Rick Meyer wrote: > Sounds basically a good plan, Mark. A couple notes for others: > 1. Take some care not to breathe the fumes when you play with > melting lead. I know that inhaled is much worse on the brain cells than > ingested (as from kids gnawing on windowsills painted with old > lead-based paint), and this sounds like it might qualify as "inhaled." > I melted lead like this long ago to cast a slug for a sailboat keel, and > that's been my excuse in the years since. We don't need a bunch of KR > pilots lowering their IQs. (Someone with medical expertise may > correct me, but I'm going to keep using this excuse anyway.)
I didn't inhale. Really! > 2. I doubt that pouring epoxy in the tube before pouring the molten > lead in would have held it. In your case, you could just stick a drift > punch to the lead after it has cooled, thump it once or twice with a > hammer, repeat at the other end. Expanding the lead like that to the > form tube it should grip tight. Or, use copper tubing for your form > tube -- the lead will bond to that. I did exactly that, and just in case, it's also epoxied now, and so doubt it's going anywhere. > 3. Thinwall 4130? I know one gets in the habit of using the > lightest material that will work, but this is the obvious case when > heavier is not bad. If you have that thinwall around and want to use > it, fine, but wouldn't a length of 1/2" iron pipe have had more texture > inside and out for bonding inside to lead or outside to carbon fiber? > Iron a bit less dense than lead, you might have needed a few more inches > total. 'Course, the iron pipe could rust, so . . . Thin wall because I had some laying around, and because the thinner the wall, the more room for lead, and therefore the more effective per unit length. Since my ailerons are rather short (larger moment arm) I only had a finite amount of length for them. There's no side load on this thing, so I'm not worried about it sliding out either, especially through the "healed" aileron end caps. Mark Langford, Huntsville, Alabama N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford
