I just completed a pair of homemade aluminum trekking poles. My goal was to make them light weight and cheap. I followed the instructions in Ryan Jordan's article titled "Make Your Own Trekking Poles"
The poles weigh 3.4 oz each according to my local post office scale.
The total cost was $44.
The trekking poles were made from .380" Easton aluminum tent poles that I purchased from TentPole Technologies, LLC (www.polesforyou.com). I ordered four 26" pole sections (two of them with inserts so that they could be attached). The cost was $26.
I purchased the EVA foam grips for about $4 from ebay.
For the tips I used Leki carbide replacement tips ($14 from local shop).
The pole sections were attached with JB weld and then cut to length.
The tips were attached with 2 ton epoxy.
The grips were drilled out to fit tightly over the top of the poles.
As mentioned in the article, the disadvantage of using the aluminum tent poles is that they will not be as rigid as carbon poles. I plan to try them out on a rim to rim to rim hike in the Grand Canyon at the end of the month.