Plain cast:
GSW 6" made in canada sometime in the late 1800's earl 1900's? Found it in an old cabin and replaced the burned off wooden handle with a turned piece of avocado wood. Really nice little pan.
A 6" Griswold and a 10 1/2" griswold fry pans. Both of these are really nice but have metal handles which is good for oven, bad for hands
A lodge 10" fry pan and a ?" turkey frier. The turkey frier is fine for its use, the fry pan has these circles ground in the bottom and is really rough, never did like it
A old Canadian made dutch oven (in the garage, can't remember make), really nice piece though.
The older cast is generally smoother. If I'm looking at used iron, I'm feeling it and seeing how smooth it is. If its rough its just hard to get it to not stick no matter how well you season it. Its also often lighter/thinner so its more reactive to heat.
There is a lot of
on seasoning, enough to drive you
if you try to figure it all out.
The short version is that you need to put down really thin oil coats and get them hot enough long enough to polymerize. Its just like using oil to build finish on wood. It takes a LOT of coats, they all have to be REALLY THIN and they need to FULLY CURE before adding the next coat. I've had good luck with Crisco, the Linseed oil method, Lard, etc... as long as I followed the above guidelines. The worst mistake most folks make is to put a thick layer of oil on and then cook the pan which then cures into a gelatinous mass that does no good at all. Having the pan hot when you spread on the grease helps with the thin layer. Don't get it so hot that all of the oil cooks off (hot enough to smoke a little is ok, especially on the earlier coats as it will lay down a bit of carbon which is harder than the oil polymers).
Food nerds discussing seasoning here:
http://chowhound.chow.com/topics/785489#6614031
Once they're seasoned well and looking good I just rinse them out and give them a quick wipe down with a lightly oiled rag after each use (we keep a paper towel in the lard can for this). Don't get them to hot with the wrong kind of oil in them or you can end up with the gummy mess issue again which can mean stripping and re-seasoning (sometimes can get it off otherwise, but not always).
We also have a couple of enameled Le Creuset pans. We DO NOT use the plain cast iron for much that is real acidic as that eats off the coating and removes the polymer nonstick (quick dishes are ok, but baking anything acidic like a tomato dish for several hours is sad pan making). The enamel coated cast is however great for that sort of thing.
The two we have are:
http://cookware.lecreuset.com/cookware/product_3-3/4-qt.-2-in-1-Pan_10151_-1_20002_41069_10015 (ours is a lot older but the same design, reportedly the frying pan is now nicer actually)
This is absolutely a great piece of cookware. We use it for soups, stews, curries, etc.. all the time. You can saute veggies, etc.. in the frying pan and dump them into the pot. Cuts down on dishes as well that way
http://cookware.lecreuset.com/cookw...-Round-French-Oven_10151_-1_20002_10140_21056 (again a much older version, but same rough size/design)
This is our go-to pot for oven based stews and soups and bigger batches of similar on the stovetop. This works especially well for drier slow cooked stews.
Before you freak out on the Le Creuset prices, you can often find them at 50% or so off if you shop around and wait for sales or even less at yard sales, etc. (the list prices are a little eye watering). Some of the cheaper enameled cast has a bad habit of flaking off or chipping in use which sort of ruins the whole point (not all do, lodge is supposedly okish unless you get a lemon, and there are a lot of euro brands I don't know well that end up being sold under various names that are supposed to be ok). Either Le Crueset or Staub are definitely good if you just want something that works, Staub seems to be slightly prouder of their stuff for no apparent value add I can see... If you're going off brand things I'd look for are smooth enamel, even looking coating, check a bunch of pans for any chips (especially around the top/lid where they'll show up first) and if you see anything that looks bad move on to another brand.
edit: my old dutch oven was made by Findlay from Canada.