jsharkey

jsharkey

Well Known Member
What is the correct process for applying waxy lacing thread to wiring bundles? Three wraps and a reef knot seems to work.

Also can it be used Fire Wall Forward?

Jim Sharkey
RV6 - Wiring
 
I'd have to dig it out, but I seem to remember aeroelectric.com had a document on how to tie these. You might also check AC 43.13B. It's basically a hitch with an overhand.

Here's Bob's link: http://aeroelectric.com/articles/cable_lace/cable_lace.html. I used Method 2 almost exclusively and it works well.

I also scoured 43.13B and couldn't find a reference that said NOT to use FWF. There were references against using zip ties, but not ties.
 
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Jim P said:
I'd have to dig it out, but I seem to remember aeroelectric.com had a document on how to tie these. You might also check AC 43.13B. It's basically a hitch with an overhand.

Here's Bob's link: http://aeroelectric.com/articles/cable_lace/cable_lace.html. I used Method 2 almost exclusively and it works well.

I also scoured 43.13B and couldn't find a reference that said NOT to use FWF. There were references against using zip ties, but not ties.
Click to expand...


I used Bob's Method #1. It is right out of AC 43.13B. I have them forward of my firewall. They have held up well for the past 10+ years and 2,084 flying hours.

A little tip that I use with the WAXED lacing, after Bob's method one is completed with a square knot, I hit it with a heat gun to melt the wax and help hold the knot together.

I like the waxed best. I know others that do not like the waxed because they say it attracts more dirt. I have not noticed more dirt on my installation over the past 10+ years.

Remember that my advice may only be worth what you paid for it.
 
I used the AC43.13 method which is a clove hitch secured with a square knot (same as Bob's method #1). Description of lacing and ties starts in part 11-158, the single tie is shown in figure 11-17. With a little practice it becomes quick and easy. I found the easiest way to REMOVE the tie (to add wires, reposition, etc) is to use flush cutters, perpendicular to the wires, to cut the knot off.

I used lacing tape everywhere, including under the cowl, and would do so again.

Hope this helps-
Jim
 
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Method number 3 is a poor choice even if it does look good to the judges. If you have to cut one loop the whole darn thing comes undone. This method was used quite often back in the days of tubes(valves). I have been using method 1 and 2 now for more years than I can remember.
 
Some "how-tos"

Some reference documents....

I think this is an FAA document, but comes courtesy of Australia...

http://casa.gov.au/rules/1998casr/021/021c99s2c08.pdf

...and for the real historians.. a link to a 1962 (but probably created in the 50's) US Navy "Workmanship and Design Practices for Electronic Equipment" harnessing document.

http://www.dairiki.org/hammond/cable-lacing-howto/

The "noose" type ends are no longer used, but this shows how harnesses can be laid out on a sheet of plywood and assembled.

fig7-09.1.gif


It does look neater than ty-raps, and is quite easy to do after a little practise...

...and lastly, of course, the high-end NASA-acceptable tie knot...

401-16.gif


Spot ties shall consist of a clove hitch, followed by a
square or other similar non-slip knot (i.e.: surgeon, etc.).



gil A
 
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az_gila said:
...and lastly, of course, the high-end NASA-acceptable tie knot...

401-16.gif


Spot ties shall consist of a clove hitch, followed by a
square or other similar non-slip knot (i.e.: surgeon, etc.).

gil A
Click to expand...

I, of course, use the NASA-approved method....;)
 
Jim P said:
I also scoured 43.13B and couldn't find a reference that said NOT to use FWF. There were references against using zip ties, but not ties.
Click to expand...
Jim-
Were these 43.13 references just for using zip ties on FWF wire bundles or on wire bundles period? I'm assuming the former? Thanks.
 
Steve, it was FWF.

Take a look at 43.13-1B, Chapter 11, Section 12, which outlines use of lacing and zip ties.
 
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Mil Spec translations

If you see any lacing cord advertised, here is the Mil-Spec translation into English...

A typical reference

MIL-T-43435B, Type I, Finish B, Size 3

Common options

Type I = Nylon
Type II = Polyester

Finish A = natural
Finish B = waxed

Size 1 = 0.200 wide
Size 2 = 0.110 wide
Size 3 = 0.085 wide

Sizes 4 and 5 are too narrow for our use....

Rolls of these tapes often turn up in local surplus stores if you are in a city that has much electronics work...
It seems most lacing tapes are made to the Mil-Spec, even if the Mil-Spec is not needed for non-critical commercial use.

gil A
 
How to make a lacing knot.

