Expanding foam sandwich between plastic wrap skin on frame

Discussion in 'Boat Design' started by Quidnic, Mar 15, 2021.

  1. Quidnic
    Joined: Apr 2020
    Posts: 59
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    Location: Wales

    Quidnic Junior Member

    Standard Temporary Fencing is an extremely versatile piece of equipment, ideal for construction sites and outdoor events.

    Manufactured from pre-galvanised steel, these panels come at the height of 2045mm and length of 3450mm. The mesh infill of the panel are also galvanised steel here are some Key Features

    • Made from high quality steel
    • Galvanised to BS EN 10244-2 standard
    • Joints welded using SmartWeld 100 technology
    • Reusable
    • Easy to transport

    Each panel weighs about 15kg and the best part is you can often get them for free. They are designed for temporary fencing for events or projects that once it’s over they are discarded.

    These panels will form the framework for our tiny house boat project. Four can be fixed together with cable ties to make a tunnel of about 3.5M in length and about 2M high. These dimensions can be flexible depending on how you fix the four of them together.

    Once you have them cable tied together, you can get inside and start plastic wrapping the inside which is not as easy as the outside. You can use a paint roller to stick the first layer on the inside and then keep layering it over at least three layers but a few more would be stronger.

    Come right around the inside ends starting at the top and come down halfway one side leaving a gap at the bottom of one end so you can get out. Once you crawl out seal up that gap so it’s completely sealed on the inside. Then start plastic wrap the outside which is so much easier. You should have a gap of about 40mm between the two layers of plastic wrap.

    Once you are ready for the expanding foam make sure the hole you make to insert the foam can be sealed with strong duct tape once you have emptied the contents inside.

    Expanding foam will keep expanding far more than you expected and will always take the path of least resistance. As long as your two layers of plastic wrap keep their integrity it should fill the majority of the cavity. Once you can see it has stopped expanding you will see areas that need more foam shot in. Again make as small a hole as possible in the outside layer and shoot in the required amount then seal up the hole with strong duct tape.

    Leave the finished structure a couple of days to settle and cure. It may expand or contract a little here and there until it settles.

    Next job will be to cut the entrance hatch and windows. Use the lightest double wall plastic or Perspex translucent material you can get. Something like 10mm-clear-twinwall-polycarbonate-roof-sheet.

    A bow and stern section can either be solid foam which would help it to be unsinkable or hollow for extra storage.

    A frame can be made out of wire then plastic wrap again and filled with expanding foam once again.

    The foredeck and rear deck need to be very strong to cope with any knocks and bumps. To run a wire round the full length of the boat inside the foam will add much needed strength.

    The design of this water rat gypsy boat was a big inspiration in my design project but this modern boat will have an even better strength to weight ratio. Latest technology building materials and technologies can produce far superior strength to weight ratio. The entire vessel unladen will be less than 70kg meaning it could be towed by a high powered electric scooter.

    The wheels and axle can be removed and attached as needed and taken with you so that if you go somewhere that you would like to go ashore you can attach the wheels and take out your electric scooter and off you go.
     

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  2. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    I’d suggest foaming the panels in before erecting them, lay them on the ground over a sheet of visquene, or a thin finished panel of glass, Formica or whatever, then pour the foam in, cure and level, then apply finish.
    Cheap insulation foam with thin plywood glued on both sides will probably get you there faster and cheaper.
     
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  3. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    thanks yes that makes sense

    but getting the joints sealed may be tricky

    if you make the entire structure in place first with two skins one inside one outside with about 40mm gap then the expanding foam sound meet up and seal all joints on one go?

    getting the bow section shape as simple as possible is my next undecided decision

    maybe a nice shaped bow and for deck like the sea rat above or something like the Star Trek shuttle
     

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  4. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    A shantyboat is a small crude houseboat (also called a flatboat, broadhorn, barge, scow, or ark). There is a long forgotten history of people living in homemade shantyboats, a reasonable and cost-free solution for displaced people in rural areas and workers in urban areas.

    Reasonable Set of Requirements

    Nothing focuses the mind of a design engineer like a list of requirements. Let us then list out the requirements for a tiny house boat that would work best for our stated purposes. It would certainly be splendid if a credentialed naval architect or two rose to the challenge of carrying out the design work. But even if all selfrespecting naval architects turn up their noses at something so unmarketable and unfashionable, this should not spell disaster: sailboat design is a rewarding area for a creative amateur as well as a professional.


    The tiny house boat must provide accommodation, storage, and transportation for a small family.

    She must be fully amphibious with removable wheels which you can take with you and fit to pull out of the water at the drop of a hat.

