safety wire - stainless, iconel etc.

[flyboy1963]

Did a few searches, and failed to find an answer; what is the difference between 'regular' stainless steel wire, iconel, oxidized iconel etc.
I've had wire in my toolkit that seems to break very easily, and other that was so soft I figure it must be an aluminum alloy. (once off the spool, pretty hard to identify it!)
....to safety properly, should you use the largest diameter that will fit?

 

[AME at Large]

inside engines....

That oxidized inconel and inconel safety wire is used inside the PT-6 engines I work on, it can take the high heat. Not fun to work with as it has a texture to it and does not slide as easily as stainless steel wire. It also breaks easier and is much more expensive than stainless.
A quick Google search reveals the following details about the finer points of safety wire;
Inconel is useable at 700 degrees F and above, hence the use in the hot section of the PT-6.
Monel is good up to 700 degrees F
Stainless has no temp rating.
(All from the GAHco catalog in case you were wondering)

For all applications on a RV I would use stainless steel as it's easier to work with. As for size the important place to use .041" is on primary flight controls and prop bolts. AC43.13 has a list of wire sizes for turnbuckles, it's table 7.8 in Ch. 7. While it says to use stainless for 1/8" cables and above I've lockwired 1/16" trim cables with .041" and it's like wrapping a coathanger around a pencil.
Most things on the engine are commonly wired with .032" (oil filter, drain plug etc.) Cannon plugs and other connectors I usually use .025".
If you use the largest size that will fit you may break the tabs that are supposed to hold the wire, a common problem on cannon plugs. Some places on engines are easily broken by using too large a wire and pulling a little too much. It's a bugger to try to wire something when the hole is broken out.
Hope this helps. Have fun lockwiring and as my instructor said "if your not bleeding when you are done, you're not doing it right!"
Phil

 

[GAHco]

Thanks for the Plug!

I appreciate your mentioning our reference book page.

Here is the link to that page to save onlookers some time.

http://www.gen-aircraft-hardware.com/images/pdf/ms20995.pdf

That Inconel is weird, it seems softer than the other stuff, and breaks easy compared to regular safety wire, but will stand up to more heat than any thing I am familiar with. Just interesting but there is no where an RV needs it.

Maybe for the prototype RV20 with a small turbine engine.
Jus-kiddin

 

[john.schwaner]

Monel safety wire is used:
1. In explosive areas as it is non-sparking i.e. Boeing-767 AD-2006-08-04
2. In high-vibration areas, such as the Titan II because of its high-fatigue strength
3. High-temperature areas. Monel 400 melts at 2,600 degrees F
4. Resists breakage and is re-usable - securing fishing nets
5. Easier to work with your hands.

give it a try - you might like it over traditional stainless steel wire