I lace most of my wire, and was interested in this thread, to see what knots people used. Looking through I found it very difficult to understand how the various knots were made. That set me thinking that unless I had been taught by a live human I would still be using plastic ties which I think are far inferior. So, in case anyone is interested, I have tried to make a photo sequence as to how to make the knot I use, in case it is of use to somone else. It is a great knot that I was taught in a w'shop at Sun 'n Fun a few years back.


See http://gikonothr.blogspot.com/2008/03/lacing-knot.html#links

I dont have a name or know if it is NASA approved! I have only ever made it with waxed thread.
 
jsharkey said:
What is the correct process for applying waxy lacing thread to wiring bundles?.....Jim Sharkey RV6 - Wiring
Click to expand...
I have always preferred string ties/lacing cord...whatever you want to call it over zipties/tie wraps whatever you want to call them. Taking a cue from my production days, the electricans routinely tied wire bundles together every few inches along their unsupported run by securing the bundle using a clove hitch followed by a square knot. The tails were snipped close to the knot and that was that. Years later when I was ready to build, I reviewed a few on-line animations to understand exactly how to make a clove hitch.

http://www.apparent-wind.com/knots/clove-hitch/

With little practice, it becomes very easy and I'm sure you will find that you can tie such knots with abandon and remove them just as easily when an unanticipated wire or wires are later added to the bundle. Light, cheap, and simple, it is a better option than zipties but I don't think the waxy material is suited for firewall forward applications.

​
 
Why are zip ties so bad?

Looking at photos of laced wires makes my wrists and fingers hurt just thinking about it. I'm old enough that when I started my mechanical engineering career some of the electronics types I was dealing with still secured wires using lacing, and I was taught various techniques for doing so. Having been diagnosed with both carpal and ulnar tunnel syndrome in both wrists, the repetitive motions necessary for something as simple as lacing, while a non-issue for most people, eventually give me fits. Still, if lacing is that superior to nylon zip ties, I'll find a way.

And yes, I will eventually get surgery (my friend the orthopedic surgeon grins and wrings his hands every time he sees me), and yes, it impedes the progress of the rest of the project, but I'm getting there.
 
Knots and temperatures....

Rick6a said:
...... Years later when I was ready to build, I reviewed a few on-line animations to understand exactly how to make a clove hitch.
......
Light, cheap, and simple, it is a better option than zipties but I don't think the waxy material is suited for firewall forward applications.
Click to expand...

Rick was obviously not a Boy Scout... a good place to learn knot making in your youth...:)

But, about FWF.... the Polyester (sometimes called Dacron) waxed cord has a temperature rating to 138 degrees C.

Since our MIL-W-22759/16 wire has a tefzel insulation with a 150 degree C rating, it seems to me that there would not be much problem with the use of Polyester (Type II) lacing cord in the engine compartment.

The Nylon tape has a little lower temperature rating at 121 degrees C.

The use description for Nylon says....

Flat braided hi-tenacity Nylon fiber impregnated with (MW)
microcystalline fungicidal wax. Engineered to stay flat. Distributes
stress evenly over a wide area. Resistant to fungus, flame,
abrasion and acids. Will not cut or damage insulation. Has strength,
toughness and stability.

I personally would use either FWF to keep small bundles of wires together....
Just don't tie it to a cylinder head...:)

One tying note...

The tape should be kept as flat as possible when being tied. The flat nature of the tape prevents a sharp edge from "biting into" the insulation over time. This is actually much easier to do than it sounds... the tape is flat off the roll, and does not tend to twist up as it's used...

gil A
 
All of the posts here contain great info. Wish I had seen the photos and videos of "how to tie" a long time ago when I was first learning. Knots are just not my forte. But I perservered and learned to do the knots and have since used lacing extensively, both in my own airplane as well as others that I have maintained, including turbine helicopters. When I have an option I always choose lacing over zip ties.

One note to those who are using lacing... I've found it easier when lacing a long bundle to spend a few minutes outside the airplane cutting off lengths of lacing. I generally make a heap of as many lace lengths as I expect to need then lay them out on a cloth. This makes the tying go much faster. Just grab a piece of lace, tie the knot, and move on. Once all are tied I go back and trim off the excess lace. Works like a charm, is light, and lasts forever. Heck, I still use some of the old round lacing cord and it works just fine too and has been around since, well, a long, long time... ;)
 
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