Zipperless net tent door with rare-earth magnet closure

[Lester Moore]

Has anyone used the following design to make a zipperless door for a net tent or tarp? There’s a pocket around the perimeter of the door opening to sandwich the edges of the netting door panel between magnets. The magnets are sewn onto the edges of the door opening, the netting door, and the door pocket (see graphics below).

The plan is to make a half-pyramid net tent similar to the SMD Serenity, but lighter (under 7 ounces) and with partial solid walls as my first MYOG project. Seems like the pocket would create a reasonably good bug barrier to all but the most tenacious bugs (i.e. ants) and hold up to reasonable wind forces? Not looking for a tight seal – just enough to keep out mosquitoes, spiders and common insects and to hold up to moderate winds. Do you think this would work?

These rare earth magnets seem like good compromise between field strength and weight for this application: Magcraft NSN0640 rare-earth disk magnets, 0.5″ diameter, 0.0625″ thick, 0.05 ounces each and 2.7 pound pull force

https://www.magcraft.com/magcraft-nsn0640

 

[David Thomas]

The first tent I camped in, on a Scout trip, was zipperless (insert Erica Jong joke here), WWII-era, canvas pup tents with metal buttons and corresponding button holes.  A few years later, the troop upgraded to Korean-era tents with snaps.

The 2.7 pounds is probably bare-magnet to bare-magnet, not with two layers of fabric between them.  And that rating may be for straight pulling – they might slide apart at an even lower tension.  A simple button / button-hole – even a small one from a shirt – can easily withstand more than 10 pounds of force in any direction.

Magnets would be cool, for sure.  And simplify water-proofing (versus buttons that need an additional flap to be as secure.  Either magnets or buttons would be much more reliable than zippers  Dirt and sand and ice would be far easier to deal with than with a zipper or with Velcro.

[Ben H.]

I think it could work, though I imagine some persistent mosquitoes might be able to get through.  You will need to play around with the number and strength of magnets to get the desired seal/wind resistance and still be able to open it quickly.

My only concern is that I’ve had a problem with rare earth magnets breaking and falling apart.  They are not metal and they are very strong.  Snapping together can often result in fractures that grow with use.  I bought the cheapest ones on Amazon.  Others may work better.

[Franco Darioli]

I put a hint on another thread about possible problems with that idea.

David already has mentioned the two biggest problems

1. they are very brittle. They can crush/damage themselves when they snap together. That would probably easily happen on a tent door
2.  they are hard to pull apart but slide apart with little effort. That would easily happen on a tent door….

If they don’t slide with too much effort , you won’t be able to separate them by pulling the door panels apart.

So the hard part would be to get the balance between too strong and bulky and not strong enough to keep the panels shut.

 

[R]

What are the goals/problems you feel magnets address better than traditional closures?

If you’re interested in the ease of ‘self sealing’ your design has a flaw in that you’ll have to manually open each base-pocket pair to insert the door.

If you can 3D print some plastic bits, you may have a winner. Plastic housing for the magnets will protect them from impact fracture, but more significantly you can create a sort of 2 part latch, where the plastic takes all the tension and the magnets just keep the latches engaged.

I’ve also thought about zipperless doors, for the sake of weight and durability. My approach involves a single latch, maybe Velcro, at the apex of the door, relying on tension to seal the edges. I wouldn’t rely on this for a rain fly in high winds, but it should work for a bug net.

In the diagram on the left, the double layer area is a pair of flaps sewn together where they meet the single layer area, and separate, exposed edges where they face the door opening. The lower corners of the door panel sit between the flaps, and the apex of the door is inserted between the flaps at the top of the door opening to close the door. The single latch is at the top, between the flaps.

With the apex of the door inserted between the flaps, pulling up on the door presses the edges of the door against the seam where the flaps meet the single layer area, forming a seal.

Ideally these are all catenary curves, but it’s not that important. The exposed, open edges of the flaps are corner to provide tension to pull the edge of the single layer area towards the middle of the doorway. This counters the force generated by pulling up on the top of the door.

I haven’t actually built one of these yet and it relies on the tension of your pitch to work. If a stake pops, you may lose the seal around the edge of your door.

 

[Nick Smolinske]

This is my kind of thread! I’ve been prototyping a design very similar to Rene’s in my head for the past couple of weeks. But not quite as refined. As he said, the tension is the issue. I was thinking it might be better to have the tension of the door separate from the structure, with extra tie outs below the edges of the triangular door. Then you could tension those separately.

Or, I could maybe just have a couple adjustable guy lines to pull the corners of the bathtub floor out towards the corners of the tarp. It’s possible that by itself would provide enough tension.

Instead of velcro at the top, I was thinking just a plastic hook and a loop of grosgrain. Seems easier to use.

[R]

Cool. I’ve been hoping to make this operable with a single hand. Maybe more like a clothes line than a loop. In a 2 person shelter it also has to be accessible from either side – e.g. closed from the inside and then opened from the outside. This while maintaining a complete seal to the tip.

