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16

There is another not mentioned way to achieve flotation. My kid discovered it today with his "water bat": surface tension. The long flat wings did the trick : ) It is not exactly due to the buoyancy of the bricks themselves as wanted in the question, but might help as a complement. For more on the Physics underlying: Surface tension


15

There are a number of Lego Pneumatic sets with airtight tubes, valves and switches which could be put into use with fluids. One is 9641, Pneumatics Add-On Set. Bear in mind that the pneumatics sets can command a much higer price than those sets with a similar number of parts, and buying individual pieces can also get expensive. Have a look at BrickLink to ...


14

The Atlantis Submarine Voyage ride at LEGOLAND Windsor has almost 100 models (albeit glued together) submerged in a 1,000,000 litre tank with 'upto 50 species of rare sharks, rays and tropical fish'. If LEGO bricks can withstand those conditions, I think you'll be fine. Most of these models are quite large (and heavy), so you may need to weigh down or ...


12

I would try liquid latex (liquid frisket) which you can buy in most art supply store. This will not damage the bricks and is easy to peel off. You can apply it using a cheap throwaway brush, either in between the bricks (like a cement wall) or as a thin transparent layer on the whole hull. I recommend the second method because it's fast, straight forward ...


11

In my experience, this doesn't work very well. The gaps between LEGO bricks are too wide to hold water. The water will be contained for a short amount of time, but it will eventually leak out through the cracks. Here's an experiment showing how your first example works. Notice the water leaking out the crack in the bottom right: The leak continues to grow: ...


10

My children play with the lego fishing boat (see picture) in our bath tube. This design does have a serious flaw (imo). Even if there are very small water waves in our bath tube, water enters the boat which then becomes to heavy and sinks. So if you are planning to built your own lego boat i would make sure the sides are high enough to prevent water from ...


7

Yes, if built carefully. When I was a kid I made a number of lego boats to play with in the tub, and later in the pool. The main thing I remember was to make the hull upside down and out of at least two interlocking layers. Lining the inside with plate also helped.


7

Basic LEGO elements won't get damaged by water, however depending on the condition of your water source, some residue may build up on the elements after prolonged immersion. So if you are thinking about keeping them immersed for a longer time, I would suggest using distilled water.


6

I did something like this once, I cut down a butter tub and built the lego around it, with plates hiding the top edge. It worked very well, but the stale tea that I used for the swamp stained my bricks. I can only think that a brick-built wall with a plastic carrier bag secured by a plate layer at the very top would be your best bet, as none of the bricks ...


6

Most Lego pieces sink. Some of them will float briefly if they have air trapped inside. Almost any construction of Lego elements will sink as there are gaps between pieces. There are some boat pieces that are designed to float, such as the Police Patrol Boat set from 2016. A Brickset list shows some other boats that float.


6

The method they used to secure the battery/controller was to wrap it in a sealed plastic bag, something similar to this could be done for the motors. It would be more difficult since you would need a water tight bearing for the rotating shaft to exit the sealed bag. These bearings are complicated and will still always allows some small amount of leakage. ...


6

The Lego pneumatic valves are not great for (liquid) fluid experiments as the valves dissipate the return path to atmosphere, so they p*ss water out. And the pneumatic hand pump spring and metal core of the regular pistons rusts in a few days. It's about 15 years since I learn't this :-)


5

I would tend to suggest another non-waterproofing solution - build something to hold your ship from underneath, that will safely rest on the bottom of your pool. Of course, if you don't want it to show on the picture, you'll have to be extra careful about how you do it, but I think it's the simpliest solution. What I would do is buy a large plexiglass ...


4

Maybe you don't need to waterproof it. If you are able to fit a block of foam (eg. extruded polystyrene) inside the hull, that will probably be enough to ensure flottability.


4

Since you are willing to use a non-LEGO frame to hold the roof and glue to fix all together, I would recommend buying baseplates in bulk and gluing them onto a wooden frame as if they were shingles. If the gradient and the overlap (vertical between rows and horizontal between individual plates) are correctly matched, the rain won't get inside. For more ...


3

I admittedly don't have the 46x46 = 2116(!) 1x1 clips to properly build this, but I was able to build a small sample to replicate the problem. Because this construction technique eliminates the natural tiny gap between elements, you can't easily reinforce it just by attaching plates and bricks to the underside. This construction is essentially "out of ...


3

This image of the same model shows that the whole set sits on a frame of bricks. In the inside, you could place bricks underneath wherever necessary to attach the water plates (not only 1x... but maybe 2x10, or several 2x4 in a row). They are invisible, so color and type don't matter. If this row of bricks reaches from one side of the frame to the other, it ...


2

Some fairly straightforward physics is your friend here: To determine if something will sink or float in a given medium, you need to know its density. If the density of the object is less than the density of the medium it will float. Standard pool water would have a density around 1g/cm3, salt water is higher (depends on the amount of salt in the water). ...


2

No, the LEGO Mindstorms EV3 is NOT waterproof. Any electronic product that is capable of being immersed in water will clearly state in the packaging/manual the level of water protection provided. This may be in the form of an IP Code: Ingress Protection Marking, classifies and rates the degree of protection provided against the intrusion (including body ...


1

The LEGO bricks themselves will be fine, but if you're adding fish and turning this into an aquarium setting you may need to perform some periodic maintenance on them to keep them looking nice... but lots of people have used LEGOs for aquarium decor with great results.


1

I suspect that water leaking through the hull will not be the real problem you need to solve. Granted, I haven't seen a photo of what you have built, so I might be wrong. I think the real problem you might have is that a Lego boat will be quite a bit less massive than a wooden or steel ship with the same proportions. If you go look up some of the old ...


1

Try spraying the inside with plasti dip, it goes on like spray paint or you can use a cheap paint brush, then you can peel off as one whole piece. Best of all it comes in many colors! Get it here www.plastidip.com they also sell it at most home improvement stores.


1

Styrofoam bits trapped in brick-built chambers might work Ok to keep structures afloat.


1

Yeah they float but make the hull wide not narrow as it will stay up right if you make the hull wide. Narrow means top heavy. I first started making LEGO boats now I make home built boats. And no need to be water tight for LEGO just get more surface area. Who knows you might even be able to make a cruise ship that floats.


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