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PostPosted: Sun Jan 23, 2011 6:07 pm 
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It's not as elegant as Pirate's solution, but, if the new tyres are a problem to fill, the same effect could be achieved by hanging a bag of lead shot, or something similar, from either side of the cart frame.

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PostPosted: Sun Jan 23, 2011 6:35 pm 
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chrisj wrote:
It's not as elegant as Pirate's solution, but, if the new tyres are a problem to fill, the same effect could be achieved by hanging a bag of lead shot, or something similar, from either side of the cart frame.


I believe Chris that it would still take less weight to counteract the buoyancy of the larger tyres with the water solution as it just displaces and is contained within the tyres, but the weights would work but are likely to be cumbersome at the very least....Pirate

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PostPosted: Tue Jan 25, 2011 10:37 am 
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hi all.
firstly, i'm glad this chap was sorted out. horrible mistake.

ive been sitting on the fence on this post, leaning towards those who accept responsibility for their actions. that said, we all make mistakes and its nice to know that the company we support has feelings too.

for those who didnt know, nothing sticks to polyethylene, of which the hull of Hobie's kayaks are made. so although it would be nice if we could stick things all over our kayaks, we cant. which is probably why the design boffins at Hobie are working on other ways of strengthening the weaknesses of the rotomoulding process.

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tw


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PostPosted: Tue Jan 25, 2011 1:53 pm 
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Its not rocket science, but rather the will and putting the resources in place to do it.

BTW, crazy/superglue sticks to polyethylene.

Keith

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PostPosted: Wed Jan 26, 2011 8:53 am 
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hi chekika, i dont quite understand your first line of your response. can you possibly clarify what youre trying to say.

secondly, have you any proof (thats substantial) that 'crazy/superglue' does stick to polyethylene (pe)? what have you glued to it? how long has it been glued for? what pressures are exerted on the glued joint? have you any technical experience in working with pe and if so, what?
this crazy/superglue, does it have a trade name or is it another chinese export? i'm very interested because i've a fantastic idea but without the means to attach it to any kayak hull, its actually a useless idea. technically speaking, nothing sticks to polyethylene. (BTW)


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PostPosted: Wed Jan 26, 2011 9:58 am 
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super glue or the brand name "Crazy Glue" are both cyanoacrylates. I've got quite a bit of experience with them pertaining to my other hobby of model airplane building/flying. Im not an expert or chemist ... but I didn't think "crazy glue" would work with polyethylene so i looked it up

Quote:
Polyethylene and polypropylene are also materials which cannot be easily glued
with cyanoacrylates (only with a special primer).


from here - http://www.fisnar.com/cm/pdfs/Dynamics_Part_2.pdf

a personal experience note on using Cya's - buy from a hobby shop that does alot of turn over of stock. These glues are best used fresh which is under 6 mo. from production. Major brands oh hobby glues will have a born date on them indicating how fresh the stock is. I can guarantee the stock in the "Crazy Glue" bottle sitting on the rack in the local 5 and 10 shop is quite old ...

Once opened, seal tightly and store in a refrigerator for longest life cycle. The tight seal is to keep moisture/humidity out which is the catalyst for polymerization (drying/curing) of the Cya

Also be aware that quite a few people have developed exposure allergies to Cya's (and epoxy's too) exibiting flu-like symptoms / respitory difficulties that last from several days to weeks. I have friends in the hobby who get sick from just a wiff of the stuff where years ago we'd be building with our hands caked in it. These days I'm alot more cautious. Also, never work with your head directly over / close to what you are working on as the vapors rise and your eyes will burn for several sec's. View from a side angle and avoid breathing in the fumes as well.

A few years ago I finally built a dedicated building board with downdraft ventillation to outside the garage.

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PostPosted: Wed Jan 26, 2011 10:48 am 
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hi allan. i appreciate your input and accept that glueing wont be an option, as advised. ho hum..

tw


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PostPosted: Wed Jan 26, 2011 11:39 am 
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Matt:
I have seen alot of feed back on this post and some good solutions to re-enforcing the scupper holes. My day job is a plastics engineer and mold maker, and I am very familier with rotomolding and insert/overmolding (a leading expert in the field of plastics and insert/overmolding). The solution below uses injection molded sleeve inserts (should be under $1.00 each in production volumes for the sleeves). The solution below can be used on your existing molds with no modification to the molds themselves, and should never leak. You can also expand on this solution to add bulkheads to the boat structure, as well as re-enforce the front AKA cross bar and Mirage drive structures as well as strengthening the bow structure (for the future jib). For development and small quantity purposes (used for product testing), the sleeves can be made from a rapid prototyping process called SLS (selective Laser Sintering) using glass filled nylon ( sleeve prototypes would cost around $50-$75 ea). There are also ways to increase the wall thickness in some of the critical structural areas on your existing molds like the scupper holes (but would require some mold modification).
Hope this helps
Bob
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PostPosted: Wed Jan 26, 2011 1:25 pm 
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My first statement is straight-forward, and I don't care to discuss it more--see fusioneng's suggestions in the preceding post.

