I just finished converting a Vango Venom 150 this morning, and I'm really pleased with the results.
I wouldn't touch this sleeping bag with a barge pole normally. As you can see from the photo, it's ridiculously overbuilt. However, I found it in TK MAXX (a discount store chain in the UK) a few years ago. Someone had taken it out of it's stuff sac in order to look at it, and then just left it on the shelf. Not knowing where the stuff sac had got to, the staff marked it down to £10.00 (from about £50.00). I found the stuff sac on the shelf nearby (but forgot to show it to the shop assistants, oops). Anyway, at £10.00 who cares. I thought it would make a good overbag for my Skywalker 2. Then last year I found this article and began to think. Because of the construction (as can be seen), the bag could not just be turned round so the zip area is beneath the sleeper. It had to be removed, and completely re-sewn. I removed the hood first (very straight forward) and hemmed it up. Then cut down the back panel by the zip, and sucked out the down using a vacuum and some organza netting. I cut out the v section and hemmed it up. It needed binding at the bottom where it is impossible to hem, this adds some strength aswell. Then I put the down from the hood and back panel into the top sections as I cut down by the zip (again, a cardboard tube and organza helps suck up the down, then you just blow it back into the bag). Then I just sewed the two panels back together. It went much better than expected, I'm really starting to get the stitch balanced now. Here's a picture of the back:
Manufacturer's claimed weight, 580g
Min Temp +7 c
Cost new, over £50.00
Weight after modification, 390g
Min Temp, about 5 c
Thanks for a great article Jay!