[bach33089]

Okay, I do NOT want to open the can of worms that is the priming subject in this forum, but at the same time I have a very pointed question / request for advice, so at the risk of being stoned, here it is:

Has anyone used / does anyone have any thoughtful ideas on the use of Linseed oil (or more modern Corrosion X) to prevent corrosion INSIDE the control push rods? I have a lot of experience with Rag and Tube airplanes and this is the WORLD STANDARD for corrosion prevention in tubular aircraft construction, but is it a good idea in this application (leak out of rivet holes? seal them with RTV?) I am torn, but I don't think pouring primer down the thread hole is a good option either...

Thanks for the help!

 

[Bob Kuykendall]

Okay, I do NOT want to open the can of worms that is the priming subject in this forum, but at the same time I have a very pointed question / request for advice, so at the risk of being stoned, here it is...

Hey, what day is it?

Edit add:

First, a nitpick: I think it's pretty standard to call something a pushrod only if it's made from a solid rod. Everything else gets called a "push-pull tube." At least that's the way the rules seem to work.

That said, I wouldn't bother. The aluminum tubes are probably 6061, which is pretty corrosion-resistant from the start, and are probably anodized as well. I've picked apart a bunch of crashed gliders and airplanes, and none of them have shown any significant sign of internal corrosion in either steel or aluminum push-pull tubes. Besides, as you note the oil will eventually find its way out and make a mess inside the airplane.

Thanks, Bob K.

 

[fehdxl]

I had similar thoughts, but came to realize the tube in 'rag and tube' is steel which oxidizes (rusts) much more quickly than the aluminum push tubes. Plus, I don't think you could seal up the rivet holes and rod-end bearings for the long-term. Steel tubing is welded air/oil tight.

As a data-point, I ended up priming the inside of the push tubes and haven't given it another thought.

-Jim
40603, fuselage

 

[Mel]

That said, I wouldn't bother. The aluminum tubes are probably 6061, which is pretty corrosion-resistant from the start, and are probably anodized as well.

The aluminum pushrods in the RV kits are not anodized, but they are 6061, which as you say, is very corrosion resistant.
Many of the aircraft kits coming from Canada, such as those by Murphy and Zenair are built entirely of 6061, and most people don't bother with priming.

 

[terrye]

Push/Pull Tube Priming

I used Dinitrol AV8 inside all my push/pull tubes, especially the longitudinal aileron one which is steel. Powder coated outside, bare steel inside. Also epoxied the ends in the tubes as well as riveting. Yeah, I know, it's going to last 100 years.

 

[bach33089]

Thanks!

Thanks for the immediate advice, that is why I love this forum, no delay on answers! I should state that I am a rather young builder and this build is one I plan to keep for quite some time, that fact plus living in Florida has me paying a little closer attention to corrosion protection! Right now I am thinking about just following the priming suggested in the plans, it should be sufficient as the push rod is rather protected from the elements by the fuselage.

 

[aturner]

I used acf-50 inside my push-pull tubes, and yes, it does leak out the rivet holes and make a mess. But, I still like this method of corrosion prevention, and would probably do it again. A little ACF-50 goes a long ways.