Superglue is standard glue for attaching a hatch seal (see Hobie AI/TI front hatch) to the solid hatch cover. Give it a try.

Bob, that structural design is way over my pay grade, but it looks like good info. BTW, your Tandem pictures/info you posted on another thread look very impressive. Lots of worthwhile creative suggestions there.

Keith

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Last edited by Chekika on Wed Jan 26, 2011 2:38 pm, edited 1 time in total.

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PostPosted: Wed Jan 26, 2011 2:20 pm 
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Quote:
Matt:
I have seen alot of feed back on this post and some good solutions to re-enforcing the scupper holes.


Thanks. We have plastics engineers on staff. Yes, we have reviewed these types of ideas and many others.

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PostPosted: Wed Jan 26, 2011 3:34 pm 
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Roadrunner has reported great results using Scotchweld DP 8010 to repair PE.
His tests show that it does stick well.
Slightly off topic but as we have some plastic engineer input I'm hoping to know exactly what the rudder assembly is made of -injection molded glass reinforced nylon? Is there is a glue I could use that would repair the rudder assembly cracks I posted about here?
viewtopic.php?f=69&t=32924&p=133581#p133581


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PostPosted: Wed Jan 26, 2011 4:08 pm 
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trippingwet wrote:
for those who didnt know, nothing sticks to polyethylene, of which the hull of Hobie's kayaks are made.
regards
tw


Hi, we have an experienced plastic welder on another forum here in Australia, he acquired a Hobie Kona with a very similar issue. In researching best ways to repair the scuppers he made mention of a glue that "will" stick to HDPE,
Quote:
one of the very few glues that will successfully stick to HDPE is 3m Scotchweld DP 8010

after much research he also found it was down right expensive with a minimal life span of 6 months stored refrigerated.
Quote:
I did find the glue I wanted when I contacted the supplier, $44.00 for a 35ml tube and you have to buy a box of 12 and 6 weeks from the US.


It was also suggested that Selleys also produce a HDPE adhesive but we were unable to ascertain any further information. Presumably, there are glues that will work with HDPE, I say presumably as I have not personally seen it.


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PostPosted: Wed Jan 26, 2011 7:18 pm 
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I bought some a while back to carry in my emergency spares. It was about $60 delivered. I haven't needed to use it yet. The shelf life is a worry but I figured it was cheap insurance for a remote expedition. It lasts longer unopened.
I got it here. You don't need to get the mixing applicator.
http://www.adept-industrial.com.au/cate ... =1&level=2
They were very helpful and know their product.

PS- Don't confuse it with DP810 which Blackwoods stock. DP8010 is what is needed and Adept were the only stockists in Aus that I could find.


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PostPosted: Wed Jan 26, 2011 8:36 pm 
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They are an Aussie company stringy, thanks I will pass that on as we could not find anyone here.


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PostPosted: Wed Jan 26, 2011 10:44 pm 
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trippingwet wrote:
technically speaking, nothing sticks to polyethylene. (BTW)
trippingwet wrote:
hi allan. i appreciate your input and accept that glueing wont be an option, as advised. ho hum..tw
I'm no rocket scientist, but tripping, I think you're all wet.

As Stringy pointed out, some of us here have been using 3M Scotchweld DP 8010 and DP 8010 NS for a few years now. Here's an application used as a structural reinforcement in a high stress area that quadrupled the life span of the old cam column design:
Image
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Here's a permanently bonded drink holder:
Image

Six months shelf life refrigerated? That's what they recommend, but these projects used a batch stored about a year at room temperature; no detachment whatsoever.

Not a 3M fan or can't get it? Why not try Loctite 3030, another excellent HDPE bonder. Need to seal and reinforce a leaking drivewell stress crack? No problem:
Image
Image

Here's a recent project, a flush mount PE drivewell plug for soloing the new Oasis...
Image

...glued to PE spacers and the original drivewell plug:
Image

This was a fresh batch of product -- made in 2007. I just did this project last week (I do keep it refrigerated though). Even works way past its expiration date -- imagine that!

Strength: Here are a couple of HDPE sample disks that I smeared some (fresh) 3030 on. They were unprepared (no solvent, cleaning, sanding, pressure, etc). Here I tried to separate them with pliers and only succeeded in breaking one of the disks:
Image

The only way they could be separated was with a hammer and chisel:
Image

If you will examine the separated disks, you will see that none of the glue detached from the PE bond on either piece, but ripped within the glue itself:
Image

I hope this has provided you with enough specific information on products and projects to spur you on to actually try one one these excellent products.

trippingwet wrote:
i'm very interested because i've a fantastic idea but without the means to attach it to any kayak hull, its actually a useless idea.
Looking forward to seeing how your fantastic idea turns out! 8)


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