Conduit or Grommets

What are people's thoughts on conduit or grommets (and wax string/zip-ties) for wing wiring? And what are the best sources for things like good grommets or wax string (or bigger-than-van's conduit)?

Wax string.

I am going with wax string on my aircraft. Basing this on what I have seen at work ( I work on Army helicopters), the zip ties after a few years become brittle. Not to mention it would be harder to get them through the conduit. And it just looks better. Just my personal preference.

I have used both grommets and conduits, depending on accessibility. If you don't have access later, like in the wing, use a conduit. Otherthan that, the grommets weigh less. If you have a local electronics outlet in your city, they should have about any size grommet you could ever need. The outlet I go to has exactly the same grommets that VAN's sells, but in sizes ranging from about 1/4 in to over 2 in in diameter. You'll also probably find lots of other cool items you can use.

Wax string

Where would a person purchase wax string for this use?

Wicks (http://www.wicksaircraft.com/catalog/product_cat.php/subid=2051/index.html),
AIrcraft Spruce ( http://www.aircraftspruce.com/catalog/elpages/lacing.php )

There are many other electronics outlets that also sell it.

One roll can do...oh, about all of the RVs currently under construction!!

I'll second the wax string, While I don't work on anything that flies for my job I do deal with large A/V installations. Cable ties are the worst. Even inside, in the dark, in a temperture controlled building they will get brittle and fall off if moved. I'd rather not know how much blood I have lost to the things over the years either. If they are not cut just right they will rip the back of your hand right open. On another note while in a training class we were told that if they were overtightend they could cause a short, in cat 5, some balanced audio lines and can mess up dialectric in coaxial cable. (Thats mainly with the special guns though I guess.) Around here I try to use Heat shrink or techflex.

Jeff

Dental Floss

Has anyone tried using waxed dental floss? Try breaking some. You will be surprised.

1911pilot said:

I'll second the wax string, While I don't work on anything that flies for my job I do deal with large A/V installations. Cable ties are the worst. Even inside, in the dark, in a temperture controlled building they will get brittle and fall off if moved. I'd rather not know how much blood I have lost to the things over the years either. If they are not cut just right they will rip the back of your hand right open. On another note while in a training class we were told that if they were overtightend they could cause a short, in cat 5, some balanced audio lines and can mess up dialectric in coaxial cable. (Thats mainly with the special guns though I guess.) Around here I try to use Heat shrink or techflex.

Jeff

Click to expand...

Not trying to discredit you but I would have to disagree with you there. I am an avionics engineer by trade with a fair bit of experience doing installations (currently halfway through an extensive EGPWS, TCAS, Multiple radio and engine trend monitoring install on out 6th PC-12). We use cable ties wherever we can. We have found that wax string tends to undo over time unless you use the continuous tie technique and is in general much less reliable than cable ties (not to mention dificult to tie properly in restricted access areas). You say that they become brittle. I'm not sure what ties you are using but the ones we are currently removing from the PC-12 are 10 years old and are like new. We do use high temp cable ties in the engine bay though.
The only place I would use wax string in in a conduit.
As far as the grommet / conduit argument.
IMO I would use a conduit in a place where I had no access. Everywhere else I would use grommets.
Basically you could use grommets or conduit for a particular application and ties or string and it would not really matter. It all just comes down to personal preferance.
Good luck.