When it comes down to the essentials for survival,
我们一般会想到：食物 水 庇护所
we usually think of the basics: food, water, shelter.
However, for the 75% of adults in the world that have less perfect vision,
corrective lenses might be almost just as important to them.
For something so crucial as allowing yourself to be able to see,
how hard would it be to make them yourself?
Well, that’s why I’m trying do.
Starting from the most basic materials,
I’m gonna attempt to make my own prescription eyeglasses.
But before I begin, I wanna reach out to an expert
with some experience in this endeavor and get some advice.
So I looked up Lewis Dartnell, author of “The Knowledge”,
where he attempts to provide all the information you need to rebuild society from scratch.
While researching his book,
he went through the process of making his own glass from scratch.
Since I’m attempting to do something similar,
I sought out his advice.
要制作玻璃 你需要二氧化硅 可从沙子里提取
So for glass, you need silica which you can get from sand.
You need something to help you melt that silica at reasonable temperatures in a kiln,
and that’s called a flux.
And you can use soda ash or potash as a flux,
which you can get from seaweed.
And lastly you need lime,
which you can get from coral or sandstone or chalk.
So it turns out all of the main ingredients for glass, you can collect on exactly the same beach.
And I went to a beach in Norfolk in East England,
and I collected all those things from the same place.
And over the course of a day,
made glass from scratch, from the stuff that we’ve harvested from the natural environment.
A little bit different for me, because I’m located in the center of continent.
Getting the sand and the limestone shouldn’t be a problem,
but I don’t think I can get any seaweed or anything like that.
Tell me more about the potash.
嗯 与其烧海藻一类的东西 不如烧硬木材
Erm, rather than burning things like seaweed, you can burn hardwood timber.
And that timber collects potassium carbonate
or potash as it was known through history.
So it’s a slightly different chemical, slightly different compound,
but it performs exactly the same function as a flux
for helping to lower the melting point of your silica to make a glass.
Thanks for help, Lewis.
I think that should give me a start in our direction.
Excellent stuff! Good luck with it, Andy.
And definitely let me know how your making from glass project goes.
I’d love to see the results.
With Lewis’ suggestions,
my first step is gathering the raw items I’ll need:
sand, limestone and hardwood ash.
Starting with the sand,
I tried to find the whitest sand available near me,
off the bank of the Mississippi River.
And then strained out any extra pebbles or other debris
that might have been mixed in.
On the way back, I managed to find some limestone
and collected a few rocks.
Then later I pulverize them into a pocket.
That just leaves one last ingredient – the hardwood ash.
As a safety note, if you decide to use an accelerant to start a fire,
make sure you know what exactly you’re using.
Because apparently some fuels can be more explosive than you expected.
With my three ingredients collected, I turned to Michael,
a glassblower who agreed to help me,
to test out my ingredients and see if this was even gonna work.
What I got back was something very far from actual clear glass.
At this one, I realized my mistake.
In haste, I’d forgotten the very important step
of actually separating the potash from the rest of the ash residue.
So I’m gonna need to get some more ash.
This time I very cautiously and slowly built up the fire.
To extract the potash, I first soaked the ashes in water.
The coals and the lighter will float to the surface
and can then be skimmed off.
The potash or potassium carbonate will dissolve into the water
and all the other unwanted minerals from the ashes will sink to the bottom.
Then I just need to boil the water down,
until I just have the powder of the potassium carbonate left.
So I spent about 30 hours boiling water now
and boiled at least 20 gallons of water.
End result of all that is this.
And weighing it out, it is only 182 grams.
That is… maybe enough.
Unsure about the quality and quantity of potash I produced, I visited Michael.
We performed one more test of my ingredients.
He carefully measured everything out to the proper proportions,
mixed everything together,
then he heated the sample to see if it produced anything close to glass.
That’s a good test.
Confident in the results, we can move on to a full-size batch.
But first, since we’re only gonna be able to produce
a small quantity of glass because my limited supply of potash,
I decided to do a practice round with some of Michael’s regular glass.
Once cooled, I used a diamond tip drill bit
to cut a bunch of disks out of the bulb.
Next, the hard part, shaping the lenses into my correct prescription.
Using a series of abrasive wheels,
I slowly ground my lenses into the correct shape
and then polished them clear again.
Because I’m nearsighted,
the lenses will need to have a concave shape.
Fortunately, since I started with a curved glass from the bulb,
all I need to do was grinding the outside face a little bit shallower
to achieve a concave lens.
The best way I found
to measure the curvature of my concave lenses
was to use a laser pointer.
Because a concave lens is refracting light outward,
凹透镜的焦距 也就是聚光点 在镜片的后部
its focal length where the light converges is actually negative.
Therefore I figured I can measure the point where the light diverges as
being twice as far than if they had been parallel.
The inverse of this number should then be my focal length of my lens.
In my instance, I measured a half-inch from the center of the lens
and then found out at which distance the lens would refract it to be a full inch off.
Thanks my visit to the optometrist Dr. Seaver before,
I know what focal length I need to be at to match my prescription.
However, I’m only able to shine the laser pointer
through the lens after it’s been polished.
So this makes it a lot of guess and checking,
then having to redo all of the polishing once again.
If the focal length is still longer than my prescription,
that means I need to keep going and grind it down even further.
If it’s too short already, that means I’ve gone too far
and I’ll need to start all over again with a new lens.
After spending the better part of a whole day grinding my lenses,
I now have the completed ones.
