This instructable walks through the process of making a mouth-friendly edge on an aluminum bottle turning it into a Cool Reusable Metal Tumbler Cup.
The steps outlined here are, stand-alone, instructions to make a complete Metal Tumber from an aluminum bottle; suitable to use as a lightweight tankard for all your favorite beverages.
(I recommend the chilled kind. Remember science?...aluminum is an excellent heat conductor; you don't want hot cocoa burns on your fingertips as well as the tip of your tongue!)
However... those of you familiar with the Aluminum Bottle Backpacking Stove,
( https://www.instructables.com/id/Aluminum-Bottle-Alcohol-Stove/ ) will also recognize the technique demonstrated here, as a means for creating light weight cooking tools to accompany an alcohol stove.
The video below shows these Aluminum Bottles & Tumblers in use as a lightweight backpacking cook / storage system.
The bottles are obviously used for beer (and I know at least one soft drink) however, availability of either (or any for that matter) varies by region.
As an added note: I had reservation about posting an instructable that featured an alcohol container as it is not appropriate for all. I would have perfered to use a soft drink bottle however due to availability in my area, I only have found the beer bottle variety.
But ultimately, its the aluminum bottle that we're interested in, not necessarly the beverage. Dispose of the contents as you deem appropriate, or seek out empties through another source.
(Along the same lines: I am pretty sure not everyone who has built a bar-b-que from a steel barrel personally bought, and consumed the 50 gallons of Crude Oil inside to get to an empty drum.)
Step 2: Cut the Neck Off
Aluminum bottles are a thicker gauge than aluminum cans so utility knives won't work.
I use a hack saw to cut the bottle. Cut around the diameter rather than trying to cut straight through. The saw teeth will catch on the edge of the bottle and leave ragged edges.
Step 3: Start the Flare
Start to flare the edge of the bottle. A 1" diameter wooden dowel works well.
Start by placing the dowel in the bottle so it is resting on the bottom. Rotate the dowel around the edge of the bottle.
Use a "stirring" motion as you press the dowel outward against the bottle's edge.
Gradually pull the dowel up off the bottom of the bottle while stirring to increase the angle of the bend.
Step 4: Rolling the Edge
At this point, place the bottle on a flat surface. A soft wood surface works well. The bottle will slightly press into the soft wood giving it some grip. This helps keep the bottle from slipping while rolling.
Tilt the bottle it so that only a portion of the edge is in contact with the wood. Press down on the bottle and rock it in a circular motion; keeping only a small portion of the edge in contact with the wood at any given time.
The second photo shows the rolling in a sequence of pictures
Do not try to do all the bending in one rotation.
Gradually increase the downward pressure on the bottle as you roll it around several times. You want a nice controlled edge without any kinks or variation in flange length.
The third photo shows the flange after rolling
Step 5: Increase the Roll Angle
Eventually you will be rolling the bottle almost on its side to get the cut edge of the flange as close to the bottle's side wall as possible.
Step 6: Closing the Edge
The edge needs to be "tucked in" for the start of the next roll. The goal is to not collapse the cross section of the rim with a hard crease. The edge wants to curl inward.
Step 7: Second Roll
Use the dowel to flare the rim just like for the first roll. Then rock the cup on a flat surface just like before.
Be careful that the first fold does not coming unrolled as you start the second flare and roll. The cut edge needs to be tucked into the second roll.
Reference the second picture.
Step 8: Finish
Adding just the start of a third flare, will help to close the gap between the sidewall and the second roll.
Stretch the rim by placing the dowel in the bottle and repeat the stirring motion. This will bring the rim back from any "out of round" bending that might have occurred.
The stretching also increases the "hoop tension" on the rolled rim to finish pulling it tight against the side wall.
The photos show the finished product with a tight fitting rim.
Step 9: Ready to Use
The finished Tumbler won't crush or have that "oil can" flex like aluminum cans. They feel, and look like any other tumblers you could use and store in your cupboard.
Go ahead, make a whole dinner service worth of them!
Step 10: Additional Camp Use.
The video in step 1 shows both of these in action.
There are designs for aluminum can cook pots however they don't compare to the strength and durability of an aluminum bottle.
The Stove Instructable found at this link.
Note: Because the cooking pot also stores the stove, the bottle was stretched to fit over the stove before the edge was rolled.