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 # EU-Propane-Tank-Adapter
 
-This is an adapter for North European propane/butane/lpg tanks, to connect a 9mm hose directly to the tank.
\ No newline at end of file
+This is an adapter for North European propane/butane/lpg tanks, to connect a 9mm hose directly to the tank.
+
+The official name of this thread is "POL / W21.8mm x 1/14 inch LeftHand thread".
+
+Required additions:
+- A 11.8mm-2.4mm O-ring to make a sealed connection.
+- A M10-0.75 hose barb.
+- An optional extra O-ring 5.8mm-1.9mm behind the hose barb.
+
+These O-rings are fairly common.
+
+I printed this with PETG. 40% cubic infill, 3 walls, 5 layers on the bottom. The smaller diameter hole should be on the build plate.
+
+***This adapter should not be used to connect appliances directly to the tank, as it has no regulator!***
+
+*Do not tighten this plastic adapter as you would to with a metal one! The rubber O-ring(s) make the seal, once they make contact with the tank give it a 1/4 turn more.
+If you overtighten the adapter you risk layer separation!*
+
+The purpose of this adapter is to provide a direct unregulated connection to the tank.
+This can be useful when filling one tank from another.
+
+I use this to fill the EU tanks on my boat, using foreign countries local propane tanks as a donor.
+My tanks are made from fiberglass and I don't want to exchange them for steel tanks which rust terribly on a sea going vessel.
+
+## The gravity fill procedure
+
+1. Connect both tanks together with a direct, unregulated, connection.
+
+2. Hang the donor tank upside down above the receiving tank. It helps if you cool down the receiving tank while the donor tank is in the sun.
+
+3. This procedure can take some hours, depending on the hose diameter, temperature difference of the tanks, etc.
+Keep an eye on the tanks during the entire procedure.
+The 3D printed tank adapter should be strong enough, but printing or material defects can result in a too weak adapter, which might burst at some unsuspecting moment!
+
+4. Check the weight of the tanks to monitor the progress.
+
+
+