A co-worker asked me, why not just buy some fenders? And he has a point, but where's the fun in that? And, perhaps, the DIY project can be better in some respects than something off the shelf. Plus, saving 20-30 dollars isn't a bad thing.
I'd posted some waste-basket blade fenders earlier, and while they do mount in seconds and were ok for light drizzle and puddles they just didn't cut it for the real slop. So I decided to try some full fenders. I think they turned out pretty well. Bear in mind that the philosophy is to take whatever is easily available - and cheap - and adapt it without special tools. Or skills.



I used a six foot aluminum carpet trim strip from Home Depot, 1 3/8", about 8-10$. Other parts, a thin steel rod, two 8mm bolts with washers, a few inches of aquarium air hose, and zip ties.
Some hints in case anyone actually wants to make their own. Get it curved the way you want it first, and tied in, before working with the steel mounting rod. Bend one end in a circle and bolt that on, eyeball and bend the rod with pliers around the fender, and only lastly bend the other end around the other mounting bolt. Make one or both an oval to leave room for adjustment. The aquarium tubing is to slide on the bar, between the bar and fender so that it doesn't rattle.