Tag Archives: Nitrilon repairs

Repairing a Gumotex Seawave

lm-pumperThe other day, while lashing the Gumotex drybag backpack to a chopped-down trolley I foolishly wore two holes in my Seawave ;-((
Pumping away like a donkey on Limehouse jetty (above), I assumed the non-standard PRV was playing up; probably a grain of Achnahaird sand stuck on the seal. I flipped the cap off, tried to clean it out by springing the valve from behind but no luck. So I gave up and was ready to dismantle or replace it later.
It was only when sw-holesfrustratedly rolling up the boat I noticed two small ragged holes in the hull and realised what had happened. With half a paddle shoved into the cinched-up bag to make a handle, and it all lashed in a to the trolley, I thought I was being rather clever and minimalistic. But strapped to the trolley, the pack soon sagged under its weight and rubbed on the sharp edge of the hard plastic wheels which wore through the pack and then the boat’s hull.
The cut-down trolley had worked fine with my UDB drybag in New Zealand (left), but that was partly because you can fully inflate a UDB via its unique one-way oral valve, transforming it  from saggy sack to firm sausage.
Ironically, just two days before this happened, I’d snagged a BNWT Orlieb RS140 (right) cheap on ebay. I’d been eyeing up this non-rigid wheeler duffle as a versatile Seawave transporter plus reliable on-water drybag/buoyancy aid (review shortly).
And what’s more, inventing the wheel was all very well but to be honest, for short 10-minute spells of urban pavement walking between trains and buses (as opposed to traversing Scottish glens), the 17-kilo Seawave is not so hard to carry as a backpack. Lesson quickly learned.


With enough practice with D-rings, let along bike punctures over the years, I was confident I could do a bomb-proof repair on the Seawave. In a way, I was even a little chuffed that my 5-year old kayak was earning its first battle scars. Plus, in my experience rubber-based IKs like Gumotex, NRS and Grabner glue more reliably than PVC boats. Shiny packraft TPU is even easier: you can just tape it, but packrafts are low-psi boats not normally inflated with mechanical pumps. My adapted Seawave side tubes run 4 or 5 psi.

ami-polyThings you will need

  • Patch
  • The right two-part glue (right)
  • Solvent and rag
  • Sandpaper or abrasive foam sanding block
  • Masking tape
  • Small brush
  • Tyre repair roller (right)
  • Space to do a good job

 

STEP 1 • Match up a patch from your collection, ideally identical fabric. For a small hole extend the patch at least an inch.

STEP 2 • Clean the punctured area and patch surface with solvent and wipe dry. This time all I had was brake cleaner spray, but ordered some toluene for next time.

STEP 3 • Sand down the two surfaces and then clean and wipe again with solvent. Avoid touching these cleaned surfaces with your fingers.

Some colour coming off is a good sign you’ve removed any sheen or patina.

STEP 4 • Position the unglued patch and mask the perimeter with tape to avoid excess residue and to help with positioning. If the patch is not perfectly symmetrical (like above) mark it – but make it bold – I still got it wrong!

STEP 5 • Mix up some two-part Hypalon (Nitrilon; EDPM) glue. It’s rare than one-part glue works as well, but Aquaseal has worked for me, gluing a skeg-patch to a Grabner.

I found some mini brushlettes in my repair kit box – they must have come free with some glue.

STEP 6 • Brush on the glue thinly to the two surfaces. With Polymarine you then to wait 30 mins for it to cure/dry, then apply another coat and wait till touch dry (5-10 mins). Here’s their full guide: http://www.polymarine.com/advice/hypalon-adhesive-how-to-repair-inflatable-boat-tubes

You can see I made typical errors: mixed up too much glue (but better too much than not enough)…

… and applied too much glue on the patch…

… but a just-right thin later on the hull.

STEP 7 • With the deflated boat repair positioned on a firm surface like a hard floor or better still, draped over a wooden stool, carefully lay the glued patch over the damaged area…

… then – STEP 8 • peel off the masking tape and ROLL DOWN HARD moving from one edge to the other and again at 90° and again diagonally with your Baltic pine-handled roller, making sure the edges have stuck down. It won’t hurt to roll again in 20 minutes and again after an hour to make sure the two parts have well and truly bonded till death do them part. And actually, only about 25% of the glue was wasted.

In 12 hours the repair is cured and ought to last the life of the boat. Never do that trolley thing again!

 

Inflatable kayaks: glue and repairs

Updated summer 2020

See also: Repairing a Gumotex Seawave

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 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.

rep-hull

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.

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 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. 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.

It’s worth noting that McNetts Aquaseal / Aquasure (same thing sold in different territories) calls itself a waterproofing sealant not an adhesive. 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.

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 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 to send you 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

ami-poly

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.

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 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

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

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.

IMG_5304_1