    She must be strong and lightweight. Steel framework skeleton for strength but mainly lightweight insulated foam making up most of the hull.

    She must be so lightweight that she could be towed by bicycle or an electric scooter which will always travel with her at all times. On the water she must be able to be towed or sculled short distances with ease.

    She must have standing headroom in one solid structure with no raised roof as with many camper vans and land yachts, in fact no moving parts at all apart from the entrance door.

    She must be quick, cheap and easy to build. So easy and so cheap that even a child could build her with pocket money.

    She must be seaworthy enough to cross short seagoing passages for example the English Channel over to to the French canals, or the Gibraltar straight in fair conditions.

    She will be most happy on canals or river type waterways. Being able to be pulled ashore and be happy on any river bank place where land meets water.

    With generous fresh water tanks and plentiful storage space. She should have shallow draft, to float over flooded lands and shoals, into estuaries, and up and down rivers and canals, and a flat bottom, to settle upright.

    The mast should be stepped in a tabernacle and rigged for easy lowering to pass under bridges and other obstructions. She must be designed to be beached and rolled ashore on her own wheels which always travel with her. She must be very very cheap to build, to maintain, and to operate. She must not require the use of advanced metallurgy or synthetics.

    She must be both wellinsulated and wellventilated, to protect her crew from the weather in any climate and season, both hot and cold.

    Since we expect there to be few rescue ships and helicopters available, our boat must be able to serve as its own lifeboat, containing enough flotation along the sides and the deck, to be unsinkable and selfrighting even when holed and swamped.

    She should look sufficiently unmarketable to avoid giving authorities or local pirates the impression that they could raise some money by seizing her.

    She should be painted dull inattention grabbing colours like dark grey or subtle urban camouflage.

    She should not draw attention on a canal or river or on land anywhere. She should be unobtrusive parked in an industrial estate or round the back of a car park. Stealth camping in the woods or by the side of a road. She could have a tarpaulin or canvass draped over her at anytime to disguise what is underneath even more.

    If someone sees this unusual box thing they won’t bat an eyelid, it could be anything and it’s totally forgettable. Unlike stealth camper vans which try to fit in but it’s very difficult not to show someone is living in there.

    She may look like some kind of dumpster or storage tank to the untrained eye, and most people will pass it unnoticed. This is what you want to aim for with stealth living where ever you end up staying.

    On a trailer towed behind a vehicle she could be parked anywhere and again a canvas strung over her so she can be parked outside any road or put on someone’s driveway or garden.

    The Simplest Solution that Works
    Since almost all contemporary sailboats are designed for either sport or luxury, we can start with a blank slate, and dispense with most of the preconceived notions of what a sailboat must be like. However, there is an established style of boat that is so close to what we want that there seems to be no reason not to start with it. It is called the square boat, or the Bolger Box, after Phil Bolger, a naval architect from Gloucester, Massachusetts, who is a renowned designer of square boats and other unusual craft.

    That such simple shapes can be so effective seemed paradoxical even to Bolger himself, who once wrote (of a boat of his, a perfectly serviceable dinghy called "The Brick," which really is just a box): "It's disconcerting that these box boats do everything better than elaborately modeled boats of the same overall dimensions..."

    Since a square boat is basically just that a square boat, four flat pieces fixed together around and fastened to a transom and pointy bow, building one does not require molds and is wellsuited to backyard or some wasteland construction.


    Lateral Resistance
    Any boat that carries sail must provide for sufficient lateral resistance to keep the boat from developing sideways motion (known as leeway) when it is moving in any direction other than directly downwind. The device usually employed to counter this effect is a keel. A either fixed or somehow movable.

    There is the new but reasonably welltested concept called "chine runners," pioneered by a dedicated hobbyist by the name of Matt Leyden, who has used it on some tiny but quite shockingly capable and seaworthy cruising sharpies. They were used on 32 and 40 foot sharpies designed by Chris Morejohn. Chine runners are only applicable to square boats with vertical sides, and are formed by extending the edges of the flat bottom sideways by a few inches past the vertical sides, allowing the sides to act like keels.
    Early experiments used chine runners to supplement a centerboard; however, it was soon discovered that small boats can sail quite passably to windward with the centerboard retracted. Chine runners are structurally very simple, their cost is low, and they suffer from none of the detractions of fixed keels, centerboards, or leeboards. They are less effective for larger boats, because in order for them to be effective the boat has to heel over quite far, presenting a large vertical surface to the water, and it is easier to make a small boat heel over than a large one, especially in light winds.

    These simple chine runners are ideal to have the wheels fix into when in amphibious mode, as with many design features more than one use where possible.

