Tag Archives: tizip

MYOG: TiZip Pakbag

See also:
Deck bags for packboats

As mentioned here, wafting down the Tarn Gorge one summer with a Watershed Chattooga drybag jammed under my knees gave me plenty of time to configure a ‘deckbag’ to better fit my needs.


Peli cases are too heavy and cumbersome for these sorts of trips, while dependably dunk-proof – or even submersible bags like the Chattooga are too big and too fiddly to seal easily (since replaced with an Ortlieb Travel Zip). All I needed a 5-litre bag to sit on the floor below my knees for my must-stay-dries.
Using state-of-the-art Adobe Crayon™ CAD software I came up with a design (above) and optimal dims of about 29cm x 15cm wide by 12cm deep giving about 5 litres volume. Part of the attraction of this project was learning to heat-weld TPU fabric with a small iron. It looks so much easier and less messy than glue. Or so I thought.

Before I got – quite literally – stuck in, I considered adapting some of the many heavy-duty SealLine PVC roll-top dry bags I have knocking about. All I needed to do was stick a zip in, then somehow cap one end with a round piece of something. I may well try that later but what I was actually aiming for was a stable box not a cylinder to sit securely on the floor of a boat.

Heat welding: important to understand
PVC plastic can’t be heat sealed with an iron because it’s double coated. With double-coated anything (TPU, PVC, etc) the hot iron will easily melt the coating and make a right mess. Done this way you need to use a heat gun and a roller (left) which requires three hands. Or use single-sided PVC seam tape. Or of course, use glue.

The body of my Pakbag could be made from single-coated yellow 210D packraft hull fabric, with the near-square end panels in ‘both-sides-coated’ 420D black packraft floor material. At 650g/sqm (27oz/sq yard) this stuff is good and thick. The thin yellow is 275g/sqm.


Half a metre minimum order of each cost €10 and €20 respectively from extremtextil in Germany; a very handy resource for the home fabrician. What you see left is what’s left over. Extrem were also one of the only places I found who’d sell a couple of 23-cm TiZip MasterSeal 10s for €23 each. Rolled delivery cost a bit more but avoided folds and was very fast. In the meantime I bought a used Prolux iron off ebay for 20 quid and already had some scissors, a table, a ruler and a knife.


I’m not so skilled at home handicrafts so expected to make a right mess of things first time round, and was prepared to make a second bag. The next best thing I could do was think carefully before diving in like Edward Scissorhands at a confetti convention.
One smart decision I made was to use a wooden mould to form the bag around. I could have laboriously hand-sawn some kitchen-shelf leftovers down to size, but after more ebaying found a pair of hobbyist’s knick-knack balsa boxes which added up to 15 x 12 x 30 stacked.
As mentioned, you can’t iron on the coated side of TPU fabric; the coating will melt all over your iron before it bonds to whatever’s underneath. You can only directly heat an uncoated surface while pressing down the coated side which melts to the corresponding panel – coated or uncoated.


You can learn a lot from the DIY Packraft website. Lord knows how these guys manage to make packrafts from a roll of raw TPU. There can be no doubt that my attempt would end up looking like Picasso in an abattoir, but a dinky, curve-free pakbag ought to be within my abilities.


They mention the need for an iron with an adequate and consistent spread of heat up to around 220°C. Rated at 205°C, my cheapo Prolux was not in this category. I understand model makers find them ideal for applying thin transfers. For TPU work you need an iron with more poke, costing at least three times as much.
I practised joining 210D to 210D, but sealing was far from instantaneously miraculous. It took repeated ironing and pressing, as well as spot heating to get a full seal with virtually no air gaps or lifted edges. You could then peel it apart if you got an edge up, but you certainly couldn’t pull it apart. I thought maybe the coating may be too thin or once melted was gone for good, but it’s probably just my crap iron.

For the end panels you need to seal 210D on to the thick black 420D. The box mould really helped to make a neat-enough job. One interesting observation about joining fabrics by sewing or heat-welding is that millimetre-precise measurements aren’t critical as they are with wood or metal. I took more time than I needed cutting the exact forms and trying to get precisely perpendicular edges. A big metal set square may help, or you can find stuff round the house – in my case, some square glass bathroom scales. Another tip is arrange something sticky under your cutting edge ruler so it doesn’t slip as you slice hard to get a full, straight cut.