[Sam Farrington]

The doors do not need to be insect proof if there are also netting doors further inside, as is common on many designs.  But what is the weight of the magnets.  And if they slide apart, separation by high winds appears likely  The need for tension was also mentioned, and a lot of it is needed to keep gusts from separating the outer doors and violently entering the inner tent.  A velcro reinforcing fastener at the separating end end increases strength and adds very little weight.

Something akin to the slider arrangement on a zip-lock bag, but sturdier, might be a way to reduce weight.  For now, the YKK #3 coils may be the lightest for the inner door(s), weighing 0.1 oz/yd (not including sliders). .  Warmlite uses beefier YKK coils, weighing 0.12 oz/yd which are stronger for outer door(s) at a minimal weight penalty.   Don’t know if they still sell parts.

So focusing on limiting the number and length of zips, and replacing the solid metal pulls with lighter cord loops may be best for now.  There have been reports of problems using cord for pulls, but i’ve never experienced any.  Maybe it is a design, not a materials issue.

[Nick Smolinske]

Ooh! What if we combine both of these ideas? Take a triangular net tent door that fits tightly into overlapping mesh, and then use two rare earth magnets for the latch at the top of the door.

It would have some advantages over my mitten hook concept, namely that the door could be pulled more tightly up against the overlapping mesh. And it would be easier to use than velcro, you could just sew pull tabs beneath it on both sides of the door.

The brittleness issue is easy to solve, because we only need two magnets – so we can make them large enough to work through a protective fabric covering. No worries about added weight because the area will be so small, so you could use whatever fabric you wanted.

The other nice thing about having just two magnets is that you won’t have any magnets stick to each other when the door is open. You still have the issue of sand potentially sticking to them depending on the iron content of the sand, but if you always lay the door inside instead of outside then that wouldn’t be a big deal.

[Lester Moore]

Using some of the above ideas from Rene, Nick and Sam, below are depictions of a magnet-free and zipper-free door. Instead of magnets, simple hooks and D-rings could be used to latch the netting door in place. The top of the door would be sewn to the nettent, but the rest of the door would be free so it could be tucked into the doorway perimeter pocket.

The tension required to form a tight pocket around the doorway perimeter comes from 5 lines attached to the tarp apex (trekking pole supported), the front undersides of the tarp (approx 6″ off the ground) and the tarp’s front corner stakes at ground level.

 

[Ryan W]

Hi all. Did any of you make a net tent door with magnets and/or clips. I’ve been thinking about doing the same thing and would love your feedback on how successful you were. Would love some pics of the project. Thanks.

[Jerry Adams]

I’ve added ties – 4″ long length of flat shoe lace.  Maybe 4 pairs from top of tent to bottom.

That holds better than snaps or magnets

It’s not waterproof, but I never put anything directly under it anyway, because that’s how I get into and out of the tent

[Sam Farrington]

Insects and other critters will find a way to get in and suck your blood if there are any openings.  Simply because that’s what they do to survive.  Granted, there are actually some places these critters do not frequent, and even cowboy style is OK.

[d k]

The shelter I made has no zippers – fly doors clip similar to Duplex, the netting inner door is just one extra wide and long flap that hangs down – to get out, you lift it up.  The shelter has a clip-in bathtub floor, and the net flap tucks into it, held in by clothing, shoes, gear, etc.  The net door is a triangle wider (and longer up-down direction) at the base than the door opening, which gives it enough play to be able to lift up.  The two sides are sewn onto the fly-to-door seams, and the bottom hangs free.

https://backpackinglight.com/forums/topic/104473/

 

[Sam Farrington]

Have a jacket that has similar magnets that close each of the chest pockets – two closures per pocket for eight discs total.  They are very secure, but have not really gotten used to using them, so lean toward using the pockets only for items that will seldom be used, such as a face mask if hikers approach from the other direction. (They don’t know I’ve been vaccinated and boosted twice.)

With respect to weight, two of the discs weigh about .12 oz if I got it right. By comparison, one running foot of the beefed up #3 YKK zips from Warmlite weigh about the same, .12 oz., but 4 times that for a sloping vestibule tent door that runs 4 feet from end to end.  Because this is an outer door, with a cat-cut, more than one pair of magnets would be desirable, and even then doubt the door would be held in a taut cat-cut when the door is closed.

For a vertical inner netting door, lighter #3 zips weigh only .1 oz per foot; but for a netting door that opens on either side, using zips in an inverted T shape, that’s maybe 11 feet of zipper, or 1.1 oz.  So it turns out that the inner netting door that hangs vertically weighs more than the beefier zip on the outer vestibule door that slopes to just above the ground.  But what creates the increased weight is greater zipper length on the netting door if a completer seal of the inner tent is desired.  Someone mentioned ants.  There are probably a number of other crawling pests about also.  Fire ants?  And I had a pup who would let herself out by using her nose to undo the zipper.  I’ve also seen Daddy Long Legs somehow penetrate very small openings, and that was a whole family of them.  Harmless, but annoying. (Note:  Do not use Tulle or the like because want netting doors to last.)

