Will It Lens? Table of Contents
Welcome, all! Here are links to everything in the “Will It Lens?” series.
- Part 1: introduction, melting pennies, dimes, toothpaste, Tylenol, milk, chalk, gourd, can.
- Part 2: equipment upgrades, CDs, disposable silverware, brass penny, burned pennies.
- Part 3 (Food Edition): popcorn, grape, kumquat, Frosted Mini Wheat, jelly beans, Reese’s Pieces.
- Part 4: wood, quarter, soap, dishwasher detergent, bacon, egg, honey, seashell, almonds, gummy bears, M&Ms.
- Part 5 (Temperature Breakthrough): marshmallow, peeps, copper, iron, sand, glass
- More to come
sooneventually!
- Gallery of all pictures: This contains every picture we took. There’s a lot of junk in here; the good pictures are in the blog posts above.
FREQUENTLY ASKED QUESTIONS AND SUGGESTIONS (updated)
- Can you melt glass?
This surprised us, but yes! Normal glass is more properly called “sodalime glass,” which has a much lower melting point than pure silicon dioxide (which we originally thought glass was made of, and which we haven’t been able to melt yet). However, we have trouble melting clear things because they don’t absorb the sunlight. Nonetheless, we melted a dark brown glass in part 5.
- Can you melt sand?
Kinda. The sand we tried is a mixture of quartz, feldspar, and iron. We can melt the last two, but we haven’t melted quartz yet. Look at part 5 for more details.
- Can you lens electronics?
We probably could, but we don’t want to because the fumes are really noxious. There’s lead and other stuff that’s terrible for your lungs in there.
- Can you use a second lens to focus the light even more?
No, that’s not how optics works. For a slightly more thorough answer, see the Light Sharpener FAQ over at cockeyed.com.
- Where did you get the lens? How much did it cost?
I think we got it from here. When we ordered it, I think it was about $120, plus shipping. If you include the wood for the frame and stand, the welding goggles, and the skillet, we’ve probably spent over $200 on lens-related stuff so far.
- You should lens something that will burst and explode all over the place!
That would be very entertaining, but we need to clean everything up before lunch is over, so we’re not doing anything too messy in the foreseeable future (no unopened pop cans, no aerosols, etc.). If we ever take the lens out to the middle of the desert, we will consider lensing messy things.
- You should lens an iPhone, iPod, or other hip status symbol.
First, see question 3 about electronics. Then, remember that we’re paying for all of this with our own money. We’d prefer not to lens anything that costs more than a couple dollars. Everything we’ve tried so far has cost under $1 each (almost everything is under $0.25 each).
- Isn’t it illegal to destroy money?
Not unless you do it with the intent to defraud someone. Remember the last time you went to the zoo? You probably saw one of those machines that will take your penny, flatten it out, and stamp an image of a penguin or something on it as a souvenir. Melting a penny is no more illegal than one of those machines.
Other articles that link to this series:
Working hard
Nice to know you Google lot are working hard on all the bugs and stuff!!! :(
Nahh, I’m just jealous. That looks really fun and I want one. Keep it up!
And I’m aware how much this sounds like a Viagra advert…
Well, that was a highly fulfilling post xD
Videos!
Post some videos of your work too :)
Also, how hot would it need to be to melt your average sand?
Too far? lol
Should try some sausages. And an egg inside the shell. (do with caution, of course, since these are likely to explode)
Re: Videos!
Sand is typically silicon dioxide, which melts at 1996 K. If we can’t melt copper at 1356 K, we have no hope here.
I think you’re right that an egg is likely to explode, and we don’t want to egg our own office. So, maybe some day if we move the lens away from buildings, but not in the near future. However, an (empty) eggshell is already on our list.
Re: Glass
If the glass is clear, it won’t absorb any light, so it won’t heat up. But if it’s somewhat opaque, like a beer bottle, it might work. “Traditional” glass is silicon dioxide (aka quartz, aka sand), which melts around 1996 K. If we can’t melt copper at 1356 K, we have no hope of that. But I don’t actually know what tinted glass is made of; perhaps the tinting material melts at a much lower temperature. I’ll add beer bottles to the list.
You should one-up the Mythbusters and lens a boat. :)
Mirror bounce
Bounce the beam off a mirror that’s laying on the deck such that you can heat a pan from underneath. Such an arrangement should make it possible to cook bacon, pop popcorn (put a Jiffy Pop on the pan to disperse the heat), or pretty much anything else.