    This design will initially be met with widespread incomprehension and outright dismissal. Once its many advantages become apparent, it will come to be ridiculed. This may seem strange but it is in fact quite typical. At some point the acceptance phase will see the former die hard critics claiming they always knew it would work after all.

    One Tiny House Boat, Many Uses.

    By far the simplest thing to do with a square boat once it is finished is to move in and live aboard without ever launching it. Its vertical sides and flat bottom make its interior more like that of a trailer home than a typical cruising sailboat. A land yacht that may never touch the water, or hardly ever. This may be a sensible thing to do in an area prone to floods: the boat can be tethered between two posts, floating up and settling as needed. When the land is dry, one bicycles to get around; when flooded, one rows your home around. This approach avoids real estate taxes, but may still require one to own or lease land. Or just guerrilla gardening some waste land and move only if absolutely unavoidable.

    The second simplest thing is to have your new waterproof home launched and towed out to a mooring, which, since the boat only draws a couple of feet, does not have to be in deep water, and can even dry out at low tide.

    Sails need not cost a lot for making short trips in decent weather, a Junk sail can be rigged using lumberyard supplies and construction tarp. For purely aesthetic reasons, white tarp works better socially than the more common blue tarp. If the boat only needs to move a short distance, at a time of your choosing, in order to comply with local regulations for how long you may remain anchored in any one place, this is all you would need.

    The mast could be lightweight PVC pipe which could double as an oar for sculling which is like rowing with one oar.

    This will not be a sea going vessel at all, ocean passages require quite a lot more equipment and preparation. There are, however, no technical problems with a square boat taking to the open ocean, provided she is wellbuilt, equipped, and sailed with sufficient attention and skill. It has been done many times by many people, in square boats big and small.

    Living Aboard
    A small cottage in the woods can be fitted out in as a selfsufficient rustic cabin, with a quaint entrance a wood stove, and firewood stacked neatly under the eaves. In typical shantyboatstyle built using recycled materials for almost nothing.

    This cottage on wheels could even be buried with a light sprinkling of topsoil over her, just enough for weeds to grow. This would make a great survival bunker. Or just half buried with branches and wild debris over the top. Or indeed hidden in undergrowth with branches and bushes placed all around her.

    The shantyboat may feature a stove that can burn charcoal, wood, or any combustible waste. The heads (the nautical term for latrine) can consist of a bucket with a tightfitting lid and a toilet seat. Water can be provided by collecting rain from the roof into a tank. Refrigeration can be provided by an icebox, illumination by flashlights, a kerosene or similar fuel lamp, or candles.

    The transition to living aboard can be quite tricky. Firstly, one's earthly possessions must be pared down to the bare essentials, which are all that will fit on a boat.

    Something I learned while living in Japan was the elegance of the Japanese room. To put it simply it is bare with absolutely nothing in it most of the time. To sleep futons can be rolled out then put away again when finished with. To cook, eat or something else that requires a table a small fold away one that doesn’t take up much room can be well designed. Sitting on the floor Japanese style will mitigate the need for chairs or any else for that matter. You soon realise you don’t actually need that much if at all.

    But living aboard makes it relatively easy and inexpensive to get away and stay somewhere else, for a night, a week, or a season, at a nearby anchorage, or, given enough time, halfway across the world.

    While it is by no means for everyone, living aboard is one of the few ways available to people of very little means to live in a city of their choice, own their residence free and clear, never pay a penny of real estate tax, and vacation for as long as and wherever they please, remaining debtfree all the while. It can be much less expensive than living on land, freeing up much time for things other than work, such as providing home schooling for one's children, traveling the world, spending time with friends and family, or just quietly contemplating this crazy world, which is spinning further and further out of control with each passing day.


    Chapter two

    Construction materials and putting her together


    Standard Temporary Fencing is an extremely versatile piece of equipment, ideal for construction sites and outdoor events.

    Manufactured from pre-galvanised steel, these panels come at the height of 2045mm and length of 3450mm. The mesh infill of the panel are also galvanised steel here are some Key Features

    • Made from high quality steel
    • Galvanised to BS EN 10244-2 standard
    • Joints welded using SmartWeld 100 technology
    • Reusable
    • Easy to transport

    Each panel weighs about 15kg and the best part is you can often get them for free. They are designed for temporary fencing for events or projects that once it’s over they are discarded.

    These panels will form the framework for our tiny house boat project. Four can be fixed together with cable ties to make a tunnel of about 3.5M in length and about 2M high. These dimensions can be flexible depending on how you fix the four of them together.