The length of the bag is partly governed by the available zip size. The 23cm MS10 Tizip which extrem sell is presumably used as a relief zip on men’s drysuits, but for a bag has a minimally useful aperture of just 19cm. The next size they sell is a massive 71cm. They must make TiZip sizes in between (for example for packraft cargo hulls), but good luck tracking them down online.

First job was wrapping the bag body panel round the box mould and sealing it. Cue endless to and fro with the iron to try and get a complete seal before I gave up and accepted I’d glue up the gaps later.  Looking back, I should have made this join on the top of the bag, either side of the zip. Barely two inches of yellow to yellow sealing required here. Now I know.
I dropped a black end panel on to the end of the box mould.
and welded down the bits between the corners.
Then I made an incision at each corner, pressed the flaps down over each other and welded on. Good to know the 210 welds much better to the thicker coated black stuff.
Sealing wasn’t perfect but all along I expected to have to hand seal all joins, and certainly all corners with Seam Seal.
Before sealing the other end, I cut a slot for the zip.
Then ironed it down. Again, the thick coating on the broad zip sides made good adhesion easier to achieve.
I stuck a home-made D-ring on the finished end. I actually needed this to pull the bag off the tightly fitting box mould before doing the other end. This requires sawing an end off the box so it can be removed through the zip hole after butting up against the unfinished bag end to support firm heat welding.
Oh dear, look at the state of that floor seal inside the bag. I went over it again with the iron, then filled up the gaps with glue.
Then I stuck the zip cut-out over it for good measure. Once inverted, I did the same on the outside for more good measure. It’s not pretty but it ought to seal.
With the bag still inside out, I went round the yellow-to-black joins with Seam Seal. It’s like Aquasure/Aquaseal, but runnier and takes a long time to dry.
Beautifully sealed seams. I should get a job at Alpacka.
The bag turned right way out. I’m amazed that it looks less crap than I  expected. No need for stiffeners; as hoped, the 420 end panels retain the boxy shape. The box mould (sawn off bits in the foreground) helped greatly in making a tidy form.
Without the strap the bag weighs 158g or 5.5 oz.
Completed Pakbag alongside the Aquapac and a Peli 1150.
Pakbag, with a foam floor panel to keep above any moisture. A sachet of silica crystals may help humidity, as does TiZip silicon lube for the zip end. It passed the submersion sink test.

Several features are omitted from the Adobe Crayon blueprint at the top of the page:

• The overlap sleeve on the side to contain the shoulder strap to avoid entrapment. On rough water I’ll just unhook the shoulder strap and stash it

• Otherwise the full-length shoulder strap can adjust down to ‘handbag ‘length so there’s less is lying about

• No side net. Would still quite like this but not sure how to do it neatly

• TiZip is not diagonal – not important –dripbox but the arched stays idea underneath it may be. I noticed in France under the knees gets a lot of drips off the paddle (PSZ; right) which can get in when you open up.
Convex top would be good but a shake of the bag may thrown off excess drips before unzipping

• Need to find a way to attach it to the packraft floor. Velcro might be low profile but with the repeated force of pulling apart, I’m not sure the shiny-backed stuff I have will glue to the bag or the floor well enough, even with proper two-part glue. So Ill just clip one of the strap rings a D-ring glued on, mid-floor

A few months later… using the Pakbag


After paddling the Wairoa River in New Zealand as a day trip, I can boldly claim my MYO Pakbag is fit for purpose. It’s just the right size for a water bootle, camera, GPS and wallet, even if the easy-to-use zip is a tad short for easy access.
One thing I didn’t appreciate is that, slung over the shoulder while sat in the boat, the bag is still handy to access but keeps off a wet floor and is always attached to you. No need to think where it is.

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Sadly my glue or gluing skills are not so fit for purpose. I need to reglue the strap end-rings and a couple of corners. This time I’ll probably use 2-part glue which I know will tear off the coating from the fabric core before it separates from what it’s glued to.

What I’d really like is for someone to make this properly. The difficulty – as possibly mentioned above – seems to be that anything with TiZips requires the consent and approval of TiZip Inc before they supply a zip. It’s a way of ensuring a proper application to their tight specs is done so that their reputation is not harmed. Which is why many TiZip products, like my Ortlieb Travel Zip bag are unusually expensive. You’d think there must be alternative or knock-off TiZips around; I’m pretty sure I searched and searched.

