C-Forum

Hi my single sticker peers,

I just encountered another problem with my ongoing re-fitting of saddles to our Sparks. In the boat equipped with a North Water adjustable saddle, where the daisy chains came off already, after tearing these off I found a couple of cracks in the top layer of the Royalite. These open up when pushed from below.. and extend for quite a stretch to half the lenght of the patches.

I suspect that a little "overuse" of glue by the first outfitter (t'was the flexible, clear kind of probably acetone-containing contact cement - at least I got the rest off with Acetone) is the culprit here. Did anyone of you make the same experience with their royalex cracking due to "chemical" and force stress under glued-in PVC?

I wonder if I now just go ahead and glue the PVC back in (with new daisy chains, that is) or maybe first try to repair the cracks
to keep them from worsening..

And how would I do that.

Any experiences would be nice to hear. Keep in mind this is Royalite, so if anyone knows about any diffs between the materials needed to work on this (different inside layer materials? or is it just less thick???) let me know!

Cheers & thanks again guys, you keep us above the water
(literally ;D)

Jan

The previous owner of my Dagger Dimension OC2, which I very recently purchased on the cheap, had fiberglass laid up under the bow and stern outfitting positions, so the saddle, knee pads and straps anchors attached to glass, not the boat. I think it was a really good idea and the boats been around for 20 years, so something is going well there.

I have no such experience with acetone glue ruining the royalex but it sounds more than reasonable.

I agree..... Some interior attachments, particularly those for pedestals and for thigh straps, put a substantial pull against the inner layer of the Royalex/Royalite sandwich. In the case of the pedestal, the attachment chain pulls up, while the pedestal pushes down, and the paddler's leg is pushing down, all in the same zone. Then you run over a rock.....

A two layer concentric Kevlar patch put down on top of the Royalex will spread the push and pull. I prefer to remove the vinyl before using epoxy to glue the Kevlar down. You can also use polyester cloth, but glass might lead to splinters. I use a low angle chisel to remove the vinyl, right at the vinyl-ABS interface. Sanding is too time consuming and imprecise.

I avoid most of this problem by using the center thwart to hold my thighs down, and to hold the pedestal down. That means no thigh strap or pedestal strap connections. But I don't roll open boats, while those who do will want to have knee straps.

Good idea to do a Kevlar layup under the outfitting. Depending if we will want to go boating tomorrow or not (;D).

Omg my neighbour is scre*** his SO so loud I will be deaf tomorrow so no boating. I guess its going to be layup then ;D

Oh, I posted some images of the cracks here:

http://www.ipernity.com/doc/mahyongg/76 ... 1269624760

Cheers & thanks

Jan[/img]

Be careful with that chisel - as I understand it, Royalite is lite because it does not have the inner or outer vinyl layers. You should already be at bare ABS. Sand it maybe, but I don't think a chisel is called for with this.

Here's an idea.

1. Drill the ends of the cracks to stop their progress.
2. Dry boat if there is any water seepage out of the cracks. You might try a hair dryer.
3. Buy a 1/32" sheet of ABS plastic large enough to cover the entire area where the cracks are.
4. Sand lightly the area where this ABS sheet will go and sand the bottom of the ABS sheet.
5. Glue down with G/flex epoxy, following the instructions.
6. Weight with sand bags while the glue dries.

I did this on the interior bottom area of an Ocoee and it's working really well. No need to chisel the vinyl layer (if there even is one with Royalite).

Mahyagongahaha. or whatever your handle was, the damage from the "glue" or solvent does not look that severe. On my Synergy, a leaking can of acetone bubbled up the inner layer of ABS, mixed it with the foam, and temporarily softened the outer layer of ABS. Eventually the bubble-up receded and leveled, and the outside of the hull hardened. I haven't done any compensatory repair yet, although I'll probably put a couple of layers of Kevlar inside.

If you choose an ABS sheet repair, oval the shape of the patch, and feather or taper the edges before you glue it down. The purpose is to avoid any marked transition zones that might cause cracking later on. Straight edged patches, or straight edged ABS panels, can cause that.

Hi,

thanks for the advice guys. I am still pondering wether using Kevlar or ABS sheet, I'd actually prefer the latter being a cleaner, nicer looking result (if I can find one here, that is, during next week.. will be hard enough to get G-Flex shipped out to me fast enough! Dooh..). I will feather and round the corners, great advice.. keep the stress zones spread out, that is.

Btw. I can repeat that advice towards anyone glueing in D-Rings as well.. I once did an optimization of welded PVC backpack strap mounts (the lower ones on waterproof packs) and learned a lot about the pull forces in PVC fabrics in the process. Will try to use that knowledge in my next outfitting, might be interesting to many because it will be home-made and all glued.. but anyways, things to come ;D

Royalite as far as I can see it has a layer of PVC inside and out, just the inside ABS layer is half as thick as the outside while the overall thickness is already less than regular Royalex. Then it haz an outer protective film of some sort (comes with or is the reason for the funky camo of the Sparks - its actually in the laminate to protect the print - which is fine for me because that means it protects my boat ;D).

The inside PVC is so thin, you can wipe it off with Acetone if you want (or if you're trying to get rid of scraper marks, that works as well). In the boat I'm working on, you might even see it in the picture, white ABS is already shining through. Unfortunately its not enough to glue the cracks back together.. so I guess I will use G-Flex, and something else.

About the drilling.. reminds me to say that the cracks are not visible, and I suspect dont even reach the outer ABS layer. They do widen when I push from the outside though so I guess the foam is cracked as well. No wonder given how soft it is..

