I've made a fewwww homemade bongs before and the only one I still really use went a little something like this
I took a 3/14 socket and drilled a hole in the top of a small sprite bottle and fit the socket airtight, then I took the tube of a pen and fit it to the hole on the bottomside of the top and packed around it with clay to be airtight, then filled the smaller bottle about 3/4 full and fit the bowl around the top of the sprite bottle until it was airtight. then I drilled a hole in the top part of the bottle and used some tubes from a nebulizer in it and clayed it airtight, that tube ran from there into a 2l bottle about 1/4 full of water into the bottom. Then I drilled a hole in the top of the 2l and used a hooka tube with mouthpiece and sealed with clay...
Perfect for inside smoking because no smoke escapes because its trapped in the 2l bottle.
Then to take the hit you can either use hooka mouthpiece or screw of the lid of the 2l bottle, cover the socket with thumb, and hooka mouthpiece will act as a carb.
Long I know, sorry, I ramble.