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Deckbags for packboats

See also:
Anfibio DeckPack
MYOG TiZip Pakbag


Whether on day trips or overnighters, how do you organise easy access to regularly used items and valuables, including stuff you want to carry when away from your packboat? I’m talking something capable of handling less than flat water, rated at least IP65 (right) to stash the wallet, phone, tablet, camera, travel docs, ammo and snacks. Stuff you want to keep dry in case of swamping or capsize, as well as being easy to get to on the water.

For walking or cycling, a daypack does the trick but that doesn’t really work in a paddle boat. The pockets and pouches in your pfd (right) have their uses, but they’re not waterproof. You want something that’s airtight when briefly submerged while easy to access on the water and portable off it. It’s actually quite a tall order.

mapcaseThings like paper maps and nav aids (GPS, compass) I keep in a separate waterproof pouch like the SealLine (left) with a double ziploc seal, even if this is yet more clutter knocking about around your legs.
Since I took that photo I’ve mounted a compass on the side of my Seawave IK – drum-comp very handy as it’s always there at a glance.
And I now use a IPX7-rated Garmin Montana with loads of mapping space, though I prefer to keep salty seawater off it where possible.

Waterproof waist bags
A small, roll-top waterproof waistpack actually ticks many boxes as long as you don’t mind being attached to yet more clobber. There are quite a few out there between 2 and 6 litres, from OverBoard (2 sizes) to Aquapac and the bigger SealLine. The good thing is a waistpack sits up on your lap, out of the water and the paddle splash zone (PSZ), but well within reach.


The bad thing is they’re a faff to roll up and clip down quickly and reliably, and if you’re bobbing around in the water swimming after your boat you can be sure they’ll slowly leak. Read reviews and you’ll come across disgruntled accounts of ruined cameras or phones following a quick dip or even too much splashing. The problem, as usual, is the roll top; it needs to be tightly rolled down 2 or 3 times, then tightly clipped and even cinched down to the sides to make a good, dunk-proof seal. I believe a lot also depends on the nature of those sealing surfaces. As long as you avoid creases, smooth, shiny vinyl or PU pressing against the same will make a better seal than anything textured, like Cordura.


Hard cases
For years the obvious solution seemed to be small ABS or polypropylene hard cases commonly used for camera gear. I started years ago with a 9-litre Otterbox in my Gumotex Sunny days (left). The Otter was lighter and cheaper than the well-known Peli cases, and with either, you know the box will be airtight, access quick enough and boxes make a handy solid footrest in an IK as well as a seat or raised surface on a beach.


After some years I changed to a Peli 1400, a bit less volume than the Otter, but a bit wider and flatter. Adding some retaining straps my Macbook Air fits neatly inside the lid (right), and below there’s room for everything I need in a day.


The only thing that spoils the Peli and similar boxes are the clamps which are hard to open or close effortlessly. Some sort of lever-arch mechanism would be better. Because of this I use the box less often than I would during a paddle. On top of that, a shoulder strap for hands-free carrying is awkward unless attachment rings are added. And at 2 kilos the 1400 is a bit hefty.


I really don’t need a PeliCase’s crush-proof ruggedness. All I want is submersion-proof airtightness up IP65 for which a lunchbox (right) or food storage box might do as well, as long as the durability and seal could be relied on.


Around the same time I got into packrafts I discovered Watershed dry bags. Most of them use an oversized rubbery zip-loc seal which is submersion-proof and therefore miles better than roll-tops. The yellow, 30-litre Chattooga (left) was also more chuckable than a hard case, made a good pillow, and for me had secondary uses for biking. It fits under the knees just about, but as many find, can be difficult to open and close. To operate smoothly and seal quickly the big seal needs lubing with 404 or silicon grease.

I finally got tired of my Chattooga’s tedious seal-closure and got a (now discontinued) Ortlieb Travel Zip (below left) for £100. It has has proved to be a perfect daybag, also at 30 litres. I’ve used this packrafting in New Zealand, motorbiking in Morocco and paddling in Sardinia. The TiZip sees to immersions and two outside mesh-zip pockets make easy access to things that can get wet. Inside are a couple of zip pockets and the carry straps come together with the clever and comfortable hard plastic handle. Add a comfy shoulder strap with a pad and you’re good to go.
They seem to replaced it with a ‘40L‘ version (right) with backpack straps, but it seems to have the same dimensions as mine and so will be as good.