Re: Mirror bounce
*blinks* Wow, why didn’t I think of that? We already have mirrors purchased, and it would also solve our problems with the focal point sometimes being in the ground if the sun is too high overhead. We’ll definitely try this out!
Re: Mirror bounce
An extra note of caution here. A friend was working on a car and had set a mirror on the seat without thinking about it (it was flat) when he went to get some lunch. When he got back to working on it a few hours later there was a burn line in the ceiling material in a nice arc as solar progression moved the source. Some points along the path were more heavily scorched due to variances as the windshield curved more dramatically (obviously the focusing mechanism). So, be sure to create a No Go Zone as welding goggles my not be sufficient if you are downstream past the focal point. Although, you might get a more intimate appreciation of the smell of singed hair and the feel of instant sunburn. :D
You might also take a look at the flight path from Moffett. Sure, it would be well beyond most problems but you are talking about an amplified signal mirror that might have an adverse effect on some poor Navy pilot who happens to glance over at the wrong point in his flight path. :(
You guys are having all kinds of great fun. Lots of us wish we could join you. I’ll have to look into getting my own lens!
Re: Mirror bounce
I built one of these a while back. My kids and I and gathered neighbors made perfect popcorn by putting the popcorn and oil in a cast iron pot on some bricks and then focusing the beam on the side of the pot. We did eggs on a cast iron pan, by heating up one side or the pan and then moving he lense over the egg quickly …worked great. I’ve heard you can enamel powdered glass onto copper (usually enameling is an art form done in a kiln). we plan to try this once it warms up again this spring.
Re: Mirror bounce
You need to talk to Dustin, being able to change the direction of the beam is one of the reasons why he bought the mirrors :P
raku?
If you can get about 1000 degrees (~1274K) then you could fire some ceramics. We fire earthenware pottery at those temps at our studio. I imagine you could get some funky glaze effects on bisqued ceramics (if they don’t just break) due to the temperature variations.
Could you lens a small lens to get a better focal point? What’s the smallest spot you’re getting so far?
Re: raku?
Doesn’t it take several hours to fire clay? We don’t have that kind of patience, particularly when we can only fire a square inch of the clay at a time and we’ll have to keep adjusting the lens as the sun moves. I’ll keep it in mind because it’s a very creative idea and we can actually get to those temporatures, but I doubt we’ll actually do it.
We can’t focus it further with a second lens because the incident light is not parallel (for more of an explanation, see the light shapener FAQ at cockeyed.com. Our focal area is about a square inch.
Re: raku?
http://www.garyrferguson.com/justraku25.htm
I was thinking about maybe small, broach sized pieces of bisque. Basically you’re just melting glassy mixes of chemicals onto the surface of the pre-fired clay.
Re: raku?
Ah, thanks for clarifying! I know very little about clay and ceramics. I’ll bring this up with the group.
how hot is it?
http://en.wikipedia.org/wiki/List_of_elements_by_boiling_point
just to add
try some liquid nitrogen.
Re: how hot is it?
We think we can boil zinc, so we can get to 1180 K. We cannot melt copper, so we can’t break 1356 K.
Stirling Engine
Have you considered placing a Stirling engine at the focal point?
http://www.youtube.com/watch?v=fUrB7KRvxUk
Re: Stirling Engine
We have considered it, but right now it’s a pipe dream. Building the frame for the lens is about the height of our construction prowess; we don’t have the skill to build a Stirling engine. However, it is something we’d eventually like to try, if we find someone with experience building stuff like that.
Cooking surface ideas
It seems like you’re having trouble getting even and consistent heat at temperatures appropriate for cooking. Since you weren’t able to melt the copper pennies, how about using a copper plate. Use the lens to heat one end of the plate and place your items to cook on the opposite end. Obviously, the cooking temperature will decrease with further distances from the heat source. Being a good conductor of heat, copper should heat up quickly, transmit the heat well but allow you to control it.
Solar
I just realized this would be an amazing experiment in developing a Solar Powerhouse. Hope this happens.
Have you tried glass yet?
We use a lens just like that to make glass jewelry. We have also posted some movies :)
http://www.sundropjewelry.com/
Steam Generation
Hey guys. Could you possibly figure out a way to either a.) Generate power via steam and post a graph online. Kind of like the Mark Hatfield Marine Aquarium in Oregon has a graph of their solar power output. OR b.) Achieve sterilization temperature (121C) and pressure (15PSI) in a controlled pressure vessel? Possibly a reconditioned air cylinder.
