Tag Archives: aquasure

Inflatable kayaks: glue and repairs

Updated Summer 2020

See also: Repairing a Gumotex Seawave
MYO D-rings


It’s understandable to worry that something like an inflatable boat is a bit of a liability when out in the middle of a deep lake, hairing down some shallow white-water or far out to sea. This is especially pertinent if your only experience is a beach toy made of a thin and stretchy PVC film.


I’ve owned over a dozen inflatable boats and have only had one tiny thorn pinprick in the Inceptage-related fabric perforation on the ancient Semperit and a hole worn through carelessness in my Seawave.

It’s hard to think of anything puncturing my full Nitrilon Gumotex IKs or the old Grabner once on the actual water. What more often happens is some kind of accidental wear or rubbing when not paddling or during transportation, like the trolley wheels which wore a hole in my Seawave, or the windy tree branch which rubbed (but did not puncture) my Grabner (left). I also snagged my packraft’s uninflated floor on submerged concrete once, and added protection to the outside and padding on the inside to stop that happening again.

I’ve also travelled with cheap slackrafts that have got ruined within minutes and punctured every other day. You do get what you pay for. So when it comes to glue I’ve learned that preparation and application are vital to getting a good repair: rough it up; wipe it down with solvent, apply the right glue to both surfaces, wait, then slap on the patch and press down hard with roller to achieve a long-lasting bond. More below.


Is your boat plastic or rubber?
As explained here, broadly speaking IKs are made of either rubber- or PVC-coated fabrics. Rubber-based Hypalon, EDPM or Nitrilon is most often used with the tubeless construction method.
On a boat like this, rough up the surface, clean with solvent (see below), apply the right glue and a same-material patch, all which needs to be done well as the patch is vulnerable on the outside. Or, you can just dab some Aquaseal directly onto a small hole in the hull to protect it from wear, as shown above left (not an actual puncture).

One-part glues
I’ve succeeded in gluing on non-critical D-rings onto Nitrilon Gumotex and EDPM Grabner boats using single-part Aquasure sealant/adhesive. Allow it to become touch-dry on both surfaces. Allowing Aquaseal to half-cure in air and then sticking together and letting it ‘seal’ to itself is a way of bonding anything – even non-compatible rubber-based Nitrilon to PVC, as I did here.
Their Seam Grip is a runnier version of Aquaseal to get into cracks and seams. Though I’ve not tried it yet, British-made Stormsure is the same thing.

In the UK you can buy Aqausure in 28g tubes from £6, or 250g for around £24. Unless you have a lot to glue/seal jobs, be wary of saving money with the big, 250-g tube; give it a chance and it’ll split and harden before you get to use it all, even if it’s effectively over half price.


The other one-part glue I used on my PU/PVC Incept IK, Slackrafts and used recently on an old hypalon Semperit is Bostik 1782, not least because it once went real cheap on ebay.


I can’t say it worked that well on my Incept; two-part adhesive is always better. Even on the slackraft the Bostik softened and shrivelled the thin PVC. But on non-critical applications (D-rings and none-huge tears), 1782 seems to work well on hypalon (rubbery hypalon is always easier to glue than plastic PVC) and at £10 for 100ml was good value. Plus it’s a nitrile rubber/resin-based solution and I’ve found won’t go off and harden in the tube like Aquaseal often does. It’s my favourite, do-it-all, one-part glue

One glue I wouldn’t bother with is whatever Gumotex used (still do?) supply with their repair kits: Chemopren Universal (above left). It looks like the brown rubber solution you’d use on a bicycle inner tube. I remember trying to use it on my old Gumotex Sunny years ago and finding it was crap. Back then it may have been me, but I tried to use Chemopren again recently on my hypalon Semperit and it wouldn’t even adhere to a roughed up, MEK’d surface! To be fair it might have been many years old, but so are my other glues.