Do you think I should open the cracks and bevel them before putting in some Gflex before glueing in a sheet or Kevlar, or would just putting whatever sheet above be ok. I see this taking the pull forces in the sandwich then, so could be good. Not that I would just put GFlex in the crax and leave it at that, as per the usual cracked hull repair style advertised with gflex..

;D

cheerio, tomorrow is tandem time again! there's always a good thing coming with a bad thing, eh?

jan

Hi Jan,

My Outrage is full of these cracks! I don't think it necessarily relates to adhesives, just pressure - my boat's cracks are not all near vinyl outfitting, just places where there is lots of stress & occasional collisions. Paul has some too, and has also done some G-flex work recently, so talk to him too if you haven't already.

I did as Milkman outlined: stop-drill the cracks; open them & bevel them wide with a sharp knife (I put a pair of rolled up socks under the boat); fill them; and cover them.

Initially I used the expensive 3m 2-part adhesives to fill the cracks, and then I put in 2 layers of thin ABS sheet as described - concentric, bevelled, rounded, glued with thin layers of the 3M. This is all at the front of my saddle around my knees and has been OK for several years now (if it still cracking under there, at least I can't see it!). I put the ABS around my existing outfitting, so I didn't need to attach any anchors to the ABS sheets.

I also have newer cracks elsewhere, and just quickly repair them without concern, just filling them with Aquaseal (or even Goop) and leaving them as uncovered strips of Aquaseal, which is tough, flexible, see-through, easy to get, and afforadable, so I like it for this. For me, other adhesives or epoxies have proven too brittle for these high-flex areas and have re-cracked (not sure about the ones under the ABS, though I've also cracked the ABS plates themselves). I also went with the ABS sheet instead of fiberglass because I had fiberglass cause problems due to differential flex and eventually coming off - just too much flex right around the knees, thigh anchors and saddle-front.

Every situation is different and requires a bit of creativity - good luck with yours!

Pat.

Pat's experiences suggest that if we could dissect the ABS structural layers of Royalex/Royalite boats, the tension cracks that show up on the inside of the boat would be mirrored by tension cracks hidden on the inside of the outer ABS layer.

Composite boats readily show wear and structural damage. Royalex hides some of the damage, but it is probably worse than one can see without a post mortem.

Is it possible that the hull took a heavy hit in cold weather/water after having acetone leach some of the plasticisers out of it? Seems plausible. Don't know how likely.

Zappaddles

That's been more or less my experience - cold water + impacts.

But I honestly never thought it had much to do with adhesive vapours, my d-rings were hard plastic, not big vinyl anchors, so used less-obnoxious adhesive. I guess over time maybe the Royalex under vinyly-to-vinyl adhesive could weaken, and it certainly can do damage if not used properly.

The assumption I'd made about my boat was that maybe it had been stored in the sunlight too much by the previous owner.

But it might just be the kind of stresses you're putting on your particular outfitting. On the brightside, in my case they've been relatively easy to deal with and haven't affected the utility or longevity of my boat.

How's it going Jan?

Pat.

Hi all,

we now aquired (for 2,75 apiece, which I think is pretty nice) 2 1mmx30cmx50cm sheets of ABS and plan to glue them in with GFlex (the German Importer opens tomorrow, hope they can ship it out here quick!). I will check the cracks, maybe open them up a bit to get adhesive between the parted foam layer.

I just though about the cracks being caused by some sort of chemical reaction because it looks so distorted and the cracks occur right in the zone of most wrinkled surface, but maybe they have also been caused by stress alone. I guess I hit a rock or two with it, with all those little ones in the Lower Seymour and whatnot D8!

Since we will reglue the saddle daisy chains into the boat, we will have to cover the whole area up again with PVC over the ABS. In the end it will stiffen up the whole bottom under the saddle and strap D-Rings to some degree, so hopefully the added stiffness will not effect impact resistance.

Pat, your experience makes me believe that CB will get some more years out of her boat! I am also not easily put off by the need to do a repair every once in a while, in fact I enjoy the challenge as one that comes with boating.. David and Paul can tell you more about how I like to work on boats ;D

Will definitely share the experience and try to document the process & how it comes out. Cleaned it all up quite well already, so now I am looking at a bare PVC surface with some warping and cracks..

The only thing is, today would have been a paddling day if we would just have a boat. Bummer. So we just went past that stupid strainer from last weekend and took some pics.. will put them online somewhere close to the others on http://ipernity.com/doc/mahyongg later ;D

I hear the Beaver seasons first paddle moved along today, widgeon creek if I am right?

We are btw. scheming towards hopping over to show you our great repair skills sometime in september. Maybe it works with Tamihi this year.. ;D

"C" U,

jan

Not so much the vapors. If the acetone, or any similar solvent, is allowed to dwell on any plastic it has the unpleasant habit of (to some degree) disolving it, or at least rearranging it's chemical make-up, out some of the components that make it desirable for boat building; think acetone disolved ABS patches that are too quickly applied between coats. I'm sure there is a chemical engineer or a chemist out therre who could shed more light on the subject.
Zappaddles

Yeah, with the warping & wrinkles, sounds like it was chenical damage, whereas mine seems to just be straight-up cracks.

Good luck Jan, putting vinyl down on top of the ABS sheet and then the outfitting sounds like a whole of glueing - I hope it all holds together!

I know you already have the ABS, but I've also heard some swear by just putting down an inner layer of vinyl.

Pat.

p.s. Widgeon was the other week, club's first ww trip was the lower Chilliwack today. I hope Ellen did OK in her new Solito! I think there were a few other new ww boaters too.