If you can make something light or cheap enough this would be great for field sterilization of surgical instruments for third world countries or after disasters where traditional steam generators aren’t functioning. I realize it would only be helpful during sunny times but it seems possible to make something portable and fairly lightweight. I’d like to see if you can sterilize some bacterial cultures using some solar power…I’d be happy to send you media/cultures to practice with.
I like the idea of reflecting the light off a mirror and heating a copper bottomed pan. Just don’t burn your hand sticking it into the beam.
Re: Steam Generation
We don’t have the mechanical prowess to build a steam engine (we could barely make a wooden frame).
As for sterilization, that’s a fascinating idea! We can definitely break 121C. 15 PSI is roughly 1.02 atmospheres; would it be OK to just have it at ambient pressure? I’m not too keen on heating pressurized things because I’m afraid they’ll burst open and throw shrapnel everywhere (but perhaps this fear is unfounded; I haven’t looked into it seriously). As for cost, our lens was something like $120 retail, and you might be able to get a discount buying them wholesale.
Re: Steam Generation
Ambient just won’t do the trick for sterilization. It’s the heat resistant spores that will get you. As for fear of heating things up, think of it this way: Have you ever made your own jam? There’s a pressure cooker on the stove, boiling hot and pressurized. In fact, I bet you could find a heavy duty one at a thrift store and buy a new gasket if it looked old. Fire it up on your stove at home to test it out and you’ll see it hold the pressure.
Then it just becomes a matter of regulating the heat input from the lens reliably (smaller lens might work too making it cheaper?) to maintain the correct temperature and pressure for 15 minutes. If you guys give it a shot, I’ll be glad to suggest some things to sterilize and if you send it up here I’ll streak it on a plate and see if anything grows.
Re: Steam Generation
I’ve never made jam, nor have I used a pressure cooker, but you have assuaged my concerns.
Our lens is probably oversized for the job, and you’re right that getting a smaller lens will lower the cost. Looking on eBay, you can find some that are under $100 including shipping.
I assume it’s alright if the temperature is higher than 121 C and the pressure is more than 15 PSI. It’s hard to do stuff reliably with the lens, and there’s no way we’d be able to hold the temperature steady. but if we had a thermometer on the side, it ought to be easy to keep the temperature somewhere above 121 C.
The one question I’m not sure of right now is how much heat dissipates into the air. We can easily get tiny areas to several hundred degrees C, but we haven’t had problems so far with the handle of the skillet heating up too much, so maybe the heat reradiates very quickly and we can only heat up one spot. Then again, we haven’t really tried to heat up the entire skillet; maybe it would work after all. I’d have to try it out to see what happens. I’ve added a pressure cooker to our list of stuff to try lensing.
It looks like a stovetop autoclave is the traditional way to do this, and it would totally work for us: it’s got a temperature gauge and a way to bleed off excess pressure, which I think is all we’d need. However, all the ones I’ve seen are either white or metallic. Are there any black ones? It would absorb more heat because it’s not reflecting as much light.
Re: Steam Generation
Regardless of whether they are white or metallic, a bit of steel wool/sanding and some high temperature black paint will fix the color. Maybe even sanding isn’t needed. The paint should be available at most hardware stores as ‘BBQ paint’ and can be used on super hot surfaces such as…a BBQ. If you can find a way to constantly move (over a slightly larger area) or UNfocus the focal point on the base it will help with too much concentration. If you can find a ceramic element to heat then focused heating won’t be too bad as the ceramic should distribute most of the heat.
The goal is to try to get over 121C, but not by too much, and maintain over 15PSI, again by not more than a few PSI, for 15 minutes. A good pressure cooker has a pressure release valve so over pressurizing shouldn’t be a concern. A cheap timer costs a dollar so timing isn’t a concern. The only issue will be regulating energy input. Too much and it gets too hot, take the source away and the vessel cools. You’re a smart bunch so I know there’s a creative, cheap solution to regulating the input based on temperature.
Perhaps a thermocouple that somehow alters a component property (distance, angle, height, focus…) in order to regulate the temperature?
Crookes radiometer?
I wonder how fast you could get a Crookes radiometer. Probably don’t even need the vacuum bulb.
Re: Crookes radiometer?
Very interesting idea! We probably need the bulb because otherwise we’d have to deal with wind. but I will add this to the list, and look into trying it. Thanks!
distill a little sea water
Try to distill a little sea water. You don’t have to get it down to bottle water quality for lunch but distilling sea water to agricultural levels if you had enough lenses set up in arrays, could have commercial use world wide.
Re: distill a little sea water
In February, I suggested this to the group, and no one else was interested. Thanks for the encouragement; I’ll bring it up again!