Actually what came with my Seawave in 2014 is a small tube of ElaStick (above right). But it looks like a generic polyurethane do-it-all glue. It remains unused with the boat and probably will stay that way until it goes off. I’d sooner rely on Nirtile-based 1782 or Aquaseal for field repairs

Two-part glue


For important jobs use much stronger two-part adhesives suited to actually assembling air boats as well as making more permanent fittings and bomb-proof repairs.
At about £15 posted for a 250-mil tin, Polymarine 2990 Hypalon adhesive (left) is much cheaper per ml than Aquaseal or Bostik 1782. In the UK Ribstore and Ribright sell similar stuff (below) just make sure you buy for Hypalon or PVC. I’ve used it to glue D-rings onto my Grabner (more here), floor patches to my Alpacka, latex socks to my dry trousers and patches as well as repairs to my Nitrilon Seawave, It sticks like shit to a s***el.

sempauto - 11

In 2017 when I dismembered an old IK, I was easily able to pull off recent patches glued on with Bostik by hand. But I could only pull off Polymarined patches with a pair of Knipex hydraulic trench pliers and even then, the patch coating pulled away from it’s core (lighter exposed weave below) or the patch remained stuck to the boat and instead pulled off the dead’s boat’s hypalon coating revealing the fabric’s yellowed core or scrim. The two recently glued surfaces could not be separated. They say the mixing of the two components causes a chemical ‘vulcanisation’ and molecular cross-linking which creates a very strong bond. Mixing and applying two-part is a pain, but it works.


Get a good roller


Single or two-part, once you apply your patch, roll it very hard with something like the classic Baltic-pine handled Sealey TST15 stitch roller (left) aka: tyre repair roller used for innertube and tyre repairs. The knurled metal wheel set in a solid handle applies much greater pressure than a wide plastic roller I used to use, and they’re only about a fiver on ebay. Buy one now so you’re ready.


Bladder boat and packraft repairs
With smooth-skinned Alpacka packrafts, they recommend two-inch wide Tyvec adhesive tape produced by DuPont. Just peel off the back and apply a section on to pricks or small tears once the surface has been cleaned and dried. No need for roughing up, but a quick wipe with solvent won’t do any harm. Larger tears can be sewn then taped. Tyvec will work on urethane IK bladders and extra tacky duct tape or gorilla tape will do too, but is unlikely to remain impermeable once immersed for a while.

Aire-style bladder boat repairs are actually easy. According to Aire’s youtube vid, you unzip the hull shell, slap on a bit of Tyvec on the split, tape up the inner side of the hull shell gash to keep out grit, reflate and off you go. You can glue up in the usual way later, if necessary. I had the feeling that on my Feathercraft Java the urethane-coated sponsons made of thin ripstop nylon fabric (like tent flysheet material) couldn’t have been securely repaired with tape. In fact, it would be difficult to bond anything well to the slippery nylon fabric compared to smooth urethane plastic or hypalon-like surfaces, but perhaps once inflated the seal would have been fine.

Good article on how adhesives work

Cleaning solvents


Once you’ve done your roughing up (sandpaper or a foam abrasive sanding block, left) you need to clean off the residue as well as any oil or grease present. Anything will do in a pinch; alcohol and spirits, after-shave or nail polish remover (acetone), lighter fluid, white gas or petrol of course, but not oilier diesel, aviation fuel or Nivea for Men. Bleaching agents aren’t the same thing. In the end just use water to remove the dusty, post-roughing residue, and on a cold day it can help to warm up the damaged surface to cure the glue more quickly.


For a travel repair kit a tin of lighter fluid (same as white gas) or nail polish remover (acetone) are easy to buy and handy to pack. Back at home I’ve found MEK (Methyl Ethyl Ketone) is inexpensive at £9/ltr and hideously effective. Acetone is even cheaper and perhaps less extreme – all we’re really talking about is cleaning off any grease and the dust after sanding.
They say MEK is for PVC boats rather than Hypalon, but on a thin plastic slackraft the PVC will shrivel up before your eyes once MEK’d. Even on rubber-based coatings use MEK or similar toluene sparingly. Expect some colour to come away on the cloth and the coating to soften at bit: good for adhesion. Note the NRS video above specifically recommends toluene (the second ‘T’ in ‘TNT’ explosive, fyi) for hypalon. On ebay uk it’s the same £9/ltr but they won’t post this stuff around the USA.

