question about keggles

So, I have a keggle with the top cut an 2 welded fittings on it. Obviously, the bottom fitting is for a ball valve, but what is the upper fitting for?

If I'm going to use this as a boil kettle can I just seal the upper fitting with a stainless steel plug?

Also, I am worried about the pipe thread tape on the ball valve and plug at high heat. Is there a special kind of thread tape that I need?

Thanks in advance for any help.

Normal thread tape is fine
How high is the second fitting?
Could be for a thermometer but if it's real high it's a recirculation port for a more involved type system. Got pics?

yeah, here's a pic...

Yeah, that's for the thermometer. That's about where mine is.

So, for the bottom port, can I just attach a nipple and ball valve to the bottom, or does something need to go on the inside part of the keggle

you'll need to get some sort of dip tube on the inside part. a compression fitting with some soft copper tubing works well, there are a ton of dip tube options though. if you don't use one, you'll be hard pressed to get all the liquid out.

Don't you want to leave the hop and break material behind though?

When I rack from my current kettle, I usually leave about a half gallon or so behind. Seems like a dip tube would pick up all of that stuff.

you'll hear conflicting opinions on that. you can use a stainless steel scrubby or something on the end of the dip tube to filter, or run the dip tube to it still leaves .5-1 gallon behind. if you use no dip tube, you'll be surprised how much it leaves behind, probably 2.5 gallons or so. personally, i try to get as much out of the keggle as possible and let it settle during fermentation. no off target effects yet.

You'll want a siphon tube that at least turns down near the side wall and hits the bottom off center. It doesn't have to reach all the way down into the center depression. As mentioned, there's about 2.5 gallons of space to the coupling.

You will want something like this for the inside of the bottom hole with a butterfly valve on the outside.

http://www.brew-magic.com/ketl_acc_siphon_kit.html

The middle fitting will be a little high for 5 gallon batches but right on for 10 gallon if mashing with it. If boiling with it just plug it off. A bazooka screen works great inside of the ball valve for screening.
Cheers

The standard fittings look like this (this is a 7.5 gallon keggle, but you can get an idea:

I have my tube turned toward the bottom side. Still need to use the SS scrubie.