the wing ribs.

    They are in pretty good shape. In many similar builds that I've seen, the ribs were primed with some form of primer/paint.

    Wondering what you guys think. Should I acetone the ribs, and reprime them? Acetone/scotchbrite/reprime? Just acetone clean and call it a day?

    Appreaciate any and all advice. Thank you!
     
  2. murphey

    murphey Touchdown! Greaser! PoA Supporter

    Joined:
    Aug 21, 2008
    Messages:
    10,608
    Location:
    Colorado

    Display name:
    murphey
    Not a building, but I vote for primer. Another layer of insurance against corrosion.
     
    ilpilot likes this.
  3. ilpilot

    ilpilot Filing Flight Plan

    Joined:
    Dec 26, 2018
    Messages:
    29

    Display name:
    ilpilot
  4. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    I would not use scotchbrite,, It scratches.
    I would fabricate a tray to soak them in epoxy remover, then use a brush to any dirt/grime. then wash and rinse, after the ribs are dry use a Stainless steel platers brush to any corrosion, and leave bare.
     
  5. murphey

    murphey Touchdown! Greaser! PoA Supporter

    Joined:
    Aug 21, 2008
    Messages:
    10,608
    Location:
    Colorado

    Display name:
    murphey
  6. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
  7. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    BTDT a few times. :)
     
  8. ilpilot

    ilpilot Filing Flight Plan

    Joined:
    Dec 26, 2018
    Messages:
    29

    Display name:
    ilpilot
    Thank you all. Tom, I happen to have lots of Xylene and Acetone on hand. Would that be an appropriate substitute for cleaning the ribs?

    And just to I know I understand, after cleaning, you suggest not using a primer at all?

    Thank you very, everyone, for helping a beginner like me!
     
  9. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Ribs, and primers, be careful, many the fabric systems you can't paint and get good adhesives.

    It really depends upon which fabric you use, which coating can be used.
     
  10. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Anything that will leave the surface clean and dry.
    most stripers are a super soap soluble with water .
    I use a stripper because it removes all old glues.
     
  11. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    never use metal brush to remove anything except S/S to remove corrosion
     
  12. Bell206

    Bell206 Final Approach

    Joined:
    Oct 6, 2017
    Messages:
    5,247

    Display name:
    Bell206
    Are all the ribs bare aluminum now? Original? Whether to prime will depend on operating environment, personal preference, and as mentioned above, what fabric covering method will be used. In general, I use a good 2 part epoxy primer on metal wings and use the fabric system recommended primer on fabric wings. Regardless, aluminum needs a specific prep to ensure proper paint adhesion which consists of a cleaner/conditioner (e.g., Alumiprep/Bonderite 33) and a conversion coating (e.g., Alodine 1201/Bonderite 1201). You can use your Xylene/Acetone stock to pre-clean the ribs prior to the Bonderite prep. If water still beads on the rib surface after the Alumiprep stage you can use some red scotchbrite to help clean but usually the Alumiprep works on its own, unless there is some existing corrosion areas. Also, if you're not the one who be signing off the work, you should keep whoever is updated to the methods you will use. Good luck.
     
  13. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Post #1 says they are working on a 46 T-crate. That is a certificate aircraft, There are several STCed fabric systems which must adhered to.
    Or you can still do dope and cotton, that is the glue. (no paint)this gives an ability to see thru the wing for inspections
     
  14. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Correct me if I am wrong but isn't that a CLIP WING version?
     
  15. Bell206

    Bell206 Final Approach

    Joined:
    Oct 6, 2017
    Messages:
    5,247

    Display name:
    Bell206
    Perhaps you might want to start another thread on fabric stuff so as not to skew this one? But to answer your question, yes, you can still do dope and cotton via a 337, but it's usually more expensive than using Stewarts or Stits. As to "see-through" cotton wings never saw one. All the cotton wings I saw had aluminum dust/dope coatings. But then again I'm not that old....;)
     
    Doc Holliday likes this.
  16. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Dope/Cotton is the Original fabric. the 337 is for the major repair. any other system does require STC.

    When I change the subject I'll let you know.

     
    Last edited: Apr 11, 2020
  17. JAWS

    JAWS Cleared for Takeoff

    Joined:
    Oct 7, 2016
    Messages:
    1,190

    Display name:
    JAWS
    Poly Fiber has a nice manual. It specifically states what to use on aluminum, steel, etc. I am only familiar with the Poly Fiber process (and that was many years ago!), but I am sure the other systems have similar guidance.
     
  18. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    That is a great product, it is labor intensive, it was called the Stiz (sp) ceconite system, Ray Stiz(SP) then A&SS bought it product.

