From what I'm reading, it doesn't matter what kind of sawdust or shavings you use. Is that correct?

Pretty much.  It has to be DRY, you don't want to risk adding wet sawdust or shavings and getting a visit from the tinsel fairies.

I stick with sawdust from poplar/pine/oak/cherry (but those are the woods I cut the most).  Sticking with the lighter-colored woods makes it easier for me to see if I'm getting woods that I know will mess up my sinuses.  But they all work. 

YMMV, of course.

The best advice given here is to FLUX,FLUX and FLUX again. Most any carbon based item will flux your lead pot. Bees wax is very expensive, canning wax is too. I use the wood shavings from my planer. You could use wood chips sold as bedding material for snakes etc or chicken nest lining. The trick is to flux often and stir the pot while fluxing. Skim the ash and you should have a sliver mirror surface on the old lead pot. Good luck with your casting adventures.

doggoner

I see him on FB every day or so?haven?t heard anything from the Beav?

A few questions for you experienced LRB casters...

Do you cast with "pure lead?

It depends on what I'm shooting.  Most of the time--in revolvers, rifled handguns, and rifles--I cast from Rotometal's pure lead, or large lots of scrap that yields the same weights-for-size and hardness (tested 2 weeks after casting, as some alloys "age-harden"). A couple trips ago back to the old place, I finally remembered to pick up a couple of ingots.  Cuts with a thumbnail, weights for a .535 ball are within .1gr of Rotometal's pure lead, and hardness after 2 weeks is the same as Rotometal.  I'm calling it close enough to pure lead for my purposes.  Only problem is the ingots weight just a hair over 200#, and were a bit of a pain to hoist into the back of my 4x4. 

I usually use a harder alloy in smoothbores--I'll come back to that. 

Do you cast with a bottom pour or a dipper?

Most of the time, bottom pour.  With some moulds I use a dipper.  I have 4-5 dippers.  The Lyman's have the pour holes bored to different diameters.  When I use a ladle I typically do the "inset spout into sprue hole, invert so ladle is one top" method, and larger holes put more lead in the mould faster.   With larger moulds (like my brass .600) the ladle with a larger hole results in greater weight consistency and fewer visual flaws. 

Do you flux it?
What do you use for flux?

Do you stir it in and skim from the surface?

I flux when I add lead; if I'm casting small stuff or using a single cavity mould (so the pot doesn't empty as quickly), I flux every 20-25 minutes.  I use a heaping tablespoon of my Super-Secret-Recipe flux (i.e., whatever sawdust has accumulated in the bottom of my bandsaw since the last time I cleaned it out).  I dump it on top, wait a minute or so for the heat to drive off any residual moisture, then stir it into the lead using a stainless-steel tablespoon (never use your casting ladle to flux).  I scrape the sides and bottom of the pot, and stir in as much air as I can.  Then I use the tablespoon to gather up the dross from the top of the pot and dump it in my scrap can. 

If you bottom pour, is it really necessary to flux, mix and skim?

Only if you want consistent castings.  Once the mould and lead are up to temp, inclusions (dross, contaminants, etc) are major contributors to weight variations. 

I am trying to get as pure a lead ball as possible. I suspect that impurities in the lead pot affect the weight and accuracy of the ball.

Let's go back to the lead I use in smoothbores to discuss this.  Back when I was seriously shooting smoothbore pistols (I had some bizarre idea of trying to compete on the international level), I learned that casting from various alloys (vs nominally "pure" lead) resulted in different diameters as well as different weights.  If pure lead cast out at .650", a harder alloy might cast at .6525", for example.   

My source for most of those alloys was Ye Olde Scrap Yard.  I learned that if I didn't flux enough, the end product would have a consistent diameter but weights might vary as much as 2%.  So I fluxed, and still flux, (because after all how often are we working with metal that isn't at least surface oxidized?).