I haven't found the time yet but I still want to play with this. I have some 600 fill weight down in comforters that are still in good shape but not being used.
A few members here mentioned filling the baffles inside a tent because down will be flying everywhere, and that does sound like really good advice.
I watched some videos on YouTube that show how those comforters are filled with down and I honestly think that one might use a small shop vac to do the same thing at home. Here's how I envision it might work:
Put the down in in a baggie and weigh enough for one baffle.
Vacuum the down from the baggie into the Shop Vac.
Set the Shop Vac up as a blower.
Insert the vac hose into the baffle in the bag. Use your hand to close and seal the material around the hose. Turn on the vac for a few seconds to blow the down into the baffle and shut it off.
Seal the baffle, repeat, then sew it all up.
I have an old synthetic bag I want to try it out on. I froze my butt off in it a lot of nights so it will be easy to improve it or toss it. It doesn't have any real baffles, with sides, just tubes, so there will be cold spots but it could be an interesting experiment.
If I envision it all wrong and blow feathers all over the place at least they'll be inside my big car camping tent and I'll just vacuum them up as best I can.