    Google " aircraft fabric systems" to get a whole list
     
  19. ilpilot

    ilpilot Filing Flight Plan

    Joined:
    Dec 26, 2018
    Messages:
    29

    Display name:
    ilpilot
    Correct. Wings are cut down to about a 27' span total. Wingtips squared off. Lycoming O-320 up front. Should be fun :)
     
  20. kyleb

    kyleb Final Approach PoA Supporter

    Joined:
    Jun 13, 2008
    Messages:
    6,521
    Location:
    Marietta, GA

    Display name:
    Drake the Outlaw
    Is this aircraft going to be hangared? If so, I'd clean and alodyne the ribs and be done with it. Epoxy primer = weight, time, and money.
     
    Tom-D likes this.
  21. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Has this aircraft been done prior ? or are you still doing the major modification?
     
  22. ilpilot

    ilpilot Filing Flight Plan

    Joined:
    Dec 26, 2018
    Messages:
    29

    Display name:
    ilpilot
    Doing all modifications here in the shop. Started with the '46 BC-12D. New spars on the way.

    Yes, it will be hangared.

    Thanks all for the advice!! Happy to talk about the project.
     
  23. bluerooster

    bluerooster Pattern Altitude

    Joined:
    Nov 28, 2011
    Messages:
    1,883

    Display name:
    shorty
    Yep leave them bare. Just clean them up and apply a conversion coat. Tom mentioned Alodine, I prefer PPGs EAP 12, it's more environmentally friendly than alodine.
     
  24. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    I wonder if it is as good, there is a hazard when the Alodine is not removed.
     
  25. bluerooster

    bluerooster Pattern Altitude

    Joined:
    Nov 28, 2011
    Messages:
    1,883

    Display name:
    shorty
    It's actually better IMO. Having used both, I prefer EAP 12, or EAP 9.
     
  26. Bell206

    Bell206 Final Approach

    Joined:
    Oct 6, 2017
    Messages:
    5,247

    Display name:
    Bell206
    Is that a bluish, 2-part conversion coating system?
     
  27. bluerooster

    bluerooster Pattern Altitude

    Joined:
    Nov 28, 2011
    Messages:
    1,883

    Display name:
    shorty
    Yes, -12 is the purple stuff, -9 is clear.
     
  28. bluerooster

    bluerooster Pattern Altitude

    Joined:
    Nov 28, 2011
    Messages:
    1,883

    Display name:
    shorty
    I believe it to be as good as, if not better than alodine. And don't wash it off after application. Put it on, let it dry, and you're good to go.
     
  29. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Tell be again, why the new stuff needs to better, we had have Alidine (chromic acid)since WW2 and before and there has never a problem.
     
  30. Bell206

    Bell206 Final Approach

    Joined:
    Oct 6, 2017
    Messages:
    5,247

    Display name:
    Bell206
    FYI: Alodine/Bonderite is considered hazardous material and is regulated. The EAP-12 is not. Big difference on shipping/disposing of between the two. Down side is the shelf life of the EAP-12 once activated is short.
     
  31. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,736

    Display name:
    Tom-D
    Oh Hell yes,, Thank You California

    You may believe Alodine/Bonderite are the Same, they are not.. the product we used to get does not act the same of the stuff we now get, is way different.
     
  32. Bell206

    Bell206 Final Approach

    Joined:
    Oct 6, 2017
    Messages:
    5,247

    Display name:
    Bell206
    I don't believe that. But for the newer users here, I try to tie things in. Nothing today is the same as it was even in the 80s. It is what it is.;)
     
  33. bluerooster

    bluerooster Pattern Altitude

    Joined:
    Nov 28, 2011
    Messages:
    1,883

    Display name:
    shorty
    Not saying there has been a problem. But when a better less dangerous product comes out, why not use it? Alodine is not the same stuff today as it was years ago.
     
  34. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,407
    Location:
    Wasilla, AK

    Display name:
    stewartb
    I use Variprime on the assembled wings. No adhesion problems with Ceconite or Stits products, and the only place that matters is leading and trailing edges. Rib caps get rib stitched. My leading edges are extended back and the rib stitching goes through that metal. There’s no separation between ribs. I like Variprime on aluminum. Used it on an engine and top coated with gray Imron. That worked great, too.


    A28AB19F-7DFB-493B-A67A-B2A931AEE383.jpeg
     
  35. kyleb

    kyleb Final Approach PoA Supporter

    Joined:
    Jun 13, 2008
    Messages:
    6,521
    Location:
    Marietta, GA

    Display name:
    Drake the Outlaw
    How do you chafe protect the stitches where they go through the sheet aluminum?
     
  36. Stewartb

    Stewartb Final Approach

    Joined:
    Nov 21, 2014
    Messages:
    7,407
    Location:
    Wasilla, AK

    Display name:
    stewartb
    anti-chafe tape, just like with ribs. The stitch holes are located so that the stitching doesn't touch the drilled holes.

    B74DF564-AB89-4750-B678-7942CF24EFE8.jpeg