So have wrestled with these dilemmas for ages, and for a solo tent, finally decided to leave the vestibule and netting on the rear of the tent zipperless, and extend the floor into what would otherwise be a vestibule.  This adds quite a few more square feet of floor space, and reduces the zipper weight by about half.  (But probably would not work on a duo tent.)

Granted, there are issues with zippers failing.  However, with good campsite selection, I’ve not had them, even without cleaning zips before trips (although probably should.)  For areas where zippers tend to fail, would seriously consider the magnets or other device to secure doors.

[Roger Caffin]

(Note: Do not use Tulle or the like because want netting doors to last.)
I used Tulle on my blue single-skin tunnel tent. Still going strong about 10 years later.

Cheers

[Sam Farrington]

Roger, all Tulle’s are not equal.  How much does your Tulle weigh, in oz/yd2 or gm/m2?  I’ve looked at what is available in the US, and it is even more fragile than the netting used on many tents.  Can your Tulle be sourced for sales to the USA?  If so, would appreciate a link to a retailer so I can order and test some.  I’m OK with the idea of using stronger nylon netting, because for inner bug doors, a bit of sag is OK.   Thanks.

[Roger Caffin]

Hi Sam

I imagine you are right: not all fabrics are equal.
The Bridal Tulle I use is about 9.1 g/sqm (gsm) or 0.268 oz/sqyd. That is very light.

The key thing about any very light fabric is the thread used. Many versions of no-see-um netting are 15 – 20 gsm, and some are indeed a bit fragile. Now, look closely at one of those bits of netting and you will see that the thread used in the knitting is made of many very fine filaments. These filaments can snag and break one by one too easily.

But the Bridal Tulle I use is knitted from a single filament – but a much coarser one. It is of course much stronger than the very fine ones in a no-see-um: it has to be if you don’t want it shredding as the bride walks up the aisle! In fact, the single filament is sufficiently strong that it usually resists breakage, slipping over things which might otherwise catch and break the finer filaments.

Yes, over the last 10+ years there have been one or two little snags in the tulle in my blue summer tunnel tent – but only a few. I sew small patches of tulle over the little holes when they happen.

Cheers

[MJ H]

Will magnets, especially strong ones, on your tent door mess up your compass if you have it near there for a whole?

[Roger Caffin]

I don’t think any common magnets will damage the needle in a compass, but I fairly sure they could upset your navigation when the tent (or tarp) is on your back. I did experiment some time ago, and decided that I would not use them.

This is not to say just any magnet will do that, but do you want to be able to trust your compass?

Cheers

[MJ H]

Yes, I do. I have the compass because I learned the awkward way that the needle on a GPS system can be wrong and stay wrong in a forest for a good while.

[Sam Farrington]

Roger, that Tulle you use sounds remarkable.  Unfortunately, nothing like that around here in the shops.  So am limited to the best nylon from USA and European sources.  From them the best netting is still pretty light, but when it has been sewn into an integral part of a tent, would like it to last because it is a bear to replace a netting panel.

Also note that a lot of US tents have netting that is a structural part of the tent because the inner tents use netting panels that are structural, in that they support the tent.  In a simple wedge tent for example.  The ones you call pop-ups.  So I do not use netting for anything structural that must be replaced as soon as it fails.

Lastly, I want the netting to be durable enough to keep out pests.

So using netting that will hold up is important for the above reasons, even if it weighs a bit more.

[Roger Caffin]

The problem with GPS errors is often that the algorithm takes the 1st 3 satellites as gospel, even if they are seriously wrong, and assesses all subsequent satellites against the first 3. If they disagree with the 1st 3, they are rejected!

This is an old problem. I would have thought that the mfrs would have fixed this by now – but if you have an old GPS with the old code . . .

Cheers

[Roger Caffin]

Roger, that Tulle you use sounds remarkable. Unfortunately, nothing like that around here in the shops. So am limited to the best nylon from USA and European sources.
You may be chasing the wrong thing.

If the fabric is advertised as having a soft drape, then the threads are probably multi-filament. They are a lot softer than the single-filament stuff I use. Very suitable for some things of course.

But if it is advertised as being a bit stiff, consider it. In fact, I suspect some ‘Tutu Tulle’ might be suitable as tutus have to flair out. The stiffness has to be intrinsic: you can’t rely on starch for this. There is a lot of this on ebay, very cheaply. Ask the vendor about the thread: single or multi-filament.
If they don’t know what you are talking about, try a different vendor!

Cheers

Hey – how do you fancy Tulle with sequins???

[Sam Farrington]

Not sure that the magnetic discs would be a problem if the magnetism were the only issue.  The tent is behind me in the pack, and the compass is held in front of me.  Ditto with the GPS to record waypoints.  Don’t expect the compass to be totally accurate, just an approximate guide.  It is the topo maps that are much more essential to provide a mental image of the terrain in order to tell me the direction to go, or where “handrailing” can be helpful.  But only the USGS 7.5 minute topos are detailed enough to do that.  For example, National Geo has ruined the Trails Illustrated maps with shading that blocks out detail, including contour lines.   I’d be more concerned about the effects of the discs on GPS devices, if it were so.

[Author]

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