I took a section of ½” galvanized pipe and chucked it in my lathe. I was testing 4 surface textures on the pipe.
Surface 1: Nothing done, left galvanized.
Surface 2: Scuffed down to 100 grit sand paper
Surface 3: Scuffed down to 400 grit sand paper
Surface 4: Polished to a mirror finish.
At first I dipped the pipe into water and removed it. I left it over night and checked it the next day. After 3 days It looked like nothing was happening.
I thought next to leave it submerged. I got zip lock bag, poured some water in, and dropped in the pipe. Three days later, nothing. I was surprised. I thought for sure this thing would rust.
Finally, I dropped a few other pieces of steel in to include a piece of galvanized wire, a section of 1” galvanized pipe, and a piece of 22 gage sheet metal. After another 3 days I emptied the bag and found out the following.
The galvanized pipe, regardless of removing the coating with any grit, did not rust. Though the pipe got a white cloudy residue on it. It appears the more the pipe was polished the less it got this cloudiness on it. This was same for both the 1” and ½” pipe.
The galvanized wire got the same cloudy coating on it. However, it rusted where there was no galvanized coating.
The 22 gage sheet metal rusted a lot. I thought about polishing a piece of it to a mirror finish and dropping it in water again but I figured this. Any piece of jewelry made with sheet metal, though most of it can be polished to a mirror finish, there will be some tiny areas that will not. So even the best polishing efforts wouldn’t make it water proof.
My conclusion is I'll be using more of the pipe from the electrical section of the hardware store.