[Captions by Y Translator] YouTuber Mark Rober has a cool video
where he makes a giant fluid sand bed out of a hot tub.
In the beginning of that video,
he also shows his small prototype sand bed
and we're going to be showing you step-by-step how you can build one
of those for yourself.
[Music]
If you are the kind of person who likes watching cool builds,
and engineering on YouTube,
then you probably know who Mark Rober is,
and you've probably seen his video where he took a hot tub,
filled it with sand, ran air through it,
and made just a fluid sand bed that you could lie down inside.
It was very cool.
But he started out the video showing a smaller version that he built
as a proof of concept.
I reached out to Mark, and he said it would be cool
if I did a video showing you step-by-step how to build one
of those smaller fluid sand beds for yourself.
Here's the basic plan, we're going to set up a series of tubes
and corners that fit inside a box, and pressurized with air.
The piping will be full of very small holes that run air
into the sand turning it into a fluid.
Here are the parts that we are going to need to build this.
We have our 1/2 inch pipe, right here, we have about,
15 feet of it.
We won't use all of that
but it's a good amount to start with.
We have four, 1/2 inch elbow pieces.
We have eight, 1/2 inch T pieces
that are smooth in all three ports.
And we have one, 1/2 inch T piece
that's threaded in the center port and just a push fit on the sides.
We've got a little bit of metal hardware as well.
This is a bushing that goes from 1/2 inch to 1/4 inch
on the inside.
A connector that's 1/4 inch on both sides.
A small 1/4 inch ball valve and a 1/4 inch fitting that attaches
to our air compressor.
We also have this plastic tub that I bought at Home Depot for about 6 bucks.
This size tub ends up working out really well,
and the bottom inside measurements are about 18 1/2 by 12 inches,
and that would be 47 centimeters by 30 and 1/2 centimeters.
Now, we need to cut several pieces out of our 1/2 inch pipe.
First, we need five pieces that are 16 and 1/4 inches long.
If you want to get really precise,
that's about 41 and 1/4 centimeters.
You don't have to use one of these pipe cutters for this
but it really is nice.
With those five pieces cut,
the next two pieces are two that are 7 inches long just under 18 centimeters.
Finally, we want 10 pieces that are 1/3 quarters of an inch long,
which is about 4 and 1/2 centimeters.
While he was coming up with the design, Mark did a lot of trial and error,
and he found that the way to get the best air flow
through the pipes was
that each of these long pieces, which will be going across our box
will have a series of small holes running
along the bottom.
There will be pairs of holes at 90-degree angles apart
from each other and spaced out about every 2 and 1/2 centimeters
all the way down the pipe.
To get the lines of where I'm going to drill the holes,
I've marched two spots on the end of the pipe that are about
90 degrees apart from each other
and I'm now going to line these up just on the table,
and trace a line down the whole pipe.
We've got our lines drawn our pipes and now we need to mark out the spacing
for where we'll drill all of the holes.
Every 2 and 1/2 centimeters is the goal.
We've got 80 marks on the pipes,
and we need to drill each of them on both sides.
So that is 160 holes that we need to drill into these pipes.
For that, we are going to be using a drill press
and a 1 millimeter drill bit.
It's very small drill bit and it helps prevent any
of the sand getting up through the hole and ending up inside the piping.
[Music]
Alright, we've got all five pipes drilled out.
If we block one end and blow on the other side,
we can feel all of those holes just pumping air out.
Now we have those, and it's time to start
connecting all of our pipes together.
I'm going to put together all of one side,
and then all of the other side,
and then I'll go about gluing all of the pieces in between.
Making stuff out of PVC.
Guys, my album drops next month.
It's gonna be so good.
Now, this side can be a little bit tricky
because we kind of need to push all of them on at the same time.
But, I think we can make it work.
[Music]
So now we've got this lattice with hundreds of holes
along the bottom that will be spraying our air out.
There is another modification I do want to make.
We're going to take that same drill bit and add a few more holes
through all of the supporting structure
so that all of the air gets blown all the way
to the sides of the container,
and we don't just have it in the middle.
Our air is going to enter into this through these two T pieces,
and you can see that this mostly fits down in there,
but it's just a little bit too wide, and that's intentional
because we're going to drill two holes in the bottom,
and fit it in through those holes.
This 1 and 1/8 inch spade bit we're using is just barely larger
than the pipes we're trying to fit through the hole
so it should be pretty snug
if it cuts a nice clean hole.
We are cutting on to sort of a curved edge.
So there's a very real possibility that it won't be perfectly smooth.
[Music]
Alright that fits.
It's pretty snug, holds itself into place.
There is some gap around that, we'll fill and plug that up.
That's working.
[Music]
Takes a little bit of effort squishing it down
forcing it into place.
But, once we get it down in there, it fits quite snug.
You can see it's just right up against all of the edges of the tub,
which is just what we want.
