I will have to try the tobacco and the soda ash. If Min doesn't respond to this thread I will PM.
I did try letting the sheen go off of the base slip before I put the stained vinegar on it. Absolutely nothing happens when I do that. I don't even have a little fragment dendrites around the edge of my blobs. In the Robin Hopper Video, it looks like the base slip is very wet.
I haven't got around to adding vacuum to my antique bluebird. I picked up a new vacuum pump on craigslist for $40. Though I understand the rationale for shoving clay through the screen, I'm not convinced that it cannot induce as many air bubbles as it allows the vacuum pump to suck out. it seems is to me as if the blades do a pretty good job of slicing up the clay. I would think that would give the vacuum pretty good access to air bubbles.However, I've never seen a De-airing pugmill that does not have one of the screens. .... I would like other people's thoughts on this theory.
At this point, I think I'm just going to build a small clay trap with some pipe fittings and screw that into a threaded whole in the auger tube.,