Huge tears and bear bites

semp- - 3

If you have a huge gash, as in the folding Klepper’s hull below, sewing is the only way to contain the tear when applied to an IK. Then apply a huge patch with adhesive, as normal. The boat below caught a cut-down metal fence stake buried in a shallow river bed and was actually sent back to Klepper for professional repair. It’s tempting to think an IK’s pressurised hull would have skimmed over the stake rather than snagged it. The smaller 1-inch L-tear on the left was glued with a 5-inch patch but the 30-year0old IK proved to be totalled.


Incept K40 Tasman inflatable kayak review

What’s in the bag?
The other night I tipped out the contents of the blue bag and unrolled the boat from a factory-packed volume which, like a new Alpacka, it’s never likely to regain (see below in red). It all added up to:

  • Blue roll top dry bag
  • Boat with deck lines and all rudder controls/lines
  • Rudder assembly
  • Flexible hatch coaming rod
  • Inflatable seat
  • Four GRP battens which slip into the deck to give it form
  • K-Pump in a bag with adaptors and grease
  • Boat repair kit (glue, a dozen patches and a valve adaptor, see red)
  • Basic instructions and an NZ leaflet on safe sea kayaking

What’s not in the bag – a spray deck. You get the impression that it’s a special shape/item and so ought to be included, but I’m told it’s €103 euros for the one Incept recommend. It’s hard to ascertain exactly what you’re buying from the small image buried on their website; looks like a nylon tunnel/neoprene deck ‘n’ braces jobbie which go for around half that price in the UK. Never needed a deck before and doing a bit of research it seems nylon looks cheap, but is more comfy and versatile for rec touring; and also for a touring boat the K40 has a relatively small but otherwise normal hatch – it’s more or less the ‘Low Volume’ profile. I may end up with one of those ChillCheater Aquatherms if the cheapie I just bought and gave a quick 8-inch Caesarian (above left) proves to be crap. It’s actually not badly made for 19 quid, with taped seams and a decent coated material; it’s just way too long.
As it is, a K40’s sides sit a lot higher than a regular hardshell kayak, so I imagine a skirt would only be necessary when it gets really rough (by which time you probably have other issues) or cold, or you confidently expect to be able to extract yourself from capsizing with one smooth swipe of your blade. It would be nice to master a roll, but I suspect that crawling back into a K40 with decks unzipped is less difficult, especially with a paddle float. More on that here.
Hatch size by the way is 71cm long, 41cm wide and 186cm circumference (28″ x 16″ x 73″), if that helps you select a spray deck. Although it’s statistically small, I’ve sat in worse and as it’s not rigid, even I can pull my legs up to get out while still seated.
Also, no thigh straps which are standard on a Gumotex Safari and Feathercraft Java, but are another €66 option. Fair enough, but my boat has no D-rings patches (left, Incept’s pic) glued to the inside for the straps, although my hull has markings where to fix them. Some boats get patches, some don’t I was informed, so if ordering make sure your boat has some in place (probably welded, as in the red pic above left), otherwise it’s a lot messy work glueing some on (below left), which will either cost you over £50 for four Incept patches sent over from NZ (half that price being postage!?). Or you can spend hours on the internet looking for alternatives with more reasonable postage rates. I fretted for a while thinking I must buy actual Incept ones which are made from the same PVC-urethane material as the hull. As well as clean surfaces and a good roller, on inflatables the adhesive/material combination is critical for a good, permanent seal. The actual Incept PVC patches cost $NZ12, similar to the UK from places like PolyMarine or this place. Or good old NRS have all sorts of patches here and among other places, they now have an outlet in Ireland (so all import taxes paid). I bought a dozen #2097s (as pictured above right) which are a bit big at nearly 5″ (120mm) but can be trimmed. NRS said that Aquaseal (aka: Aquasure in Europe) will do the job on PVC-to-PVC as well as anything, but actually one D-ring stuck on with Aquaseal came off three times. Could have been my bad application so eventually I tried the small unbranded tube of Ultraseal 777 which came with the boat’s repair kit. It’s a much thinner and runnier than Aquaseal and smells like classic Bostik, and because it was not ‘filling’ but just adhering, I thought it made a much better, more pliant seal and it cured quickly too. I’ll find out for sure how the 777 patches worked in comparison with the Aquaseal in Australia. Unfortunately, though it’s made by Bostik, you can only buy tins of it in NZ or Australia, as far as I can tell, and shiiping by air seems a problem (as it is with some glues sold in the US). I couldn’t divine whether 777 has a magical formula that perfectly suits Incepts polyurethane alloy fabric, but in future I’ll clean off with MEK solvent and use something called Bostik 1782 – the nearest I could guess and found cheap on ebay.
While my back was turned Bostik seem to have diversified into scores of glues from my youth when the classic, pink-tubed all-purpose glue did it all. Now they sell a glue for scores of uses which the cynical consumer can’t help thinking is marketing- rather than function led. It includes the tiny green overpriced tubes for Soft Plastics (left) that’s also water resistant, but you can’t help thinking it’s just the same old stuff in a different packet.
The Seakayakoban test boat I tried had thigh straps (it had a spray deck too, but I didn’t bother even looking at it as it was so calm that day) and although these straps are straight and not as comfortable as the pre-curved ones I recall having on a Java or Safari, they’re a great idea in principle. Pre-curved straps hook better over the knees, so I got a pair off amazon for £33 as recommended for any SoT kayak (above right). With those brass-plated clippy things they’re heavy, but seeing as they’re so fat they may well double up as cushier backpacking straps on the Watershed UDB or a boat hauling packframe. Or the other way round – the thin but light UDB straps can double up as thigh straps to save weight on tour. It gets better; it’s just occurred to me that the adjustable holdall straps off my smaller Watershed Chattooga (right) or any big holdall for that matter, would make adequate and much lighter thigh straps.
One more annoyance – I was expecting to get the cheapo Bravo pump (as comes with Gumboats) which the shop I bought it from pictured and confirmed by email, but I actually received the better K-Pump after I went out of my way and bought another for $70 in the US. This inconsistency with Incept’s info (including images of models with old colour schemes, velcro decks and talk of ’25 D-ring attachment points’ in current brochures) gets frustrating. You get the feeling Incept aren’t fully focussing on promoting these IKs (they make a tandem K50 too) as if they’re a sideline to the raft business. But as long as the people on the factory floor with the scissors and heat guns are on the ball, I’m sure I’ll get over it.

