Sleeping bag project

Mid 2012 I bought a Rab Neutrino SL 200 sleeping bag. To recap, this is a top bag with virtually all of the insulation on the top of the bag. The underside has some insulation underneath your legs, Primaloft 100, but none under your torso. The idea is that any down underneath your body provides next to no insulation and therefore is superfluous.

P1030645Unfortunately, I’ve never quite got on with this sleeping bag. Even with a good sleeping mat, I found it a bit cold on the underside. I was thinking of selling it. However, I had a brainwave. Why not add a slab of synthetic insulation in the sleeve where there’s no insulation?

P1030646Initially, I thought of a DIY solution of adding some fleece. Then I thought of adding something like Primaloft. As this would be beyond my abilities, I contacted Marco at As Tucas. He uses Climashield APEX insulation for his quilt, which is similar to Primaloft. After an exchange of emails, I’m getting him to use APEX 167 which is heavier grade than the Primaloft 100.

Synthetic insulation should be a bit warmer than down when compressed and turn the bag into a decent 3 season sleeping bag. Marco reckons it will add less than 100g to the weight (80-90g?), which would take the total weight to less than 673g. For comparison, my Pipedream 400 is 740g.

It’s possible that the Neutrino might be even warmer than the Pipedream as the down quality is higher and it has as much down on the top side of the bag. Hopefully the synthetic insulation will be warmer below my body and I will be able to dispense with a sleeping mat cover. If so, the total weight saving could be around 200g. How much will it cost? £33 plus postage costs.

I think it’s worth a punt, so I’ve posted my bag to Marco today. It will be an interesting experiment. I’m surprised that there aren’t hybrid sleeping bags with synthetic insulation on the underside, or at least, I’ve not seen any.


12 thoughts on “Sleeping bag project”

  1. The bag its self is top kit. Used one the TGOC 2013, and only got cold when turned on my side asleep, or failed to get some heat into the bag before falling asleep. Overall good kit. So if your idea works you could have a good bit of kit. I would also have a collar added as its going to make it really efficient.

    1. I thought about adding a collar but it’s not straight forward to retro fit. I also found the baffle around the hood is quite thick and seals in the warmth quite well, so I decided not to go for a retro fit collar. I do agree that a collar or neck baffle is very efficient at sealing in the heat. The one on the Pipedream is particularly good.

      Addendum: I think I’ll ask Marco to see what he thinks.

  2. An interesting idea which makes perfect sense. Good to know AS Tucas can carry out custom fits as well. I look forward to seeing the end result.

    Similarly I was think about replacing an old RAB Quantum bag but had it cleaned and customised by Mountainering Designs in Cumbria. They overstuffed the baffles around the chest with a higher quality down and it noticeably improved the bag with little weight gain.

  3. It will be interesting to see how the modification goes. I tend to spend most of my time asleep on my side, so this bag wouldn’t be too useful. That said all 3 of my bags are from the Rab neutrino endurance series and each has been very good, especially with regard to warmth and upper torso space.

    1. I’m a side sleeper as well and I don’t think top bags work well for side sleepers. Nor do quilts unless they are large.

  4. I’ve an ME summit 300 that’s got very little insulation in the back also, I’m a side-sleeper & it doesn’t work for me. I’m selling it & replacing it with a quilt !

  5. It will be interesting to see when this comes back. I’ve considered using a seam ripper to open up a cheap sleeping bag and fill it with purchased down…but never had the guts to. Found a cheap warm small sleeping bag, but definitely not as light as the pack you’ve got!

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