Creating a Gravity Bong

So, I've smoked out of all sorts of things, but not a gravity bong yet. I want to get the setup down for 4/20, so I want to make and use one this Friday.

Now, I know I need the following:

2-liter bottle (with lid to affix the bowl to)
Some sort of socket thing for the bowl (I already own one of these)
Something to connect the socket to the cap (I used a pen cap last time, see below)
Bucket to submerge the bottle in

Here's the deal: This past summer, I made a waterfall bong. I used a socket, which works well, and I will use for this gravity bong. However, when I used the waterfall bong, the smoke was EXTREMELY harsh, it was impossible to take more than 1 hit, as the first hit made you feel like you were gonna die.

I have a feeling the pen cap I used as the connector piece, and the piece to stop any bud from falling through, was burning, hence the extremely harsh smoke. So what I'm wondering here is, have any of you encountered this? What else can be used instead of a pen cap? Thanks in advance for any help you can give me.

Or, if you can get a rounded bowl peice for like a slider bong, you don't need to use a socket or a cap, and it works much easier.
The rounded bowl uses suction to sit on top of the bottle without leaking, and when you've pulled the bottle as far as it can go, no messy unscrewing, just simply pluck it off. And no nasty metal.

i use mostly metal for my homemade smoking items....especially for the stem and bowl area.........so that way theres nothing that can melt

u were prolly smokin weed with a hint of plastic....lol that cant be good

try using all metal/glass for the stem and bowl area if possible

Ya metal and glass is the only way to go but just as darkness said about the tube running into the water good idea i do that to every gravity i make it makes for a much smoother rip!!!!!

I use a trumpet mouth piece as the bowl to my gravity, that or the bowl from my bong

yeah, I put a downtube in mine as well. Mine has like 7 small holes in the bottom, so it diffuses it really well. I like that smooth gb...

Thanks for the responses everyone. I think I'm going to go to the headshop in my area this Saturday, and find a bowlpiece that suits what I need it for... thanks for the input.