According to my measuring instruments, the boat alone weighs 14.8kg + 2.2kg for rudder, seat, repair kit and pump. And it’s 4.3m long, up to 69cm beam and up to 45cm wide inside (32.6lb + 4.8lb; 14′ 1″; 27″; 18″). I have seen claimed weights as low as 15kg, as well as greater length and less width listed on other sources.
The table from this post compares actual dimensions (where known) or official stats on similar IKs, including the Tasman. At 17kg it actually feels pretty light and as long as it’s empty, not too windy and the path is easy, I can carry the kayak on my head or the back of my shoulders to and from the water.

Quality of construction is pretty poor; not as good as a Gumotex or Grabner. Most of the boat is heat-welded. Closer inspection of mine found a lifted seam at the glued-on rudder patch (above left). The cavity here was an inch deep and took repeated injections of Aquaseal to fill, but I presume this is a patch glued on the hull, otherwise I’d have a pretty flaccid boat. Nearby, a couple of hull seams had also lifted a mil or two (middle pic). It’s hard to think these would have slipped past an inspection (assuming there is one), so I presume they lifted after that point. These are the only manufacturing flaws I’ve spotted on an otherwise clean job. And to be fair the rudder patch glues round a curve where two other layers meet, so it’s a difficult join. I’ve laddled the whole area with Aquaseal (last pic) and it’s now sealed for good.
Incepts are made from 1100 dtex Polyester fabric coated in a PVC-urethane blend rather than rubber-like Hypalon or Nitrilon. It’s notably less thick than an old-style Gumotex, but some might say they were a bit over the top anyway in terms of durability. Stiffer is harder to glue in tight forms (as proved above) but makes a much faster boat on the water. It’s also a bit more awkward to pack down well, especially when it’s cold. I can’t see me ever rolling it up as compact as the image at the top of the page (see red text , below). I go on further about IK materials here and as always, theboatpeople speak sagely about Incept sea kayaks here, though it’s unclear if they’ve actually seen one in the raw (never stopped me on this blog!). Note what TBP say about Incept’s PVC-urethane alloy being better than straight PVC.
As the enclosed instructions say, the biggest risk to damaging a PVC craft is when a sharp and stiff corner of a rolled up boat scrapes on concrete or tarmac; it grinds off the coating real quick. Must remember never to do that. It’s unlikely that the PVC-U is as durable as more expensive synthetic rubbers like Nitrilon or Grabner’s EPDM, but with care, regular rinsing, squirts of 303 and the odd dab of glue, it should last. In fact the K40 is the only IK I’ve ever punctured – just a tiny thorn tip picked up when pumping up. The second owners similarly punctured the side while pushed into past a thorn three on a river and again at sea later. Knowing all this in retrospect I would say Incept’s choice of fabric for the K40 may have been too thin, but the only other owner of an older red and yellow boat has had no problems at all.
Out of the bag I pumped it up for the night and fitted and adjusted the rudder which was dead easy. Next morning all was still pleasingly firm, so off to one of the local lochs. Down on a small beach near a road, again I was surprised how effortlessly the K-Pump inflated the K’s three chambers until the PRVs start hissing at 5 psi or 0.34 bar – has high as any regular IK. I like the idea that on the water you’re able to top up the pump from inside the cockpit as all the valves are located accessibly by your lap, though over the course of that warm day – leaving it in the sun here, there and on the car’s roof – it wasn’t necessary. And I sure like the fact that the Halkey Roberts’ valve caps (left) twist off easily and back on securely, unlike my old Sunny’s horribly stiff and awkward items which never relented in all years or use.

