2 Liter Bottle Funnel Insert

Two liter soft drink bottles found in the US can make for some very useful funnels after consuming the contents. However, when cutting the bottom off it leaves very flimsy sides.

I designed a round insert for the cut-open end to stiffen the sides/opening. It's a friction fit and you may have to ever so slightly scale due to potential differences in each bottle. I original designed the ring based on the specs for this 2 liter bottle which stated the outside diameter as 110 mm. That was way too large.

The final dimension which allowed the ring to snugly fit inside the cut-off end was 107.25 mm. You might have to scale up/down by .5 to 1% if the model doesn't fit for you.

There's a 1 mm chamfer around the part of the ring that inserts into the bottle to help slide it on easily.