Hi-Viz Key Float - Recycled Champagne Cork

Insert a cork mid print. Pause or set a colour change just before the internal fillet (around layer 253 at 0.2 mm layer height). 

The internal void will accommodate a cork of up to 34 mm diameter x 47.5 mm height - that is larger than the several champagne corks I had at my disposal to measure (hic). The air space around the cork will increase buoyancy, and if that leaks and fills you still have the cork to keep your key afloat. 

It takes about an hour and twenty minutes to print and gives you a great excuse to celebrate with a bottle of fizz!

If you wanted to print this without the cork it would float but I worry that printing imperfections would cause the print to be slightly porous and over time it would fill with water and sink - my printer is not always so good! I expect it would float very well for long enough to fish the key back out though and would probably save you from a lost key. There may be ways to help 'seal' the print too, but I have not investigated that.