4" Bokakob Column Packing Options

[roachmann]

Hi all, just looking to gauge some opinions here.

I've done plenty of reading on/searching for packing options for my upcoming 4" Bokakob build, and am faced with an unpleasant truth; either I must open my wallet wide, or I must get creative.

I'm looking around for some creative packing options that ideally aren't going to bankrupt me. Copper scrubbers are pretty expensive here, or at least the amount of them I'd need to fill a 4" tube to around 1500mm high makes them cost prohibitive. Glass marbles seem to be no one's first choice any more, and again are cost prohibitive. SPP would naturally be amazing, but I don't much feel like remortgaging the house just to pay for packing, and even raw material cost to make that volume of them is expensive, several hundred dollars for a spool of Stainless mig wire last time I checked. Ceramic staples/rings would be nice, but again, will cost several hundred dollars to get the volume I need.

Natural first thought would be Lava rock/scoria. I'm not sure if anyone else from New Zealand can chime in here, but all the rock I've been able to find here is a solid red colour, not the nice black rock I keep seeing photos of on here. The Red colouration is supposedly caused by iron oxide, which doesn't strike me as being particularly nice to pass your product through. Has anyone tried using red scoria before, and if so, what do you think of it?

Next option which comes to mind is Stainless Steel swarf. I'm a machinist by trade, so I have access to near unlimited volumes of what is essentially sharper than normal Stainless scrubbers. Naturally I'd need to clean it thoroughly, to remove cutting oil residue etc. I've tried searching to see if anyone has used it, the best I could find was people saying it might possibly work ok, but no accounts of it actually being used. Has anyone here tried it, or can anyone think of a reason why it wouldn't work? For the record, I'm talking about long stringy lathe swarf, not small chips. Although I've got plenty of those too!

Sorry for the long winded post, thanks in advance for any input you may have!