Brass.
I have posted the question if this penny really became brass here:
http://www.metalcastingzone.com/metal-casting-forum/brass-casting/is-this-really-brass
Cool project I would really love to do some metal casting with this lense but I don’t think I will drop the $ to do it. Did the zinc inside the penny melt fast? can you melt more then one penny at a time? If you could do enough to make a ring that would be great.
Re: Brass.
We’re pretty sure it is. Do a search for [“brass penny” -whistle] to get other brass penny experiments, though they’re normally chemistry demonstrations (and they often first use a redox reaction to plate some zinc on the outside, so you get results faster). Steve Spangler has a good demonstration, including a video.
It’s surprisingly hard to make a brass penny with the lens. If you heat it up too much, the copper oxidizes and you get a black, nasty penny like the one in the middle row on the right (and it’s really easy to do that!). We spent over a week off and on trying to make a brass penny before we actually succeeded.
The zinc melted within 30 seconds. We’ve gotten stacks of pennies to turn black and charred (see Part 2), but we haven’t gotten them to turn to brass. I don’t recommend using this method to make brass on a regular basis; it’s hard to do right. Just go with the powdered zinc, lye, and blow torch if you’re looking for something reliable.
Re: Brass.
30 seconds is pretty good. It seems like if you can do that you could melt enough zinc for a ring or something else small if you started with pure zinc. Might not be as efficient as using a wood fire or a blowtorch but it would be operating without fuel.
Thanks for the links. That zinc coating experiment is interesting. I guess I don’t really know much or anything of the chemistry of alloys. You must be getting just the very surface hot enough to get some action from the copper.
Its too bad bullet casting thermometers only go up to 1000F otherwise that might be a great thing to try.
Can we ask how much it cost? Unless it’s been said somewhere and I just missed it. And how much would a regular parabolic lens cost?
What about putting a glass prism at the focus?
The lens itself was $120, I think. After buying parts for the frame and stand, skillet, welding goggles, etc., we’ve probably spent $200. You typically can’t buy a regular lens this big.
I doubt the prism will do anything interesting (since the incident light is coming in at a bunch of angles, you won’t diffract spectra in the same directions, and everything will get muddled together), but I’ll mention it to the group.
Oh right, then isn’t there some kind of converging lens you can get? Still not sure how exciting that’d be, but it might make for some neat play with a straight heat ray.
projecting onto a cloudy sky
When I was a teenager I used to mount large Fresnel lenses into sliding boxes and project real-time mode-x graphics onto cloudy skies at night. The results would vary, and I could never get my hands on a really big lens, but I’m sure it would be and interesting (and less destructive) experiment.
Imagine a Batman-like Google Sign! Creepy.
Re: projecting onto a cloudy sky
Interesting idea! I’ll mention it to the group, and see what happens. There aren’t many people at the office at night, though, so I’m not sure we’ll actually get around to trying this out.
In honor of Easter, how about lensing a PEEP?
Big Lens
You could use it to fry some really, really big ants.
But seriously: I believe you could construct a practical cooker using steam. Make a steel boiler for generating the steam; if the steam is kept at low pressure, you can use a simple valve arrangement and reservoir to keep the boiler topped up, even automatically.
The steam is then piped to various cooking devices; using steam as a heat source, you can steam, boil, grill, and even fry (though the latter only slowly).
Re: Big Lens
Invite Jay Leno to work with you. He seems to be one of the world’s leading experts on steam engines for vehicles (no joke). Maybe you could start with a little model.
Use 2 lens to get uniform heating…
You can use a combination of 2 lenses to get uniform parallel rays, having more energy (i.e. light rays) per unit area.
The second lens that is to be introduced in this case, should have following properties
1. small in size relative to the first lens. (So that it generates parallel rays in less area)
2. small focal length so that it can be kept close to the focal point of the first lens.
It’s is a theoretical concept that came to my mind while reading your blog,. Let me know if it works to sort out your problem of too soon too hot problem.
Re: Use 2 lens to get uniform heating…
I think you’re suggesting a death ray set-up, where you use a second lens to straighten all the rays of light out so that they’re parallel again but concentrated over a smaller area. We considered that at the end of part 1 and decided against it because it would be too dangerous. When you have a beam that extends indefinitely far out, you’re likely to accidentally get something caught in it that you really don’t want there, and start a fire (or ruin your hammock, or something).
It’s a very cool idea, and if we had a large open area to do this far away from any buildings, we’d probably give it a shot. but with our current surroundings, we’re not going to risk it. Good suggestion, though!