Apw99
Yes PVA, old emulsion paint, wax, even clingfilm will do it, think of the grain being like porous drinking straws, stop up the ends and it will dry evenly through the sides so doesn't have the inclination to split. If you can't go out then find something you already own to block up those straws!
dis-organised is good, an organised turner is a dangerous thing! drying time is quite variable to air dry a plank the book says about 1 year per inch thickness. But with good airflow warmer room etc. that can change drastically. Best way to see if wood is dry is to weigh it regularly when the weight stays the same then it is dry, BUT you do not always want dry wood, turn the walls of a bowl to even thickness and you can turn it pretty wet, especially with cherry.
I get a lot of wet wood, if it is new to me I will tend to turn it in 3 phases one about a month after getting it, one about 3 months, and one a year or more down the line first one is probably going onto the fire, but I will at least know from that if the wood is worth drying, and as long as you clean up the wet spots from your lathe etc. it can be a lot of fun to turn it wet! 3 months as long as I have prepped it to approximately 1" wall thickness will often be a usable turning, but will also inform me if I want to wait longer.
Lumpy danish (or any oil) is usually because of air leak and is usually the tung oil component that solidifies any oil that is made of multiple ingredients needs a good shake to mix it up every now and then, and also doesn't want much air in the tin, I have never found it a problem possibly because it is never hot for long here, but have seen people putting marbles in the tin as they use the oil to keep the air inside to a minimum.
Sanding Sealer is usually used under wax finish, it gives a non or less porous coat to the timber, it should never be used under oil which is designed to soak into the wood. It can also be handy for stiffening up small end grain fibres allowing easier fine sanding of those area's but they have to be pretty much sanded to 300 grit level first. Sanding is an art form in itself, always work through the grit levels never skip one, I start carefully with 120, (some who see my work think I need to start with 40!), I say carefully as 120 will destroy detail as quick as a slipped skew. Then 180 / 240 / 300 etc depending on what I am making it may stop there, or go on to 2000+ if I am using sanding sealer then that would normally go on after the 600 grit, if I am using oil then I may wet sand with oil on 600 grit it really depends on the wood, the cut, e.g. bowl or pen, and a hell of a lot on my mood at the time!