    Once you have them cable tied together, you can get inside and start plastic wrapping the inside which is not as easy as the outside. Spacers made out of thick corrugated cardboard will need to be fixed to several places to start with, this is to get the gap correct for the expanding foam to fill. Aim for at leave 10cm but you could certainly make it thicker if you want more insulation.
    Then start to parcel tape between the spacers you fixed on, this will provide a base for your plastic wrap to stick to. Then start to plastic wrap the inside layer working from one end backwards leaving a hole for you to exit from. At least three layers.
    Once you crawl out seal up that gap so it’s completely sealed on the inside. Then start plastic wrap the outside which is so much easier. You should have a gap of about 10cm between the two layers of plastic wrap.

    Once you are ready for the expanding foam make sure the hole you make to insert the foam can be sealed with strong duct tape once you have emptied the contents inside.

    Expanding foam will keep expanding far more than you expected and will always take the path of least resistance. As long as your two layers of plastic wrap keep their integrity it should fill the majority of the cavity. Once you can see it has stopped expanding you will see areas that need more foam shot in. Again make as small a hole as possible in the outside layer and shoot in the required amount then seal up the hole with strong duct tape.

    Leave the finished structure a couple of days to settle and cure. It may expand or contract a little here and there until it settles.

    Next job will be to cut the entrance hatch and windows. Use the lightest double wall plastic or Perspex translucent material you can get. Use imagination and initiative even plastic bottles or containers could make port holes to keep the weight down.

    A pointy bow section can be made out of wire then plastic wrap again and filled with expanding foam.

    The design of the 1970s water rat gypsy boat was a big inspiration in my design project but this modern boat will have an even better strength to weight ratio. Latest technology building materials and technologies that can produce far superior strength to weight ratio. The entire vessel unladen will be less than 70kg (4x15kg panels and about 10kg foam and everything else) meaning it could be towed by a bicycle or electric scooter. This can be either stored inside or fixed on outside the vessel.

    The wheels can be removed and attached to the chine runners as needed and taken with you so that if you go somewhere that you would like to go ashore you can attach the wheels and take out your bike or electric scooter and off you go.
    The chine runners also act as buffers or fenders as the first point of contact coming alongside something like a riverbank, canal wall or another vessel.
     
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  5. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    Here is where I will build her

     
  6. Quidnic
    Joined: Apr 2020
    Posts: 59
    Likes: 10, Points: 8
    Location: Wales

    Quidnic Junior Member

    Getting the design of the bow right is the trickiest part, what is the most simple easiest ?
     
  7. clmanges
    Joined: Jul 2008
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    Location: Ohio

    clmanges Senior Member

    Sounds like you're looking at an enlarged version of a Puddle Duck Racer (nearly identical to the Bolger Brick). Some people do build their PDRs with chine runner keels, but daggerboards seem to be preferred, and I suspect would work better on a larger boat. There are very few constraints on the PDR's design, and a few folks have made theirs with enough of a closed cabin to be useful as overnight beach cruisers. Check 'em out.

    Puddle Duck Racer - Easiest Sailboat to Build and Race https://pdracer.com/
     
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  8. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    Yes I love the gorfnik and other puddleduck racers just like the Bolger brick

    but mine will have standing headroom


    4 m long by 2.5x25 high and beam

    can’t decide on the bow having a little foredeck or just full pointy bow

    my design will look a lot like a UN peacekeeping APC
     

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  9. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    This is the king of bow I’m thinking about without the central piece
     

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  10. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    My box boat will look more like the Star Trek lander
     

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  11. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member

    Here is part of my blog and why I’m designing and building this tiny house boat........




    Introduction

    Things that cannot go on forever... won't.
    Our entire world is in the final stages of an unsustainable way of life built off the constant expansion of debt. This is the first time in human history that the entire world is printing digital money out of thin air to constantly expand this debt. Unfortunately, this will end horribly for the majority of the world — they won't see it coming until it is too late.
    However, if you are aware, you can prepare.

    Right now, most of humanity is living in utter denial that our way of life is going to end. Our entire way of life, or paradigm, is built off of unsustainable debt that has been passed on from one generation to another.

    We have reached the tipping point — where the debts have become so large there is no way out. We will see the very basis of our economy, the currencies which every country uses, fail in the most spectacular fashion. The implications of this collapse will be the single largest event in human history. The collapse of the currency will upset every aspect of your life. Your job, your savings, your food, your relationships, your safety. Everything.
    If you are like my family, you see this global crisis coming. You see much harder times down the road. You see more food shortages, more pestilence and more unexpected hardships beyond measure. Unexpected for most but not for all.

