Tag Archives: aquaseal

Inflatable Kayaks: Glue & Repairs

See also:
Repairing a Gumotex Seawave
Repairing a huge rip
MYO D-rings
MYO alternative to D-rings

gluerepairs

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 white-water or when 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 an ancient Semperit and a hole worn through careless transportation in my Seawave.

rep-hull

Once on the actual water it’s hard to think of anything actually puncturing my full Nitrilon Gumotex IKs or the old Grabner. 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, then 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.

pvc-or-hypalon

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 much less used now and most 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 and EDPM (Grabner), as well as PVC to Nitrilon using single-part Aquasure urethane sealant/adhesive (‘Aquaseal
‘ in North America). Allowing Aquasure or similar to half-cure in air for 30 minutes, 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. SeamGrip is a runnier version of Aquasure to get into cracks and seams. Though I’ve not tried it yet, British-made Stormsure is the same thing.
Apply a thin film of Aquasure to both surfaces; wait half an hour, then bond with all you’ve got.

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. Alternatively, I’m told a good tip is to store it in the freezer once opened.

sempoe

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.

glue-dring

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 hypalons (rubber 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.

For years Gumotex supplied rubbish Chemopren Universal gluing in their repair kits. It looked like the brown rubber solution you’d use on a bicycle inner tube. I tried to use it on my Gumotex Sunny years ago and found 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.

The glue that came with my second Seawave in 2020 was a small tube of Elastick (left). It looks like a generic polyurethane do-it-all glue, like Aquasure. It will probably remain unused with the boat until it turns solid. I’d sooner rely on Nirtile-based 1782 or Aquasure for field repairs.
Tbe problem with these urethane glues is once you open them or the alloy casing cracks they dry up and harden.

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 is much cheaper per ml than Aquaseal or Bostik 1782. In the UK Ribstore and Ribright sell similar stuff, and Bostik 2402 is the same but prices vary wildly. 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 and Sunny. It sticks like shit to a s***el.

The trick is to measure out the correct quantity. Above: the small bowl about half full of glue and hardener – about 10cc or 2 tablespoons? – was enough to fit two 80mm D-rings. Each surface: the back of the Ds and the hull, need two applications half an hour apart.

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.

semp-glue

Get a good roller

sealey

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.

glu-tyvec

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 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.

On this Sevylor it was the green envelope which ripped a metre long on the second outing! The owned may have over-inflated on a hot day – it only runs 1-1.5psi. The envelope is just a nylon fabric shell so would be an easily sewn repair. Usually it’s the inserted bladders which go. They can be patched.

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

foamdandingblock

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.

toluene
Tri Nitro Toluene (TNT)

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-year-old 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

Dimensions
According to my atomically calibrated measuring instruments, the boat alone weighs 14.8kg + 2.2kg for rudder, seat, repair kit and pump. It’s 4.3m long, 69cm wide and 45cm wide inside (32.6 lb + 4.8 lb; 14′ 1″; 27″; 18″).
The table from this post compares dimensions on similar IKs. At 17kg the K40 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.

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, but similar skirts go for around half that price in the UK. I bought a nylon cheapie to be getting on with. It’s actually not badly made for 19 quid, with taped seams and a decent coated material; it’s just way too long, so I had to cut it down.

Aa K40 sits 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.

The hatch 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.

Thigh straps are a €66 option. Fair enough, but my boat has no D-rings (left, Incept’s pic) for the straps, just markings where to fix them. Some boats get patches, some don’t I was informed (probably heat-welded, left).
Otherwise it’s a lot messy work gluing some on (below left), which will either cost you over £50 for four Incept patches sent over from NZ. Or you can spend hours on the internet looking for alternatives. I fretted, 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 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 (until Brexit happened).

I bought a dozen #2097s (left) 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.
Probably 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 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.
Unfortunately, though it’s made by Bostik, 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 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.

The SeakayakOban test boat I tried had thigh straps – straight, not as comfortable as pre-curved ones I recall having on other IKs.
Pre-curved straps hook better over the knees, so I got a pair for an SoT off amazon for £33 (left). With those brass-plated clippy things they’re heavy, but seeing as they’re so fat they could double up as cushier backpacking straps on a boat-hauling packframe.

One more annoyance: I was expecting to get the Bravo footpump which the shop I bought it from pictured and confirmed by email. I received the better, hard plastic K-Pump after I went out of my way and bought one. This inconsistency with Incept’s info (including images of models with old colour schemes, velcro decks and talk of ’25 D-rings…’ in current brochures) gets frustrating. You get the feeling Incept aren’t focussed on promoting these IKs, 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.

Sadly, quality of construction is also inconsistent. Most of the boat is heat-welded but closer inspection revealed a lifted seam at the glued-on rudder patch (below 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 by now.
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 any 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 around
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. It’s notably less thick than an old-style Gumotex. Stiffer is harder to glue into tight forms (as proved above) but makes a faster boat on the water. It’s also more awkward to pack, especially when 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 once, theboatpeople spoke sagely about Incepts, though it’s unclear if they’ve actually seen one in the raw (never stopped me!).

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. I must remember never to do that. It’s unlikely that the PVC-U is as durable as 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: a tiny thorn tip picked up while pumping up on Loch Moidart. The second owner’s similarly punctured the side while pushing 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 not be durable enough, but the only other owner of an older red and yellow boat has had no flats at all. It’;s possible earlier boats used different fabrics.

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 – as high as any non-DS 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 up a K40 a bit of a challenge, especially if space is important 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. 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.

The ABS K-Pump is heavier and as bulky as a Bravo footpump, 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. Pop that on a short length of hose and you have a manual – or oral – sucking tube to compact the K40 for transit. If this is all TMI, just say ;-).

nk4-car

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 mountains. Who knows what was up, but I doddered around like a beginner, then parked up on another beach for a walkabout, and on the way back paddled with the deck unrolled which was fun. 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 (left). Remove the four chunky GRP deck-supporting battens, roll the deck back to the right side and hey presto, the legs can breath, you can get in and out gracefully and maybe even carry a light passenger.
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.

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 string and elastic. Not surprisingly, 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.
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: less strokes than you’d imagine. Backing up is also easy with the rudder up and the rudder lift line works fine. A rudder of course came into its own to correct tracking when paddling downwind or at 45° to the wind in either direction, though here is where the mushiness was noticeable. 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 thick 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.

By 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 Summer 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, 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 and it seemed a bit less gust prone out in the open water. After dicking about for a bit, I headed across to Tanera Mor island, about two miles across the bay. We 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. 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. 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. Later, a bigger fishing boat came across my bows leaving a bigger wake which was no bother 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.