On days when I don’t have the time to drive to dive sites in Monterey or Sonoma, or on occasions when I feel the need to trap dungeness crab. I sometimes dive at a site close to San Francisco, the crabbing is good when its in season and the diving is worse than mediocre. However, there is one thing I can always find in quantity when diving at this spot, lead fishing sinkers. The underwater structure is awful and although I have had terrible luck hunting fish it seems everyday that fisherman casting from the jetty snag their fishing weights along the rocky seafloor and the weights break free. When I go crabbing for the day I will drop my traps in the sandy area where the dungies like to be and then paddle my way over to the area where the fisherman lose their sinkers. In only a few hours of freediving and collecting handful after handful of abandoned fishing sinkers I can load my kayak with well over 100 pounds of discarded lead. Once I decide my kayak can’t handle anymore I make my way back to my traps and collect my crabs before heading in. The visibility is usually terrible, 2-3 feet, and the swell can be quite forcible, but at the end of the day I come home with a bucket of lead, at least a few dungeness crab, and I have gotten in some good freediving practice.
When I get home and after I have cleaned my dive gear and put away my crabbing equipment I set about smelting my lead and casting dive weights to be sold on Craigslist. The items needed to do this are fairly basic they are a dutch oven, a propane burner, a stainless steel spatula, a stainless steel ladle, weight molds, welding leathers or thick burn resistant clothing, face protection, welding gloves, some rags and a bucket of water.
Lets be clear about some of the safety hazards at risk here. Molten lead is about 600 degrees Fahrenheit, it will scar you badly, face protection is a must. The fumes from smelting lead are bad, don’t breathe them and don’t smelt lead indoors. Finally the most important thing you can do to prevent molten lead from splattering in all directions is to be careful to make sure your utensils are dry when you dip them into the molten metal.
Here is how it works, I place the dutch oven on the burner and fill it with lead sinkers. I ignite the burner and leave it to heat up for about 20-30 minutes. When I come back, the molten lead has sunk to the bottom and the calcified crust of the old sinkers is left floating on top. With all my protective gear in place I use a DRY spatula to scrape off the crust of impurities. I place the crud on a board or on the dirt and allow it to cool before I throw it away. With my weight molds and my water bucket handy I take a DRY ladle and scoop out 4-5 pounds of molten lead. Quickly I pour the entirety of the ladle into a DRY weight mold. It is important the weight be cast in a single pour, the molten metal cools quickly and for a solid lead weight it must be done in a single fluid pour. Once poured I fill up a few more weight molds, this goes much quicker with a couple extra molds, and I allow them to cool for a few minutes before plunging the molds into the bucket of water. I take the molds out of the water and strike each mold a few times against a brick to free my shiny new dive weights. At this point I use a rag and thoroughly dry the weight molds. I take the lid off my dutch oven and I scrape off the thin layer of black crud that forms when the molten lead reacts with the air. I then repeat the process and pour more weights until I’m out of molten lead. I don’t have a great method for measuring out exact weights, I mostly just eyeball a mark on the mold. When I’m done I use a kitchen scale to measure the weights down to the tenth of an ounce. The entire process takes a little over an hour.
I enjoy freediving, even in murky conditions for scrap. I feel good about removing lead from the ocean. When I post the weights on craigslist or bring them to dive events I have little problem selling the weights for 2$ per pound. Its nice to think that in a half day on the coast near San Francisco I can come home with several dinners worth of prized dungeness crab and a few hundred dollars worth of scrap metal.