So I’m just gonna measure one last time,
make sure they’re right and compare them to my actual glasses.
Well, my method is obviously not the most accurate.
As far as I can tell, I’m pretty close to spot on with my lenses.
Now that I’ve gotten the hang of grinding my own lenses.
I’m ready to attempt it with the glass.
I’m actually making it from scratch.
Because we’re working in such a small commodity,
I didn’t have enough to blow a bubble.
Instead, we were going to pour it into a flat mold.
Once we kept it thick, we could slump it over a form.
And that gets you halfway there
and then you’d have to grind out by hand of concave surface.
I’m going on and on. It’s kinda work at it.
You can see it’s just starting to kinda form together there on the surface.
It’s pretty cool.
After heating it in the kiln for several days,
it was finally ready to pour.
Pretty gnarly stuff.
Once board, it just needed to cool overnight in the kiln,
and then I could apply the same grinding technique to these lenses as well.
But in the meantime, I’m gonna make the frames
to actually hold the lenses onto my face.
After the struggle of making the glass,
let’s try materials that’s a little simpler – wood.
After felling my tree,
I chopped the tree trunk into some workable size boards.
But because this tree is freshly cut, it contains a lot of moisture
that will eventually dry out of it and cause it to crack and break.
Generally wood is only ready to be used,
after it’s been left to fully air dry for up to a year or two,
or if it’s slowly baked in a kiln for up to a month.
However, I don’t quite have that much time to wait,
So I’m just gonna throw it in the microwave.
By microwaving it in short bursts
and carefully measuring how much moisture weight it’s lost,
I can slowly dry these boards out in about an hour.
Once there is no longer any measurable amount of weight loss between bursts,
I know it’s dry.
However you do need to be careful,
because if you overdo it, it’s gonna start on fire.
With my now dry wood, I can make my frames.
However, I still have my practice lenses and a fair amount of wood,
I thought reaching out to a woodworking expert
and see how great a frame he can make for me.
So together with the lenses and my microwave wood,
I mailed them to David at Make Something
to see what he could come up with.
Check out his video on his channel,
to watch the entire process he goes through
to make me an even better set of frames.
So I just got the package back from David.
咱们来看看他做的眼镜架 哦 哇
Let’s see how his frames turned out. Oh, wow!
很美 哈哈哈 哇 看起来相当不错
Nice! hahaha… Wow, it turns out pretty good.
Ooh, it’s a little big.
All right, wow!
That is pretty good.
This is awesome.
干得好 大卫 眼镜架很不错
Great job, David. This frames turned out great.
My glasses are a little bit different, particularly the glass.
So I had a little bit of an issue – that is not the clearest stuff.
If you look closer at it, there are parts of it
that are trying… trying to be clear.
Erm… I can see some light through this,
but I cannot see anything.
So in that regard, my glasses were not the best of successes,
at least in making them clear.
But if I’d be able to get them clear,
I’m sure it could have gotten them
actually prescribed to my eyes like these.
These are pretty close.
Overall, I can see a lot better than I could without them.
But I’m gonna check in with Lewis to see if
he has any suggestions on how I could have done this better.
好吧 路易斯 这就是我的眼镜成品
Alright, Lewis, so these are my final glasses.
Andy, can you even see me?
Can you see anything at all through those glasses?
I can see a little bit of light. That’s about it.
You can tell if it’s night or it’s day.
You… I think you’ve nailed invention of spectacles in history.
Well done, Sir.
So from my point of view, what I can see here all in two things:
It looks a little green. It looks quite tinted green.
And it looks quite opaque. It looks almost frothy in there.
It’s called “seeding”.
I think there’s a lot of tiny bubbles that have got caught
in that glasses you’re melting it in your kiln.
The sort of things you can do trying to solve that,
erm… maybe trying to leave it in the kiln for a bit longer.
So that the glass is molten,
and it gives a longer opportunity for the gas to escape from that glass,
the bubbles to escape and not get trapped when they resolidifies.
Maybe try repurifying potash you’ve got
because that I said the key component is that flux
that help to reduce the melting point from viscosity of the glass,
also help the bubbles to escape as well.
And I think the reason you’ve got a bit of a green tint there
is maybe your sand, your silica had some iron impurities in it,
will make the glass come out so green-tinted
which, you know, I mean that’s fine for a bottle of wine
but I think for your pair of glasses,
erm, it’ll be a little bit irritating if it’d been green whole time.
You’re looking at the world through green tinted glasses.
So what would you recommend I’d make next?
Oh now that you’ve made a pair of spectacles
and to be honest, I use “spectacles” in the broadest sense of the word.
I reckon you should step up a bit.
And the next thing you should try
is to use your lenses in combination with each other
and make something like a telescope or a microscope from scratch.
And maybe see if you can use your telescope
to see the moons orbiting Jupiter,
which Galileo was able to see over 400 years ago,
when people first started turning telescopes towards the heavens.
So I’d love to see if you… if you could pull that off.
Definitely I would try that next.
好 你接受挑战了 好的
Yeah, challenge accepted. Okay.
Well, let’s know how it goes.
And I’m looking forward to hearing back from you again.
Also thanks to both David and Make Something.
Be sure to check out all of his amazing wood making videos.
As you can tell from my glasses, he does some really amazing works.
Be sure to check out his videos. They’re quite good as well.
And also thanks to Lewis for his assistance and guidance with this.
Be sure to check out his book “The Knowledge”.
It is a really amazing book and something I am probably gonna be
referring back to in future episodes.