Has anybody fixed a plastic canoe?
Has anybody fixed a plastic canoe?
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gib6933

Original Poster:

5,278 posts

261 months

Monday 19th April 2010
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I have been asked if I can fix a canoe for a friend, it maybe a GRP one if so I have no problems.

If its a plastic one I may have a problem sticking anything to it.

Has anyone fixed one before? Can I plastic weld it?

Smart roadster

769 posts

256 months

Monday 19th April 2010
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You can get hot air welders that will repair PE canoes. It is an industrial hair dryer. It isn't deperatly difficult to do but you have to be careful not to over heat the base material as you could end up with a big fking hole or just "burn" the plastic so you get age hardening around the repair.
You can probably hire the welder from a good tool hire place. If you get filler from them i'd give the surface a good rubbing down as the surface gets a bit grubby and can cause problems in the weld.
I haven't done any PE welding for years so the state of the art may well ahve moved on.
Oh and do it somewhere well ventilated that stuff stinks.

Rollin

6,336 posts

275 months

Monday 19th April 2010
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Canoe story

bloke on internet said:
A friend of mine once built a canoe. He spent a long time on it and it was a work of art.

Almost the final phase was to fill both ends with polyureathane expanding foam.

He duly ordered the bits from Mr Glasplies (an excellent purveyor of all things fibreglass) and it arrived in two packs covered with appropriately dire warnings about expansion ratios and some very good notes on how to use it.

Unfortunately he had a degree, worse still two of them. One was in Chemistry, so the instructions got thrown away and the other in something mathematical because in a few minutes he was merrily calculating the volume of his craft to many decimal places and the guidelines got binned as well.

He propped the canoe up on one end, got a huge tin, carefully measured the calculated amounts of glop, mixed them and quickly poured the mixture in the end of the canoe (The two pack expands very rapidly).

I arrived as he was completing this and I looked in to see the end chamber over half full of something Cawdors Witches would have been proud of. Two thing occurred to me, one was the label which said in big letters "Caution - expansion ratio 50:1" (or something similar) and the other that the now empty tins said "approximately enough for 20 small craft."

Any comment was drowned out by a sea of yellow brown foam suddenly pouring out of the middle of the canoe and the end of the canoe bursting open. My friend screamed and leapt at his pride and joy which was knocked to the ground as he started trying to bale handfuls of this stuff out with his hands.

Knocking the craft over allowed the still liquid and not yet fully expanded foam to flow to the other end of the canoe where it expanded and shattered that end as well.

A few seconds later and we had a canoe with two exploded ends, a mountain of solid foam about 4ft high growing out of the middle, and a chemist firmly embedded up to his armpits in it.

At this stage he discovered the reaction was exothermic and his hands and arms were getting very hot indeed. Running about in small circles in a confined space while glued to the remains of a fairly large canoe proved ineffective so he resorted to screaming a bit instead.

Fortunately a Kukri was to hand so I attacked the foam around his hands with some enthusiasm. The process was hindered by the noise he was making and the fact he was trying to escape while still attached to the canoe.

Eventually I managed to hack out a lump of foam still including most of his arms and hands. Unfortunately my tears of laughter were not helping as they accelerated the foam setting.

Seeking medical help was obviously out of the question, the embarrassment of having to explain his occupation (Chief Research Chemist at a major petrochemical organisation) would simply never have been lived down. Several hours and much acrimony later we had removed sufficient foam (and much hair) to allow him to move again.

However he still looked something like a failed audition for Quasimodo with red burns on his arms and expanded blobs of foam sticking everywhere. My comment that the scalding simple made the hairs the foam was sticking to come out easier was not met with the enthusiasm I felt it deserved.

I forgot to add that in retrospect rather unwisely he had set out to do this deed in the hallway of his house (the only place he later explained with sufficient headroom for the canoe - achieved by poking it up the stairwell.

Having extricated him we now were faced with the problem of a canoe construction kit embedded in a still gurgling block of foam which was now irrevocably bonded to the hall and stairs carpet as well as several banister rails and quite a lot of wallpaper.

At this point his wife and her mother came back from shopping......

Oh yes - and he had been wearing the pullover Mum in law had knitted him for his birthday the week before.

davemac250

4,499 posts

235 months

Monday 19th April 2010
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Fixed a few GRP ones, as you say no problem.

Historically if a plastic one was holed it went to the skip.

I am not sure even the best modern plastic weld would hold. OK if you are somewhere safe/slow and it pops a leak, not something I'd fancy in surf/white water.

I suppose if he does want it fixed a work around 'could' be to plastic weld the damage then get a very hi-tac sealant and put a second panel across the back of the repair to spread the loadings a little. Some of the stuff I have used recently is easily strong enough to take the pressure and now are very very adhesive. rough up the inside and clean off with a alcohol solvent should do the trick.

Then get a mate to test it. Preferably without letting on!

gib6933

Original Poster:

5,278 posts

261 months

Monday 19th April 2010
quotequote all
davemac250 said:
Fixed a few GRP ones, as you say no problem.

Historically if a plastic one was holed it went to the skip.

I am not sure even the best modern plastic weld would hold. OK if you are somewhere safe/slow and it pops a leak, not something I'd fancy in surf/white water.

I suppose if he does want it fixed a work around 'could' be to plastic weld the damage then get a very hi-tac sealant and put a second panel across the back of the repair to spread the loadings a little. Some of the stuff I have used recently is easily strong enough to take the pressure and now are very very adhesive. rough up the inside and clean off with a alcohol solvent should do the trick.

Then get a mate to test it. Preferably without letting on!
Its not going to be used for anything extreme. I should ask her if she can swim though smile

I have just the right test dummy friend for testing it out biggrin

I shall post photos of the results.





markmullen

15,877 posts

264 months

Monday 19th April 2010
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Shouldn't this be in the TVR section?

getmecoat

davemac250

4,499 posts

235 months

Monday 19th April 2010
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markmullen said:
Shouldn't this be in the TVR section?

getmecoat
hahahahahahahhahahahahaha NO.

madbadger

11,752 posts

274 months

Monday 19th April 2010
quotequote all
Gaffa tape.