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 eight IKs, three packrafts and a couple of slackrafts and have only had one unexplained tiny pinprick puncture in the Incept. It’s hard to think of anything puncturing my full Nitrilon Gumotex IKs or the Grabner. I 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, slather on adhesive to both surfaces, wait then slap on the patch and press down hard to achieve a long-lasting bond.
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 off 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 a patch of wear, as shown above (not an actual puncture).
However, 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 then press together and roll very hard with what’s called a seam roller (left; like this one for £2). I’ve since found a better tool – a Sealey TST15 patch stitch roller; right – used to roll down inner-tube and tyre-repair patches to remove trapped air and ensure good adhesion. Applies much greater pressure and only a fiver on ebay.
Allowing it 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. And after press-rolling it doesn’t hurt to leave a repair under a weighted stack, overnight, as shown right.
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 a runnier version of Aquaseal to get into cracks, and 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.
Better to use the much stronger two-part adhesives out there suited to actually making rubber or PVC 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 up to a quarter of the price of similarly effective Aquaseal. Ribstore and Ribright (right) in the UK sell similar stuff – just make sure you buy for Hypalon or PVC. I used it to glue D-rings onto my Grabner (more here), floor patches to my Alpacka, latex socks to my dry trousers and patches to my Nitrilon Seawave, It sticks like shit to a s***el. Good video below: learn from the experts.
I have to say the one-part rubber glue supplied with my Gumotex IKs and Grabner are a last resort – looks like something from a bicycle repair kit. I’d sooner use two-part but have a feeling that when it comes to gluing, rubber-based fabrics are less fussy than stiffer and slipperier PVC/PU, but much depends on what you’re gluing – a simple patch repair or a D-ring fitting that may be under strain.
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 smaller 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.
The other glue I used on my PU/PVC Incept IK (and Slackrafts) is Bostik 1782, being unable to buy the two-part Bostik that NZ-based Incept recommended in the UK, and not least because the 1782 was going 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 PVC a bit.
Aire-style bladder boat repairs are actually easy on the urethane cells. 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 too 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 so easily or securely repaired with tape. In fact it would be difficult to bond anything well to the slippery nylon fabric compared to smooth urethane plastic, but perhaps once inflated the seal would have been fine.
Once you’ve done your sand papering (an essential part of a repair kit – see video – or use a rough rock) 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 perfume, nail polish remover (acetone), lighter fluid, white gas or petrol of course, but not oilier diesel, aviation fuel or Nivea. Bleaching agents aren’t the same thing, but might work too. In the end just use water to remove the dusty 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? above right) or nail polish remover are easy to find at a chemist or tobacconist and handy to pack. Back at home I’ve found MEK (Methyl Ethyl Ketone; white bottle, above) is inexpensive at £10 a litre and effective. Acetone is even cheaper and perhaps less extreme – all we’re really talking about is cleaning off and 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 MEKed. Even on rubber-based coatings use MEK or 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 (one ‘T’ in ‘TNT’) for hypalon and similar which on ebay is a bit cheaper than MEK. Afaik this stuff is restricted and won’t post in the USA – in the UK they flog it all on ebay.
Big tears and bear bites
If you have a huge gash, as in the folding Klepper’s hull on the left, 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 on the left caught a cut-down metal fence stake buried in the 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.