Hi Simon,
We have been filling our Composite 5KG cylinders for many years. Either with Propane when available or Butane. I am not a techno person as you know, but the decanting works well. We carry a selection of fitting for different countries, and if your composite bottles are of the type where you can see the level of liquid gas in them, there is no necessity to even weigh them. Please note you must empty the bottle completely of propane if you wish (or can only obtain ) butane or visa versa.
The other advantage is that those on Camping Gaz bottles pay through the nose for an exchange cylinder in Europe We just buy a local exchangable bottle and fill our own tanks at a quarter of the cost. I can explain more when we meet.
Cheers Brian s/v Darramy

Hi Simon,
Although I have never done so, I have friends who decanted propane in Europe for years in order to keep using their American bottles. The bigger trick is to find to find the proper proprietorial fittings and attach them to the decanting hose. Here is a URL for a youtube tutorial (which I did not watch, but suspect is good, https://www.youtube.com/watch?v=dATQPGm8_jw).
I believe that a bottle is just a bottle and can be filled through decanting, composite or otherwise.
I hesitate, without permission, to put someone’s name on a public site without permission, but anyone can write me off line and I can set up contact with American boats who have decanted and are willing to talk about the ins and outs of doing so.
I took our Icelandic bottle through Greenland and on to Newfoundland where it hopefully will find a home on another boat going east.
My best, Dick Stevenson, s/v Alchemy

I would like to seek advice. We have 2x 10kg composite propane bottles we acquired in Iceland. We cannot get these commercially refilled in Greenland and we don’t really want to replace them with the indigenous steel ones. I understand if I connect the regulator on our empty composite via a hose to a regulator on a Greenlandic steel cylinder and the hold the latter upside down and above the composite then the liquid will flow into our composite.

Before I do this can someone please confirm I’m not going to blow up the harbour. I am a little nervous so advice please.
Simon