Introduction: OR Alpine Bivy Sack: Mod to Keep the Lid Open
The Outdoor Research Alpine Bivy Sack is an excellent option for camping, I LOVE mine, but the weatherproof lid/opening wasn't designed to stay open very well on its own. It can be done, sort of, if you work to tuck it over the support rod, but this is a bit of a hassle and not very reliable. To keep the lid open, I modified mine slightly using rare-earth magnets:
- It's effortless to keep open or pull closed in an instant
- There's practically no weight added to the sack
- No cutting of the tent material
Note - this is not a project for the OR Advanced bivy. The Advanced has a redesigned opening allowing you to set its open position.
For this mod I used:
- The fabric repair kit that came with the bivy sack (glue + 2 swatches)
- 3 magnets: [1/2 x 1/4 x 1/8 Inch Strong Neodymium Rare Earth Ring Magnets N48]
- A little Tenacious Tape (clear)
- ~6" of reflective guy-line cord (the generic cord you tie off your tent or tarp with)
What's the "N48" part of the magnet description?
- That's a product reference to how strong the magnets are. I didn't want something so seriously strong it would be tough to pull apart. N48 is a great balance between stay-openness and release-ness for this application.
Step 1: Attach Magnet(s) to the Top Outside Loop
Using the guy-line, I tied 2 magnets to the outside top loop (this loop is likely to be used if you were to camp without the support pole, shaving grams/ounces, and instead "hang" the top from a tree branch using some cord).
- I used the guy-line cord because it's weatherproof and will last a long time. Use whatever you prefer.
Why 2 magnets?
- These rare-earth magnets are very strong, but also very brittle. Having 2 together helps protect them from inevitable impacts.
- If I find some heat-shrink tubing big enough, I'll shrink that around the magnets too. Better protection from damage and weather.
Step 2: Prep the Lid Magnet Components
I wrapped and glued a single magnet into a small, secure "pill" using a little of the black swatch included with the repair kit. Just folded it tight a few rotations, glued the edges, let it dry, and trimmed the excess. This again protects the brittle magnet a bit, protects the bivy fabric with a minimal buffer, and gives a perfect means to secure the magnet to the lid itself (using some repair kit glue).
Next, I cut a circle of the Tenacious Tape (the size of a large shot glass). This stuff is great/convenient for repairing fabrics like... tent fabric. The shot glass was a good size to contain the "magnet pill" with ample adhesion to the lid.
Lastly, to give a little protection to the fabric on the outside of the lid, I cut a shot glass-sized patch of the same repair kit swatch.
Cut circles: you don't want corners that will peel up/off.
Step 3: Determine the Best Position for the Lid Magnet
Assuming you have the Alpine bivy set up, open the lid (unzip the mesh so it's out of the way). You need to mark where to put your lid magnet, on the inside of the lid. Find the best place where it will obviously & conveniently contact the outside loop magnets. Mark the spot with a pencil.
Do this a few times, to ensure you have optimal placement. Why? Imagine you're in there with the lid closed and you hear something sniffing your pack just outside. You want to be able to flip the lid open and stay put without having to search (blindly and panicked) for the right connecting spot.
Step 4: Attach the Lid Magnet Assembly
Using a dab of repair kit glue, I glued the wrapped magnet to the spot I marked inside the lid. Let it dry a bit.
Then being careful to ensure alignment and no kinks, I covered the magnet with the Tenacious Tape. Just press securely all the way around.
Flip the bivy over and glue the other swatch over the magnet, on the outside. Spread a thin layer of glue on 100% of the underside of the patch, you want full adhesion right up to the edges. It's tough to make repair kit glue look nice, ask anyone. Let it dry.
Step 5: Success!
That's it! The weatherproof lid will stay open long as you want it to. Just flip it open, the magnets will attract as soon as they get vaguely close to each other (no detailed alignment necessary). Takes only a small tug to release.
Works great - I've spent several nights with the lid open and it hasn't released once. Even with tossing & turning... as much as that's possible in a bivy sack.
Should anything eventually go wrong, this set up is easy to maintain: either re-tie new outside magnets or cut a slit in the Tenacious Tape to remove/replace the lid magnet. Recover with a new patch of the Tape (you wouldn't have to remove the original piece).
You could, too, install an internal magnet at the top like you did with the lid, instead of tying any to the outside loop.
Hope this works for you! Good luck and enjoy your nights.