Muzzmod v1
To start you need a crafty or mighty cooling unit and a 18mm to 14mm reducer.
Unfortunately often times when you buy glass from eBay it has some sharp edges. This needs to be remedied.
So out comes the torch.
Ah, much better.
Take your cooling unit apart and save the extra bits to use for whatever.
Cut it in half with a hack saw making sure you don't cut into the bottom portion that your after.
Your left with a pretty rough looking piece.
Get out some medium grit sandpaper and place on a flat surface. Rub your piece back and forth to remove any high spots.
It will look like this when you have it just right.
Now use a clamp to hold your newly made piece to the reducer.
Make sure you get it good and centered.
Now mix your JB Kwik and very carefully using a bamboo skewer apply a thin layer around the edge where the two pieces meet. Try and be as neat as possible. No need to use to much.
And you are finished. Let it cure overnight then wash it really well. Insert a screen and enjoy.