    Some of us for-sore or even expected, you could say the word prepared for these times. Yes those who were awake to world events called themselves preparers or preppers.

    You can work on being energy, food, water and even housing independent in a smart way that requires very little input for great returns as you will soon find out.

    Reduce your financial footprint.

    Make yourself rich by making your wants few.

    Less coming in and less going out but you still live very well.

    Living in a tiny house boat off grid so you have no rent or bills. Small Solar panels and batteries for small amount of electricity. Wood stove for heating and cooking and rainwater harvesting from the roof to keep your water tanks topped up. Composting toilet and reuse all waste water for edible plants.

    Chickens, rabbits and guinea pigs in moveable tractors where they are protected from predators and can be moved onto fresh pasture for them to eat regularly. These can provide the majority if not all the meat and eggs so you have virtually no outgoings for food.

    Every animal you prepare to eat the entrails can be used as bait for fish traps. The waste from seafood can be used to feed your quail. Seafood waste can be a very nutritious food for quail. Anything you catch in your fish traps that you don’t eat can be given to your quail.
    The advantage of micro livestock is that you can pack up and move with just a few breading pairs at the drop of a hat. They will soon restock their numbers.
    The advantage of a tiny house boat on wheels and your livestock in moveable tractors is that you can pack everything up and move if you want to.
    Guerrilla gardening and living, if you get moved on always have a few back up places in mind. Get together with other like minded people and encourage others to live the nomad OMAD lifestyle.
    We eat only one meal a day. OMAD. High quality seafood, meat and eggs. We loop our own orin as well as rainwater. And live very simple but fulfilling lives.
     
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  12. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    I'm seeing a whole lot of fantasy here. Delightful fantasy, but fantasy none the less.

    So far, you have not even put up a sketch on how this vessel will look and how you're going to fit everything you need to survive in it. It will need a propulsion system of some kind. And with as much windage as you have in mind, you probably aren't going to be able to navigate by oars or a yulo. Any kind of a wind will blow you all over the place.

    Also, you are counting on a steel mesh/foam composite for your structural strength. Who knows? It might work out. But you might have problems with thermo expansion. If the steel mesh expands faster or slower than the foam, on a hot day (or when shrinking on a cold day), your panels may pull themselves apart.

    You do seem to have atleast an intuitive sense of structural engineering, but that is not good enough. You need to do the math. And before you do that, you need to learn how. Otherwise, you may end up with a big pile of mess that kind of looks like a boat.

    I think your weight estimate is off by as much as a factor of three. It seems that you counted only one skin of mesh (you will have two), and you made no weight allowance for the foam.

    Simply putting wheels on this will not work. You will need some kind of suspension system.

    I encourage you to flesh out your ideas with practical considerations, and use your fantasies as a compass.
     
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  13. Quidnic
    Joined: Apr 2020
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    Location: Wales

    Quidnic Junior Member


    The weight is correct 15kg panels x4 = 60kg and less than 10kg for the foam and anything else ie cable ties

    only one layer of panels but two layers of plastic wrap to sandwich the foam

    there will be no propulsion apart from a hobby sail made out of canvas which will never really be used for anything other than very short distance

    It will mostly be pulled or pushed by hand or with a rope

    it will not need suspension of any kind as it will only be moved very short distance on its own wheels just enough to put it on a car transporter or other trailer for moving longer distance

    this is the sort of thing I’m talking about... a floating APC made out of foam
     

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  14. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    I do hope you will film and publish your attempts, it's going to be major fun. First seeing you spray foam from a rattle can between two flexible surfaces, then when you climb into the finished product and the fence wire cuts trough the foam under your weight. There are other funny moments, but I suspect you won't have to film them.

    Anyway, the weight is not correct, rattle can foam has a density between 20-30kg/m3, one square meter of 40mm thick foam will weigh between 0.8-1.2kg. One of those fencing panels has 6.8 sqare meters, so presuming you can manage a uniform thickness the foam will add between 5.4 and 8.16kg per panel. With four panels we are talking 22kg of foam in the best case scenario, and that is wishfull thinking, 10kg per panel is more realistic, and still on the light side.
     
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  15. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The cost of materials is much higher that that of exterior grade plywood. The semi-water resistant spray foam is about $6.50 a can; 3/8" exterior plywood is about $30. The price of fencing is quite high too, and they are not made for single use. Also, there is no way the foam will fill the voids completely with this plan either. The plastic wrap will stretch and it will end up being a bunch of foam blobs. Structures made with injected foam have stiff and strong molds to hold the shape. It is not a realistic plan, or a cheap one either.
     
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