First look at the aileron

[mhorowit]

Re: First look at the aileron

We used scotchbrite pads to clean the aluminum in the Navy.
Then treated with alodine before we primed and painted.
That was 25 years ago though.

GOOGLING for 'alodine' I found an interesting article
here.

But it begs a question. It talks about the alodine process followed by priming and then painting. But the leading edge of my aileron seems to be unprimed and unpainted aluminum. Does this mean the aluminum was originally anodized and didn't need further treatment, but we're alodining which requires at least a priming coat? - Mike

[Winston L.]

Re: First look at the aileron

The original metal on the aileron was bare alclad. There are several manufacturers like Mooney that are alodining only.

Winston L.

[alwaysoar]

Re: First look at the aileron

Mike--I took both my ailerons completely apart and replaced the spars, a couple of ribs, etc., scrubbed the leading edges, welded new ends on the tip bows. I epoxied everything. It was a big job. IF you end up doing that, number each rib and its location on spars. If you do that then the old screw holes in the leading edges will line up saving a lot of aggravation drilling new ones and hoping you can hit the rib on the other side.

Ed

[Robert Lees]

Re: First look at the aileron

I'm coming into this discussion a bit late....

spar made of two pieces

Mine were in three laminations, Mike...although one had indeed split along a glue line:
I ended up replacing both spars. Have a good look.

dissimilar metals

That's what pigeon poo is for!

Look for any corrosion inside the leading edge on the aluminum

That's very difficult to do, Mike, without de-nailing the leading edge. Try with a fine torch (oops..flashlight) through the nose rib lightening holes.

If you are covering with stits I would use the epoxy primer

Also, the "new" Superseam is the same as the Stits product (MEK-based PolyTak), so the same precautions will apply. "Old" and "new" Superseam are not chemically compatible.





With reference to "Alodyning": that is the trademarked name of a particular chemical process (perhaps DuPont?). Stits has their own version called "Aluma-Dyne E-2300"...fundamentally both are a chemical process whereby the surface atoms are converted to a ceramic-like material which is very impervious to corrosion-promoting agents like oxygen. Alodyning is a two-part chemical mix; the Stits equivalent is single-part.

Unfortunately, this coating is thin and brittle, so is easily damaged by handling etc...my own suggestion is to either alodyne and then epoxy-prime, or etch-prime and then epoxy-prime.
Or better, do all three (which is what I did on all my aluminium).

Further, Anodising is an electro-chemical process. I don't know more...I'm not a chemist.

But be aware: all the above processes require an aluminium surface to work on, so all corrosion, dirt, grease, fingerprints, magic markers, lipstick etc needs to be removed before application. I used the Stits (sorry...Poly-Fiber) "Aluma-Dyne E-2310" acid-etch cleaner to perform this, using Mike's "stainless kitchen pads" and Scotchbrite (yet another tradename).

I won't go into the details of what I did to prevent future spar crushing at the bolt holes, because you probably can't do in the USA what I did here...all that info is available on my website.

As an aside, and only just off-topic, Winston's input to this group is very welcome; he seems to bring a wealth of knowledge which I'm sure is appreciated by everyone.

Rob

[mhorowit]

Is this masking tape?

Over isolated screw heads and along rows of screws is what appears to be a strip of masking tape; obviously providing a smoother surface for the fabric.

Is it simply masking tape or something less likely to retain moisture? - Mike

[Robert Lees]

Re: Is this masking tape?

Mike: Please don't use masking tape...it's paper-based and will retain moisture. All my screws had this stuff (probably from original manufacture) and these days it's poor practice. Also, the next person recovering in 30 years time, he'll be cursing your name forever.

I don't know about other than the Poly-Fibre process, but they use a cloth self-adhesive tape...I'm sure the other systems use similar. Don't use it in long strips...just in short patches; it won't show under the fabric too much, and in long strips, the long edges will curl up.

Think of banknotes...they are cotton-based (despite it being called "paper" money), and will survive going through the washing machine.

By the way, what Hex-head screws were you referring to earlier?


Rob

[mhorowit]

Re: Is this masking tape?

Mike: Please don't use masking tape...it's paper-based and will retain moisture. All my screws had this stuff (probably from original manufacture) and these days it's poor practice. Also, the next person recovering in 30 years time, he'll be cursing your name forever.

I don't know about other than the Poly-Fibre process, but they use a cloth self-adhesive tape...I'm sure the other systems use similar. Don't use it in long strips...just in short patches; it won't show under the fabric too much, and in long strips, the long edges will curl up.

Think of banknotes...they are cotton-based (despite it being called "paper" money), and will survive going through the washing machine.

By the way, what Hex-head screws were you referring to earlier?

Rob

Thanks for the tape info.
I'll clean up one of the screw heads and take a pic later today - Mike

[mhorowit]

Re: Is this masking tape?

Thanks for the tape info.
I'll clean up one of the screw heads and take a pic later today - Mike

Rob - here you go; 5/32" across the flats - Mike

[Hank Jarrett]

Re: First look at the aileron

I remember those screws all over mine! Pain in the backside to get out. Lots of heads snapped off abd others the screw slot stripped or the flats rounded. I found a really clean (not rounded or loose) small socket worked best. Soak it is penetrating oil or oil of wintergreen followed by silthe twisting gently back and forth with the socket to break it loose. Never broke one or striped it after that. Got to be REALLY patient!
Hank
Patience I got. Anybody that knows me knows I can take YEARS to do what others do in days!

[Hank Jarrett]

Re: First look at the aileron

We REALLY need spell checker here (or i need to proof before I press send!).
That's "Lots of heads snapped off AND others the screw slot stripped or the flats rounded" and "oil of wintergreen followed by SLIGHTLY twisting".
Guess I'm not patient with the "SEND" button!
Hank

[flybikefarm]

Re: First look at the aileron

If you put valve lap compound on your screw driver it helps stop the blade from slipping out of the slot. george

[dedrekon]

Re: First look at the aileron

Hank, I agree spel chekir would be a great benefit on this forum....it might keep some of us (like me) from sounding like they didn't lern thar siferin reel gud.
You CAN go back and edit any post you've made. Just go to the bottom of your post (you must be logged in), click the edit tab and voila, everything can be fixed.

V

[mhorowit]

Re: First look at the aileron

Make sure the doubler plates are still attached well. I have taken alot of them apart and found although the spar was still good, the glue joint has failed around doubler. If those are still good, repair revarnish, and go on.

Mike

There does seem to be a gap between the doubler and the spar. I"ll get my A&P's opinion on whether or not they need to be replaced.

My first thought is "why any glue; after all, the doubler is clamped in place", then I realized that without gluing, the doubler could warp or otherwise not act with the spar as a single piece (as I'm seeing with that gap(above). I think I've answered my question - at least with a logic I'm happy with - anyone care to add to this "theory of gluing"?

[jdoran]

Re: First look at the aileron

Mike,

You are getting a lot of good advice.

If you can't get a socket on a screw, and the slot is bad, you can use a hacksaw and cut a new slot in the head of the screw, but don't cut the slot too deep or the head will break off. Cut the slot only as deep as the original slot.

Also, if a screw head is sloppy in the socket, try using a metric socket. sometimes they will help get a better grip.

John

[crispy critter]

Re: First look at the aileron

A 6 point boxed end wrench works much better ,grind about 1/3 of the wrench away so it lays flat on the leading edge and grips much better