The history: I came up with this idea after a little experience I had a few weeks ago. A group of us decided to tube down part of the Rainbow River. I brought a waterproof box to put keys, cash, credit cards, all the stuff I find amazing that people want to bring out on the water, but don't take carrying them into account. One of the two smokers in the group asked if I would put his cigarettes in the box. When we got in the river I found that the box had slipped off my lap into the water. I had it clipped to the tube handle, but when I pulled it up I discovered that the seal had failed and water was inside. The keys, cards, even cash was fine, the cigarettes suffered. I really felt bad, the guy was good natured about it, but not having a cigarette for a couple of hours was rough on him. So I got to thinking about a personal container that cigarettes would fit into, but would be inexpencive incase of loss.
I was thinking on this while making a PB&J and got to the bottom of to the peanut butter. I put the lid on the empty jar and put in aside on the counter but it tipped off into the sink and landed in a pan of water. It floated, of course, but because of where my mind was I saw a waterproof container, not just an empty jar. And yes a soft pack of cigarettes fit, I borrowed my son's cigarettes to check, with plenty of room for keys, cards cash - and a lighter.

Step 1: Getting Ready

Material:
*An empty peanut butter jar
*An old bike inner tube
*An old key ring

Tools:
" Scissors
" Epoxy
" Pen
" Rough sand paper, 100 grit or so
" Mixing pad
" Mixing stick

Actually any jar will do for this project - just make sure it is plastic with a screw on lid. I used an 18oz jar.

Wash out the jar and take off the label. A little Goof Off, or some such product, will take off the old glue that held the label. Make sure to wash the underside of the lid.

Epoxy can be messy; I protect my work surface no matter if it is - kitchen table or work bench.

Have something disposable to mix the epoxy on, and something disposable to mix the epoxy.

Step 2: Inner Tube Gasket

1.Cut the bike inner tube crosswise.

2.Place the cut end on one side of the jar lid; it should over hang a 1/4".

3.Pintch the tube where it over hangs the other side of the lid, back off from the lid a 1/4" and cut the inner tube crosswise where you are pinching, eye balling it is just fine.

4.You should have an approximate 3 inches

5.Cut up the side of the tube and flatten out.

Step 3: Cutting the Gasket

1.Place the lid on the flattened section of inner tube. There should be plenty of tube around the outside of the lid.

2.Hold it in place and draw a circle around the lid.

3.Cut the circle out, but cut on the inside of the line.

4.Put the circle of inner tube inside the lid to see how it fits.

5.You will most likely have to trim a bit more, but keep it as tight to the edge as possible

Step 4: Prepare the Gasket

Rough up the circle of tube with the sand paper. This gives the epoxy something to grab on to.

Rough up the underside of the lid with the sand paper.

Rough up the top of the lid, too. This will be needed latter, but might as well do it now.

Step 5: Attach the Gasket

Follow the directions on the epoxy package. This is a very strong glue, be careful while using it.

1. Place equal amounts of the two parts on the disposable mixing pad. As you can see I used an old envelope.

2. Mix the two parts together well with the disposable mixing stick, in my case an emery board from a local realtor.

3. Spread the mixture all around the edge of the inner tube circle.

4. Carefully, insert into the underside of the lid.

I screwed the jar on to the lid just enough to keep the circle in place while it dries. Do not tighten down hard, this will squeeze the epoxy mixture thin and it may not get a good bond along the edge.

Step 6: Attach the Ring

I happen to have a key ring that has a short piece of web strap on it. This made for a good way to epoxy the ring to the top of the lid.

1. Mix a small amount of epoxy.
2. Apply to the ring.
3. Hold in place until dry.

Really anything to which a length of rope can be attached will work.
You just need to be able to tie the jar to your river tube, kayak, or whatever so when it falls off it doesn't float away.
In the first waterproof jar I made I cut a half inch section off a cheap ball point pen tube and epoxied that to the top of the lid and attached a short lanyard.

Step 7: It Worked - Really Well

We went back to the river a few weeks latter. The peanut butter jar was a hit. Everything that went into the jar was kept dry; and they cramed a lot of stuff in there.

One of the unforeseen benefits of the height and shape of the 8 oz jar is the cigarette pack fits in in such a way that other things can be put around the pack the cigs can be got to without unloading.
I am not advocating smoking, but fascinated by the mechanics of this unexpected benefit.