Packing up a Tasman
As mentioned, the stiff PVC which responds so well on the water makes rolling and packing a K40 a bit of a challenge, especially if space is important like getting on transportation and it’s not warm. After a few weeks of ownership I finally gave it a go. First thing to do is the suck all the air out that you can’t do by just rolling; this is something a K-Pump does not claim to do (despite what you may read), but I’ve only lately discovered a Bravo pump (left) can do once you switch the hose to the other port from the one pictured. With the Halkey valve opened (pressed down) the spring in the Bravo’s bellows sucks stoically until you can hear the PVC creaking. All you have to do then is yank off the push-fit hose and close the valve quick against the boat’s partial vacuum – tricky with fingers; you may need pliers. Looking again at the Bravo pump I’ve used for years with my Gumboats, it’s not such a bad or heavy pump at less than half the price of a K-Pump (where you can buy it). But I know it won’t be long before first the hose and then the bellows splits (though both are easily repairable with duct tape). The ABS K-Pump is heavier and as bulky in its own way, but it’s more robust and for a hand pump is amazingly effortless. The K is the pump to use even if it doesn’t suck, but the boat comes with a bayonet valve adaptor in the spares kit (not a spare valve core as I thought). Pop that on a short length of hose and you have a manual – or oral – sucking tube (above  right) to compact the K40 for transit. If this is all TMI, just say ;-)

