I just used the excessivly long zip tie (14") from scotch brand I believe since they're a bit wider than the smaller 8" and 6", these can be found at a local hardware store or Home Depot. They have at least a 50lb tensil strength. Also get a name brand, we get some free zip ties with some parts at an audio shop I work at, they break apart just zip tiing something together.
Edit: The 14" have a 75lb tensil strength.