zipper question

[Brian James]

Can a second "pull" be added to an existing (pre-sewn) zipper?

I have a pyramid tarp with a single-pull zippered door. I'd love to be able to zip it up completely to the ground, and then pull a top zipper down 12-18" in order to make a high vent.

I'm not about to cut the zipper out and sew in a new one. But it occurred to me that there might be a tool that can take apart and then reassemble the teeth on the zipper so that I can add a second pull.

Does that make sense? Can it be done?

[Vick Hines]

What you can do is remove the existing zipper pull and install a double-sided pull of the same size. Outdoor Wilderness Fabrics (owfinc.com)has a good selection of pulls. If you are not sure about the size, just order one of each. They are cheap. This is not as practical if it is a separating zipper, but it can be done. Lightweight tents and tarps usually use #3 (smallest) or #5 (medium).

If it is a non-separting zipper, remove the stop at one end of the zipper (I prefer to work at whichever end results in the zipper being closed), pull the existing pull off, get the teeth clear so you can access them and line them up (sometimes tapes are folded over and get in the way, if so, unstitch the folded part), sear the edges of the tape so it does not fray, then work the new pull onto the teeth. Make a new stop by stitching over and around the teeth with button thread.

For a separating zipper, you may have to buy a matching separating zipper of the same gauge but with a double pull. Sometimes you can buy them separately, but not usually. On the new zipper, remove the stop at the top of the tape that the pull stays on, and remove the pull. On the currently installed zipper, cut the stop from the top of the tape that holds the pull, put the new pull on and make a new stop with several stitches of button thread.

[Brian James]

Wow; thanks for the great info.

It occurred to me last night that maybe David Olsen of Oware intentionally left out the double-pull zipper for strength reasons. It's a pretty meaty zipper, but then again it's holding together a lot of square feet of fabric. Maybe a double zipper would create a failure point?

I got this idea from looking at construction at the top of the zipper as i tried to take it apart: very heavily built there. Now I'm gun-shy on modifying the design.

Anyone else tried it?

[Steve O]

Brian, the MH Kiva Lite has a double pull zipper. That being said, I'd guess that strength isn't an issue, since the Kiva is a pretty beefy shelter.

I too would like a 2x zip on my Shangri-La. Venting options would be a bonus, but my main motivation is for ease of opening. If I pitch the shelter to the ground, I have to stretch deep down to grab the zipper, possibly getting condensation on my head and arm.

[Ron Bell / MLD]

The double zip is an interesting idea. I could see some venting options like you mentioned if a really large sprung vent covered the top of the zip. You would need a long zip to the top of the mid and also a really bomber zipper, at least a #10 coil. The vent spring material would also need to be tougher/heavier to spring a wider vent flap.

A #10 would weight about 4oz more than a #5 in Mid.

Also a note on all mids (SuperFly shelter and other mid types too) and zips:
ALWAYS make sure tthe bottom zip buckle is fastened every time you pitch the mid or zip up or down to keep pressure off the zip teeth and avoid blowing out the zipper.

Mid door panels can generate a lot of force than can get focused onto only a few teeth of a partially zipped door with the buckle unfastened.

[Vick Hines]

Adding another pull will not weaken the zipper.

[Scott Christy]

Agreed Vick.

I suppose one unusual benefit of putting another pull on your zipper for long term expeditioning is that the top (less used) pull could be cut out and switched directions to act as the primary pull if the primary pull fails. And in the meantime you'd gain the slight added venting utility. I could see it especially being useful on the Hut 1 or Shangri-La 1.

[Brian James]

I had my 'mid out in about 20* temps for testing (read:playing) on the weekend. I pitched it tight to the snow, and with one person the humidity was pretty gnarly in there. I could feel it in my mouth, and every exhale looked like I was smoking a cigar. (Granted I live in a coastal area that's really humid, and it wasn't cold, etc.

Solution: open the door. I was just wishing for a way to make a "high" vent to pair with the "low" vent that I dug under the opposite side.

I also found that leaving the zipper unzipped but doing up the ample velcro on the flaps made a sort of highly-porous closure to help it breathe. But in the end, I think it's going to be "door wide open" when cooking and socializing and hopefully "top unzipped 18 inches" when sleeping. Thanks again for the zipper advice all.

Ron: after reading the warning on your site about always buckling the door before zipping it, I decided to pitch the 'mid with less tension on the "door" side. I changed the angle on the door-side stakes so that the door side hung slightly loose. Not that this would be practical in a storm, but for a quick pitch to dodge weather this takes the load off the zipper.

[John G]

I'd imagine that adding another "zipper buckle strap" (like the one at the bottom of the door) about 18" from the top of the zipper would take the stress off the zipper if a door with a double zipper was open at the top. I imagine this would only weigh 1/4 to 1/2 oz – way lighter that the 4oz switching to a #10 zipper to get the beefier teeth would add.

I also think adding a vent cover with a double layer of weed eater cord in the edge to hold it out like an awning(like Roger Caffin's tents) would work well in this application.

[Brian James]

Now you're describing my dream pyramid. Could you add flaps around the edges to pile snow on and reef points so it can be pitched shorter in a gale?

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