A little bit of space down below that'll help the airflow up
through it better.
Now, let's take some silicone caulking.
Mix it with a little bit of water, and then just press that
around these seals.
It will basically be Proto Putty although,
we won't add the cornstarch,
and it should just keep a nice tight seal around there.
There's not going to be pressure pushing out on these
so it doesn't have to be a high pressure seal.
That's just to keep any of the sand from running out those holes
while it's nice and fluid.
With our box glued in place,
it's now time to add the rest of the hardware.
We're going to use our other two small pieces to connect two more elbows.
Those elbows will connect to our seven inch pieces,
and that will connect to our T with the threaded spot,
our T with the threaded spot will have the bushing,
the connector, the quarter inch ball valve,
and finally the piece that connects to the air compressor.
Now, we're going to turn the compressor on,
and while that's charging up,
we're going to load in the first type of sand.
We've got four different types of sand that we're going to try out
to see which one's work well with this and see which ones don't.
First up is play sand.
This is just your normal playground stuff.
It's not super consistent, there's a lot of size variation with it.
All we have to do to add pressure is open the valve
and we actually have control if we just open it a little bit.
We only have a little bit of are getting through.
If we open it a lot, a lot pours through.
[Music]
Weird how little it works in the middle, though.
That's not putting up much at all right there.
[Music]
So the playground sand works a little bit.
It's very very dense while it's just sitting in there
without any air flowing through it.
You can't really pass your hand through it very easily,
unless you're just like digging down in.
So, playground sand is not so good,
it's very uneven and even the finest grains of the sand aren't that fine
compared to some other types.
So playground sand, I don't know,
I'd give this like a C-grade, really not that great.
Let's move on to the next kind.
Next up, we have this Quartz mineral filler,
and this is usually designed for just mixing into cement to make concrete.
It's a fairly coarse grain, so, I have my doubts
that this stuff is going to work very well,
but I haven't actually tried this kind.
Here goes.
[Music]
All the way open and nothing.
Now, we'll fill it back up into the bag.
So now we have what isn't actually sand.
This is actually a glass bead material.
It's used for sandblasting.
Mark in his video used glass bead too.
I don't know if we're using the exact same grain, but it is a very small, very fine,
and fairly uniform grain, which is really what you want
for one of these beds.
[Music]
That was a lot of bubbling and I barely had this open.
Whoo!
That is crazy already.
So, even when it's closed, this stuff is fine grain enough
that I can move it, and kind of swirl it pretty easily,
but it does stop my hand.
Doesn't go anywhere and opening just a little bit.
I can now just push my hand right down through that.
Let's open it more, to really get it bubbling.
[Music]
Look at that, it's just got like waves back and forth.
[Music]
Beautiful.
This is a cool way of illustrating a concept
that when you're in a boat, and you're in the ocean,
if you ever see water that's bubbling,
you're supposed to avoid it.
A boat floats on the water because the boat plus the air
in it has a lower average density than the water underneath it.
However, water with are bubbling up through it has a lower average density
than regular water,
and you can hit a critical point,
where your boat, even with nothing wrong with it,
can just sink right down into the water air mixture.
If you think of this sand as water and the air as air,
you can get something similar happening.
These pieces of plastic, they float on top of the sand.
However, once there's air floating through the density of the sand goes down
and these pieces of plastic,
they don't survive very well.
[Music]
And your ship has sunk.
[Music]
"Random fact, it's been estimated that there are approximately
seven quintillion, five hundred quadrillion grains
of sand on all the beaches in the world.
That's a "75" with 17 zeros after it."
[Music]
Alright.
Let's see if our colored sand works.
[Music]
Yeah.
I'm just gonna turn it off again.
That's already starting to mix so much.
Alright, I'm going to turn it on.
It's going to get fluid
and I'm just going to put my hand through it.
And it's just going to get mixed up fast.
[Music]
The fluid sand bed is not that hard to build.
It doesn't take that long and it doesn't cost that much.
I think, by far, your biggest expense
is going to be if you want to get the really good sand.
That's the superfine glass beads that are used for sandblasting.
That bag did cost me 30-35 bucks,
but it works by far the best.
But thank you again to Mark Rober for his design,
and saying it's cool
if we make a video showing how to build the small one.
If you guys have not seen his video where he turns a hot tub
into one of these things, you got to check it out.
He's like floating in it, and there's like six people
in it at once, it is super cool.
I also thought it was super funny watching the up-close slow-mo
of the sandy erupting into being a fluid.
It really looks kind of like a landscape that
you're seeing from a drone shot above but we just took a camera and like
put it down in the sand practically.
It looks really fun.
But it just starts moving a little bit.
The sand is really light reflective so you can see like little points
of light starting to appear
and then the whole landscape just starts...
just like that.
I hope to see some of you build this.
And if you do, tag us on Instagram or Twitter,
or wherever you like to post the photos
and we'll check it out.
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