Well, I finally had a day off that wasn't a holiday, and brewed my first all grain batch: Jamil's Southern English Brown. Well it appears I'm missing a collet from the attachment of my new false bottom to the tubing that runs to the valve on the mash tun. Noted: a loose false bottom will let grain through and stick your mash.
I honestly thought the weight of the grist would push the dome down and create a seal. Not so much.
Another factor in the sticky sparge category may have been the crush. Thought I'd try my hand at the old hand crank cornmeal mill. From what my inexperienced eye could see there was a lot of free floating starch powder and a completely separate bunch of more or less intact barley husks. The best I could dial in, but probably way too inconsistent and way too much powdered barley.
Anyway, back to the open valve with nothing coming out of it:
I had a 3 gallon collander and a grain bag that fits around it, so I strained as much as I could through there, even did a "sparge" the same way with all that water I had heated up.
There was way too much grain material in the wort after that, but I figured 'fuck it, what am I gonna do, throw it away?'.
Everything proceeded normally from there, had a fine boil with no boilovers. It still smelled amazing. Whirlpooled a bit as it cooled and left a bit in the kettle, so the resulting beer ended up marginally clear. Got it in the fermenter before the sun went down.
Thanks to the BN for all the knowledge. Without a clear understanding of what it was I was *trying* to do, I would have been scratching my head a lot longer and potentially messed up the beer even further. Thanks all.
Toast

Sounds like you crushed your grain a little too much. If you can make out a sizeable amount of very fine starch powder, you are likely going to end up with a paste-like mash that prevents the wort from flowing through. Describing the degree to which you should crush is more of a visual thing, but you should be able to see the actual grains look fairly intact while in the grain bag. How many Liters of water per pound of grain did you use for your initial strike water? Maybe your water to grain ratio was disproportionate.

The water to grist ratio was 1.5 quarts/lb, which I thought good for a single infusion. I agree, though that the crush was probably too fine. It was pretty much half barley husk and half powder. It's amazing how much stuf just crumbles out of the husk even if you just break the kernel with your fingernail.
I have a new LHBS just down the road, so I plan on just bringing my grain in there and crushing it on their mill until I can afford a real mill.
The big thing is getting the false bottom to do its job though.

Toast

We usually add 1/2 lb of rice hulls per 5 gal all-grain batch, as a rule. Someone's probably going to say "don't do that", but we've never had a single problem.

Same here. I even consider not brewing at all if I don't have any rice hulls. I do crush my grain quite fine but the rice hulls always bail me out.

Wayne

I'd be toast without rice hulls because of the depth of my "lauter tun" which is a 55 gal chemical drum. The guy that put the system together said in his instructions to split the lauter/sparge into 2 parts as the mash will impact at the depth it comes to when this thing is full. With rice hulls it is not necessary to do that. Without rice hulls, or without sufficient rice hulls, a stuck mash is a certainty.

i haven't used my mash tun in the last 4 batches since the first 5 though it stuck EVERYTIME. i blame my stainless braid collapsing. that isn't your issue. crush is the first thing to check. you don't want tons of flour created. i notice my monster mill crushes a tad different based on how fast i run the drill...