Pot size question

Im doing my first partial mash beer recipe and I have 4 pounds of grain. I have a 4 gallon pot and im wondering if that is big enough to hold all my grain with sufficient water? Other then this pot, my outdoor pot is something huge like 20 gallons which im guessing is too big?

Basically I have these two pots at my disposal and need some advice. Also what can I use to hold the grains, my nylon sack i currently have is to small. Can i go to the hardware store and get paint strainer bags? Or is there a common hosehold item i can use.?

Thanks

http://www.rackers.org/calcs.shtml

Use the "Can I mash it" Calculator. Looks like you'll only need about 2 gallons of space or less depending on your thickness.
Paint strainer bag will be fine as long as you find one big enough.

4 gallons will be plenty for 4lbs of grain.

how much water should I have in the pot?

Depends on how thick you want to mash. Most people mash at about 1.25 qt per pound of grain but you can go thinner than that with that amount of space. Use the calculator linked above.

You need just enough water to keep the grain suspended. I believe it helps remove some chance of scorching while heating. Also it keeps the enzymes from being too thinly dispersed, so you get better conversion.

Oh, this thread is referring to cooking ware... I was way off.

Seriously though, the amount of water you need for striking depends on if your going to do a mash out, double batch sparge, single, etc.