Likes: What do you guys do before covering you controls surfaces? Primer, paint or just leave it as it is. Thanks guys about to cover a set of flaps I just built .
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What do you guys do before covering you controls surfaces? Primer, paint or just leave it as it is. Thanks guys about to cover a set of flaps I just built .
Good epoxy primer and I tend to use a topcoat too...but some epoxy primers are also a sealer too...in that case you don't need to paint.
If you're talking ailerons I don't paint them. Just the short piece of steel tubing on the trailing edge.
I just cover them....
but since you are by saltwater(Seldovia?).. then you might prime them...(use a good 2 part epoxy primer)
I have been thinking that you would need to epoxy prime any area where you use glue to attach fabric. Ceconite and Poly-Fiber require this on new metal… other covering systems may require priming of these areas also.
What is the consensus about this?
I like to prime and top coat steel parts.
Wasn't aware of any requirement to top coat aluminum prior to covering. After treating the surface corrosion on the aluminum parts of my Clipper wings I epoxy primed them. I don't usually prime new aluminum parts unless the customer requests it. I have found lots of corroded aluminum when uncovering over the years. The steel definitely needs attention. I blast, epoxy prime and top coat with catalyzed polyurethane. Here is a thread with some sobering pictures.
http://www.shortwingpipers.org/forum...n-thread/page2
Steve Pierce
Everybody is ignorant, only on different subjects.
Will RogersGoodolboy liked this post
Source?Originally Posted by Jasperfield
Remember, These are the Good old Days!
Poly-Fiber Procedure Manual No. 1. Revision 21, September 2006: Ch. 2 - Airframe Preparation: New Aluminum. page 11.
Ceconite Procedure Manual 101, June 2008 Revision, Ch. 2 - Airframe Preparation: New Aluminum, pages 10-11.
Star Gloss Procedure Manual, May 2010, Ch. 2 Airframe Preparation: New Aluminum, page 8.
For all applications of glue, on new aluminum, the respective STCs require: Cleaning of the new aluminum; one of the following as specified: conversion coating wash or Alodine wash; and application of Epoxy Primer.
Wow, looks like I gotta do some reading.
Thank you everybody, this is a great place to go for help. I'll primer and paint everything. Easier than redoing thing a few years down the road.
You and me both Steve...
Revision 21: Page 11 of the Polyfiber manual says under 2. Airframe Preparation, New Aluminum, "Prime with epoxy primer. See directions in the paragraph above on Old Aluminum."
Under Old Aluminum it says: "Old aluminum must now be acid etched, treated with a conversion coating and then primed for best results."
I guess it is open to interpretation. I think epoxy priming is good but have removed most all systems from lots of airplanes I have yet to see a problem with the fabric adhering. I have seen isolated incidents of corrosion.
I agree that this is definately open to interpretation and I can't see anyone getting into hot water for covering over bare aluminum if they so choose.
In my opinion the Revision 21 manual was developed to guide inexperienced people through the process of restoring an airframe prior to covering. Their manual uses several "non-binding words on page 11 and elsewhere such as "primed for best results" and "We recommend using EP-420 white epoxy primer over aluminum." They do a good job of guiding people from using products that will cause problems, but the STC is only for the installation / use of Polyfiber fabric on the airframe.
The STC is not the final authority in how the airframe preparation is done. There are plenty of other guiding FAA and manufactures documents for that.
Polyfiber Epoxy primer is a very good product and should be considered a "best practice" in most cases, but I don't see where they can mandate it to be used over all aluminum surfaces.
Their manual also treats the preparation of steel tubing in a similar manner by referencing only the use of Epoxy primer. If this is a literal mandate for surface preparation then they have just outlawed the usage of Powder coated steel structures, (unless you want to prime over it).
How many people do that?
Ed
They can do anything the feds approve, but that does not mean older STCs are revoked. Just keep on using your older procedure manual.
Opinion.
Also the opinion of my FSDO last time I checked, which was a while ago.
My experience is that a well cared - for Cub wing or aileron will show no corrosion, even if parked outside, so long as it is flown regularly. Let continuous moisture in there, and you can have a pile of gray powder. Mine got shot with a haze coat of zinc chromate in 1969, but I have seen others that were bare in good shape.
My PA11 EX project is primed with Macropoxy. It is a marine epoxy from sherwin williams. I think it is a sealer as well by looking at the applications....anybody ever use this stuff? or g=have experience. I was thinking of top coating, but I don't think it's necessary.
http://protective.sherwin-williams.c...3Aproduct-6841
The worst examples of aluminum corrosion under fabric I've seen were under the Blue River process. However this is ancient history.
Back to the original question: Where is your Cub going to spend the next 25+ years? In what environment, doing what sort of operations?
If the answer is "I don't know." then I'd suggest corrosion proofing is a great idea. Maybe the next owner will put the thing on floats, and operate it in the bayous of LA.
Do do him or her (and yourself) a favor and treat that metal for worst case use.
MTV
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