Having never worked with molten lead, I wanted to do this job before pouring lead for the keel. If you follow the manual you’ll do the big keel pour before the small centerboard. The manual points out that everything doesn’t have to be necessarily done in the exact order as it reads.
Working with lead wasn’t difficult but I am glad to have done this small job before the keel. I learned a few things that will be helpful for the big job.
- I now have the right tools. I started out with a soup ladle to skim my dross and wound up finding a spatula worked much better.
- I now have a feel for temperature and how it affects the lead. I melted two batches and my second batch was much hotter because I kept turning up the gas. I was unsure whether or not I was getting all the impurities out. The increased heat created a situation that, due to my inexperience, wasted a lot of my time and a little bit of lead. After skimming the dross, the surface of the lead in the pot would turn gold, purple and deep blue. The first batch was silver only. I thought these colors were impurities and kept skimming but the colored surface never dissipated. Finally I just went ahead and poured. Afterwards I googled and discovered that the colors were simply due to oxidation of the lead at high temperatures. So I skimmed off and threw away some lead for nothing. Lesson learned. And next time I won’t worry to get it so hot.
- I also have a feel for how much lead I can safely pour at once, which will help when I’m pouring numerous batches for the keel.
If you’ve never done this and are concerned, don’t be. Do the small centerboard pour first to get your feet wet.
A thought concerning the rabbet: The poured lead doesn’t level out and harden symmetrically. It gets lumpy. I’m assuming due to trapped air, uneven cooling, etc. Make sure you try to fill the rabbet with a single pour. I would imagine that the rabbet might not get completely filled otherwise, which could reduce the purchase area the ballast has on the centerboard. Can’t fathom the thing actually coming loose and falling out somehow but who knows.
Next for the centerboard is to cut a rabbet for the leading and trailing edges.