Tag Archives: Helaplast

Sigma TXL • bow skeg and thigh straps

Sigma TXL main page
Glues and Repairs

Years ago I remember when the value of fitting packraft rear skegs was debated. Then, the now common longer sterns (introduced by Alpacka) positioned the paddler more centrally and greatly reduced excessive bow yawing.
On a packraft you’d think a skeg under the bow would eliminate the yawing endemic to short, wide rafts but turning agility would be lost. In fact, I wonder whether a packraft might yaw nearly as much at the back but you never notice. Like one of those Turkish dervishes, you’re actually pivoting from the middle of the paddle shaft, or perhaps a bit behind, at the centre of mass.

Rear skegs certainly improve tracking on IKs; you can manage without, but with a skeg you can paddle harder without constant micro-correctioning. On rivers I’ve found solo packrafts paddle fine without a rear skeg; or they’re too short to demonstrate noticeable improvements. There’s a bit of nodding as you move off which soon settles down with some momentum. Even my symmetrical Rebel 2K (left; stern identical to bow, not extended) paddled fine down the Wye without a skeg. But when getting pushed around by the swell or on sea lochs (especially when sailing) fitting a skeg was worthwhile.
Either way, rear skegs are a thing now with packrafts even if you don’t have to fit them every time. Certainly on my longer TXL I like to think the stock rear skeg aids coastal paddles; though we found a brief stint with no skeg was only slightly noticeable, paddling into the wind in a sheltered loch (no swell). Anyway, I’ve been curious to see what effect a frontal skeg has, so on buying my TXL I ordered a spare skeg and patch which Anfibio also sell separately for €21 + €6.

Goop no good; Aquasure OK; Helaplast better

Gluing on a skeg patch
As stick-ons go, this is not a mission critical job but you want to line it up dead straight which I now see is better done with the boat inflated. I just used the rear seam, hoping it was along the middle line. Anfibio recommend Helaplast which they can’t post outside of Germany but which you can buy on ebay.uk (from Germany…) for €7 for 50ml.
There must be something similar in the UK, but the problem is identifying it against something that provenly works. I had some Goop contact adhesive, but whatever the ‘Automotive’ variant is, it did not stick at all. So I decided to try some Aquasure+FD, leaving it to cure for half an hour before sending in the roller. That seems to have worked.

Using stock TXL mounts sort of works

Thigh straps
Part of me likes to think I’ll be using my nippy TXL the way I use my IK: fair weather open-water transits rarely more than a mile from shore. As this might require sustained periods of paddling I figured some thigh straps would help, as they do in my IK. It’s not so much for hardcore bracing or even rolling, the way they’re used in white water, but just to lock-out the legs so the core is more responsive and you can get good drive, as with knees pressed up under the deck of a hardshell sea kayak.

Anfibio sent me their latest 5-point thigh straps which I tried and liked on the Revo (left). But to make full use of them would require gluing on up to 8 extra patches (if not ideally the ladder patch; left).

I decided my old Anfibio 3P straps which I’ve used for years in my IK would be OK for my low-tension, flatwater use, and require adding just one pair of loop straps. I could have got away with the unused flat patch by the seat, but the direction on tension was off centre and would eventually wear, stretch and maybe break. These small patches are not really designed for such loads and now my Helaplast has arrived I decided to try it. An old post on the Anfibio blog explains how to use Helaplast:

  • mark off area on hull
  • mix hardener 20:1
  • clean surfaces with solvent
  • apply a thin layer to both surfaces and wait 30 minutes
  • apply another thin layer and wait another 10 minutes
  • Position patch; it won’t adhere properly
  • Heat with hair dryer to reactivate glue and press down hard (it’s better if the boat is deflated to do this on a hard surface).

The heat reactivation trick was not one I’ve heard of before with glues (except to loosen stuff), but you could see it worked. Where the positioned patch was lamely stuck to the boat, a bit of heat saw it bond down well with some some added rolling. You can tell when something looks well glued and this feels like it, though I’m sure glad I didn’t have to do that another six times.

Update
Having paddled about with the straps a bit, they work OK, but the front mounts need to be lower to hook well over the knees without using the cross-link strap to pull each strap inward (not what they were intended for). I did this a few days later.

Thigh strap attachment points are better off set low at the front.

IKs & Packrafts: glue & repairs

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

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 packrafts use two-inch wide Tyvec 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 or use ultra tacky Gorilla Patch & Go tape for deep floor scratches and cuts. It will remain impermeable even once immersed.

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.

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.

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.