I live in the rainy Northwest United States and have seen these nifty 4-gallon square bucket panniers on some bikes over the past few years. A new pre-assembled pair will set you back about 90 dollars. I knew I could build them cheaper. Plus, I get way more satisfaction out of DIY products. For around half the price I was able to make my own, using brand new buckets and hardware. With a little ingenuity, you could save more scratch, it's up to you.
Here is what we'll be building:
Step 1: Gather Your Ingredients
Here is a pictorial inventory of what you will be needing:
Step 2: Trim and Drill and Awl
In this Step, we trim portions of the bucket lips so that the pannier brackets will fit flush with the exterior wall of the bucket. Additionally, we poke a hole through the nylon webbing that will become the carry strap and the bungee retaining strap. Use brackets and washers for a good guide on placement of holes.
Step 3: Get Strapped
Here we assemble the hardware to the freshly awled straps.
Pictured below are the drilled/trimmed buckets, the assembled carry strap, and the assembled bungee retaining strap. Shock, aka Bungee, cord is inexpensive so I bought new at approximate 2' lengths. Overkill... better than underkill. Really we only need about 18-20 inches.
Use your best judgment for the measurement of the webbing straps.