flexible expanding foam

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rogerthebodger

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Any one used any flexible expanding foam to fill deflected fenders or make fenders of floats by pouring mixed components into a damaged fender of mold.

Thinking of the thread on DIY dan buoys this could also be an option for the floats.

could also be used for fixing a leaking inflatable boat or pontoon floats.

Would not disintegrate like rigid /builders foam.
 
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This is an interesting thing I have also considered, as I have a few new punctured fenders after recent gales.

I think that the expanding foam though by its nature mixes and cures to a solid form? I don't know of a flexible type but if you find one I would be glad of a link.


Rogershaw said:
Any one used any flexible expanding foam to fill deflected fenders or make fenders of floats by pouring mixed components into a damaged fender of mold.

Thinking of the thread on DIY dan buoys this could also be an option for the floats.

could also be used for fixing a leaking inflatable boat or pontoon floats.

Would not disintegrate like rigid /builders foam.
Click to expand...
 
All the answers I have had on expanding foam indicate that it sets with a waterproof skin, which forms where exposed to air, and if you dig into that it will absorb water. If you inject it into a container then no waterproof skin.
 
Any one know how foam rubber sheet is made that we all use for cushions in our boats and at home.

I do have a local supplier of foam bed mattresses, may be I should speak to then.

Its really a rubber version of the rigid polyurethane foam you get in a can. Rigid would of cause be no good.


https://www.youtube.com/watch?v=u9Sj1KmmzQI

Seems its quite easy, just need to get the components.
 
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October 10th

I want to make a flushing-water tub for my outboard.

I've got a couple of those insubstantial plastic trunks, tall enough to keep the busy end of the engine leg, well below water.

I want to put one trunk inside the other, and spray some sort of structural packing between them so the considerable weight of water (probably 60kg) is evenly spread, and so that if the inner tub ruptures, I don't have a flood in the garage.

Is expanding foam the answer? I've never used the stuff. Does it dry to a substantial load-resisting structure, or does it squash easily?
 
You don't want to test an ob in the garage. Your lungs will object.

Seen trugs used. Never seen the need to re-enforce

Expanding foam is the son of the devil. It get everywhere. Sticks to everything and is impossible to remove. Kiss.
 
Thanks guys. If I wasn't aware of the asphyxiating fog that is sure to be emitted from the flushing procedure, I would already have tried it out. As it is, I'm obliged to wait for a day when the neighbours are out, then I can put just enough fuel/oil mix in the tank for five minutes' running, and hope that it'll dry up and stop sooner than somebody calls the fire brigade. My space outside is very limited.

Also, I'm not keen to advertise the fact that I keep an outboard in the garage...there have been attempts at nocturnal entry, previously.

But I constructed a fabulous heavy-duty timber outboard bracket before I realised I could just hook the outboard on a dustbin. And having made room under the bracket for a thing like an aquarium, I'm keen now to use the plastic trunk, it's just the right size.

So I want to put one trunk inside the other, and maybe pack the outer one with something that'll reinforce the flimsy plastic.
 
Thanks, but I didn't spend several long dusty July days in the searing Hampshire heat, building this magnificent glowing outboard stand, measuring and sawing, sanding and varnishing, just to be told I could have used a wheelie-bin. :hopeless:

48448305357_753f1d24b2_c.jpg
 
Back in 2006 we went liveaboard for a couple of years. We bought a RORC spec danbouy with a yellow plastic float. The float didn't seem to like the sunlight and started degrading after a year or so. I eventually got round to taking the float off and replaced with with a small fender which I slit along the seam at top and bottom, stuffed the fibreglass pole of the danbouy through it, filled with expanding foam from a Greek DIY shop, waited for it to dry.

It looked quite scruffy (it was a very old and well-used fender). I then stuck it in the oggin for a couple of hours. It floated just fine and didn't seem to absorb any water. It is still in use on the boat now - 8 years later and it still seems to float OK.
 
Daydream believer said:
Considering how cheap a new fender is, do you not think that the exercise is a waste of time? The foam will probably cost 60% of the price of a new fender.
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Jaja, but Greta will give you a right bollocking for dumping more plastic that you might be able to fix and re-use.
 
It's been nearly 13 years since I last posted this (presumably apocryphal) tale, and now just seems like the right time again.


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 polyurethane 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 ration 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 simply 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.
 
stingo said:
Jaja, but Greta will give you a right bollocking for dumping more plastic that you might be able to fix and re-use.
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& mixing the chemicals to make the foam is OK is it?
Where will you put the resulting failure? Lob it in a ditch on the way home? I know, slip it over the side into the sea!!!
But you can give me the split fender to put over the tow hitch on my trailer bar to keep it out of the mud.:encouragement:
 
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Daydream believer said:
& mixing the chemicals to make the foam is OK is it?
Where will you put the resulting failure? Lob it in a ditch on the way home? I know, slip it over the side into the sea!!!
But you can give me the split fender to put over the tow hitch on my trailer bar to keep it out of the mud.:encouragement:
Click to expand...

I'm with Stingo , Repair, Reuse, Repurpose. Recycle.

If I fider a fender floating around I save it from is disintegration and pollution of the oceans.

As Stingo will confirm ther is already too much pollution in Durban and Africa.

My farther was Scottish so I inherited his tight fisted nature.
 
Rogershaw said:
I'm with Stingo , Repair, Reuse, Repurpose. Recycle.

If I fider a fender floating around I save it from is disintegration and pollution of the oceans.

As Stingo will confirm ther is already too much pollution in Durban and Africa.

My farther was Scottish so I inherited his tight fisted nature.
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So you would fill it with harmful chemicals which (whether you like it or not) WILL end up being discarded in landfill one day
That was the point of my post. Not one of removing rubbish from our oceans- a move with which, I heartily agree
 
Remember that a fender is intended to squish when compressed, hence the low psi. Filing it with stuff will prevent it from doing this. You don't want hard fenders.
 
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