First impressions on the water were a bit shaky compared to the test day a few weeks back when conditions were about the same if not even calmer. Maybe because I was alone, ill-dressed for the very cold water, and the valley caught the odd gust off the big mountain (left). I’ve been back since in the packraft and this place may indeed be a bit of a wind trap, though it sure looks good. Who knows what was up, but I doddered around like a beginner, then parked up on another beach (left) for a walkabout, and on the way back paddled with the deck unrolled which was fun, just like a Sunny, but faster and much yellower. Just as it is on an Alpacka, this convertible deck arrangement is such a great idea,. It’s like owning a brolly or a mac – you don’t always want it but sometimes you need it.
Part of the reason deck-free is possible is that the K uses a removable bendy nylon rod for the hatch rim or coaming (above right; the inset shows it closed up). It’s designed to be removable for compact packing, but for paddling it means you can pull out the flexy rod with the black string loop, remove the four chunky GRP deck-forming battens, roll the deck back to the right side (clip the seat mount through the hatch hole, with another easily fitted tape will help to keep it off your feet) and hey presto the legs can breath, you can get in and out gracefully and maybe even carry a light passenger sitting behind you facing backwards. Though thick and strong, the battens don’t seem to have any influence on pushing the boat’s sides out as far as I could tell, it’s more likely a zipped up deck holds the sides in if anything, so inhibiting longitudinal flex of the hull in rough conditions with a heavy paddler. Looks to me like the battens are just there to give the deck some convex profile to stop pooling. If one broke or got lost I imagine you could trim a branch or some such.
The rudder mounts easily and looks like a well made unit, though again, I’m no expert. Foot control is off some flaps on an adjustable air bag footrest using strings and elastic. It’s all a bit mushy, but I don’t think any IK or even any K will have a system as solid as the Amoco Cadiz. It centres naturally and so works fine as a simple straight tracking skeg which is all you want most of the time. For an impression of rudder free paddling, read this. One thing I’ve learned is lift the rudder in the shallows to save damaging the mount.
If you want to slide forward down the boat (perhaps to pull the deck on or have a snooze) you can easily slip your feet under the semi-inflated footrest/rudder pedal air bag. Turning circle on full rudder lock is about 10 metres, same as our Nissan, and I also observed that you can do a 360 in this boat on the spot with 5 back strokes; in other words easier and less strokes than you’d imagine. Backing up is also easy with the rudder up and the rudder lift thing works fine. A rudder of course came into it’s own to correct tracking when paddling downwind or at 45° to the wind in either direction, though here is where the mushiness was noticeable. To be fair, a bit more experimentation with the footrest/rudder pedal air bag pressures and seating/footrest positions may tighten things up.
So far the seat is fine and I’ve had no complaints since. It’s light and simple, but made from chunky nylon (compared to an Alpacka) with two elbow valves – and it clips out in seconds, just like the modified seat in my old Sunny. But like on my old Alpacka Llama, you sometimes sit on the squashed down backrest when getting in with the deck on, which could be a pain if the situation was choppy or awkward. There is more back support with the deck on I’ve found, as you lean on the back coaming a bit. I’ve also since found even at sea it’s safe and stable to sit sideways on the seat with your feet in the water – good for fishing perhaps.
nk4-carBy the time I got back a couple of hours later I was in the mood for more so I strapped the boat onto the car (another great aspect of frameless IKs) and scooted over to the main beach opposite the Isles. That morning there’d been no less than nine cars or vans with kayak racks heading out for the day. Quite right too as it was amazing weather here then, so much so that the blooming gorse in the hills caught fire. As I came back, the village fire engine dashed past me, trailing cobwebs and heading for the smoke palling over the Assynt to the north.
Out in the bay a pair of late hardshellers were heading out (left), and it seemed a bit less gust prone out in the open water. After dicking about for a bit, I dared myself to head out to a pink buoy and once there and still breathing thought heck, let’s go right across to Tanera Mor island, about two miles across the long reach. I look over to Tanera all day from our place, and on many previous occasions in the Sunny I’ve thought about it but never dared, even though in the conditions that day it would have been technically easy. I suspect the relative speed and higher sides of the Incept gave me the edge and the confidence.
In the island’s anchorage, flushed with the success of my monumental traverse from the mainland of Britain, I pulled over by a salmon pen and watched the caged fish flit across the surface, I presume enacting their instinctive upstream spawning surge, but here destined only for the slicer and the smokehouse. On the way back I decided to deck up for no other reason than I could, noting that when fully unzipped, I can just about reach the zip ends fore and aft to pull them closed, as long as I used the fishpen side for stability. Out at sea if it was rough a boat alongside would be needed, or a paddle float or a short hook stick. I’ve since lengthened the tabs on the zip ends to make them more reachable.
A small island ferry left the nearby jetty at the same time as me, and mid-crossing its parallel wake crept ever closer until at the last minute I panicked a bit and turned into it to be on the safe side as I wasn’t sure how the wide, flat Tasman might react to side waves. Later a bigger fishing boat came across my bows leaving a bigger wake which of course was no bother if not rather fun taken side on. I’ve since found the K40 is fine in side waves that can make a slinky hardshell a little nervous.
No GPS but I timed myself; 25 mins to cover 2 miles which were a bit choppier than on the way out. That’s 7.2kph or 4.5mph or 3.9 knots if you must. Not bad at all and it all rather neatly validates exactly what I ruminated on earlier about getting a better boat for my time up here: dashing alone across what I would classify as ‘open’ water was one of the main reasons I wanted a faster, decked IK. The Incept has delivered on Day 1.
The gallery below includes some other images from the day, including a mod I’ve made to my Kokatat pfd to carry a 2.5-litre bladder (spotted something similar in a shop). So much handier than having a water bottle knocking about between your legs.