Camera Bags
If you’re serious about paddling photos, get the best waterproof camera you can afford, like the Lumix FT7 – right – £400, or an Olympus TG5 Tough (left). You need a good one because the tiny lens must work within the housing so low-end ones are only OK while the light is good. Occasionally they’ll expose perfectly, but don’t bother the optical zoom beyond halfway unless it’s Elvis galloping on a unicorn.
Any shots on this website from 2019 on, like this story, are shot with the Olympus. You can see the difference. Get one of these cameras and the whole section below on waterproof camera bags becomes irrelevant.


With a regular camera which I’ve also used, you need reliable water protection. I bought a used Aquapac camera bag (left). They’re just your usual roll down and clip jobbies, but inside the lid is a ziploc seal (right) which makes the bag much more dunk-proof than regular roll tops. Testing in a sink, bubbles only escape very slowly, but treading water with it attached to your waist might not end so well.


One flaw with these Aquapac camera bags are the flimsy belt loops. On mine I glued over one with a big tabbed patch (right). But really it’s too bulky to hang off a belt; I ziptie mine into one of the net pouches of my Anfibio Buoy Boy pdf, but only fold over and clip down when at sea. To properly close the seal is too much faffing and usually unnecessary – until it is.

dunkboxsubmarineDoing a sink submersion test (right) reminds you of the difference between hard cases and sealed bags. A rigid box is unaffected by the increased pressure of light submersion. If anything, the pressure forces the lid down on the seal even more.
With a bag it’s the opposite: even a few inches underwater compresses the bag, forcing the air out through any weak point, usually the closure. This is why submarines are made of steel, not PVC fabric.


On the Tarn I found the Chattooga under my knees too big in general, and too big to exit the boat easily (or in a rush). But I sure didn’t miss lugging the hefty Peli 1400 around.
I thought a lot about my needs and for the Allier came up with an interim solution: a smaller 1150-like hardcase (left) of about 2 litres volume for my essentials, including the LX. It worked OK, bar the usual easy opening issues.
I knew from the Tarn what I really wanted was a small waterproof under-knee ‘deckbag’ with a waterproof zip closure. The zip eliminates the bulk as well as dunking unreliability of roll-tops, while the bag weighs much less than a box and carries effortlessly and comfortably on a shoulder strap. I had the dimensions and design all jotted down in my head and eventually made one because…


Waterproof TiZip bags
A lot of Googling later I realised no one makes such a thing. There are plenty of TiZip daypacks like the Lowepro Dryzone range, or larger, watersports-oriented duffles from the likes of Ortlieb or Aire (Frodo; right) or SealLine, which resemble my own YKK-zipped Watershed UDB – one of my favourite bags. But none of the above are smaller than my 30-litre Chattooga.


The closest candidates I’ve found include the IP67-rated Ortlieb Trunk Bag (right and left). At 8 litres it’s a bit on the big side (add up the claimed dims and it’s more like 11 litres). And these days it only comes with a fitting mechanism to lock it to a bike rack. Very clever but this all helps raise the weight to over a kilo and price up to £98. The fabric is also not your usual pliant and mildly carcinogenic Ortlieb PVC, but resembles Heavalon (with its distinctive hexagon patterning) which Gumotex use as decking on some boats.

The Trunk-Bag could suit a lot of paddlers but as it’s made for bikes, you do wonder if it’s actually dunk-proof. Tellingly, the product description says underwater resistance: ‘lower edge of product, duration: 30 mins‘. As well all know, it’s common to be paddling a packraft with a little water swilling around the floor, so unless you slaver the base of your Trunk-Bag in Aquaseal, water will slowly seep through. Not good.


You’d imagine fly fishing waist bags, are ready for dunking. But they’re so large they often came with an added shoulder or neck harness to help take the weight. Plus it seems fly fishing gear may be to outdoor gear like smoked salmon is to fish fingers – prices are nuts. Patagonia make the Stormfront (left), a 10-litre waistpack with an added shoulder strap – yours for as little as £180! It’s just a dunking PVC handbag with a zip!

You’ll find any number of other fly fishing roll-top bags at twice the price of hiking or SUPing examples pictured above.
Note that many find waterproof zips like the plastic TiZip or brass YKK stiff to operate, just as they are on a dry suit. Ideally, you need a good T-toggle and some sort of tab to pull against. And I do wonder if incorporating TiZips to the required standards explains the high prices for gear using them. The full range of TiZips is not readily sold to consumers, only to manufacturers for products which use them.
Anyway, long story long, I decided it might be fun to make my own TiZip deck bag. Read about that here.