Have you ever started a fire with a magnifying glass in science class or girl/boy scouts? Well, in my search for a zero energy means of cooking, I came across fresnel lenses. These are strong magnifying lenses that have a variety of uses including reading magnification, flat screen televisions, RVs and motor vehicles to help with blind spots, as well as to start fires. Yes you read that correctly.
Some of you are probably familiar with fresnel lenses as they are used by science enthusiasts, outdoorsmen, survivalists, and homesteaders for the purpose of fire starting and cooking. They make lighting a piece of wood almost effortless once the right angle to the sun and focal length is found. Depending on the strength of the lens and what type it is, temperatures in excess of 2000 degrees Fahrenheit can be reached, melting a nickel penny, within a matter of seconds.
There are two types of fresnel lenses. They are known as either spot or linear lenses. They magnify differently so that the spot lens condenses the sun into a very intense circular spot about a half an inch at its strongest. The linear lenses condense the sun into a weaker thin beam of light which is due to the way it spreads out the light. Both can get hot enough to cook with. The linear lenses are said to be best for cooking because they disburse the sun more evenly over a larger area. That makes the temperature lower, but still very hot.
To be sure, these can also be quite dangerous. I weighed the risks and rewards, deciding it would be a good investment for our homestead. I chose to get a smaller spot lens that has been measured to reach approximately 1000 degrees at full strength. In the future I'll be designing an outdoor cooking area using a combination of offgrid cooking tools. This is the first element which I will be able to use immediately.
Proper safety is important. I will be using welding goggles and bbq mitts that can withstand heat of up to 1400 degrees, as well as trying to construct a sturdy flexible stand and safety backdrop of cob (I think. Still thinking on it). It's also important to have a laser thermometer and use cooking utensils that will not explode, melt, catch fire, or warp. That's why it's smart to have the heat gun thermometer to accurately measure temperatures. I plan to use stainless steel, cast iron, and cob.
Some people go hunting for free discarded flat screen tvs in order to disassemble them for the fresnel lenses they contain. I chose to buy from a company called Green Power Science. I've watched a lot of their YouTube video demonstrations, which you can view on their channel here. If you want to learn more about what fresnel lenses are, how they work, etc, be sure to check out their website. Here is a video about cooking eggs with the fresnel lens. Can't wait to get cooking myself!
I also purchased 6 linear feet of highly reflective mirrored aluminum with a sticky back so that in the future I can try my hand at building a solar oven. I purchased these items Monday and received them yesterday. Fast shipping and everything looks good to me except for a spot on the lens where it looks like a dribble of glue from the frame trickled down. This shouldn't affect the function of the lens. Excited to give the lens a try soon. Hopefully it won't take me months to work on building a solar oven, but I know I have a really good reflective material on hand whenever the project gets started. This post will be showing you what I got in a STEEMIT EXCLUSIVE UNBOXING. { :
The lens I chose is a 15" square spot lens in a nicely made frame. On each side of the frame is a small predrilled hole to attach it to a stand with butterfly screws so it can be angled perpendicular to the sun. I don't have a stand made yet. I will probably also want to paint or stain the frame to help it last longer.
I got this size of a spot lens because I don't need the temperature to reach 2000 degrees in a few seconds. On the listing this was the data:
SIZE-----------------15H X 15W
BEAM-----------------SPOT
BEAM SIZE MAX POWER--0.3 INCH
FOCAL LENGTH---------18 INCHES
WEIGHT --------------2 LBS.
MAX TEMP. CLIMB------970 F IR THERMOMETER
MAX COLLECTION-------1099F MATERIAL EST...........
MATERIALS TESTED:
WATER-------5oz. BOILS 50 sec.
GLASS-------MELTS 1/8 OUNCE
ZINC PENNY--15 SECONDSΩ
I will also be able to control the temperature by adjusting the distance from the lens to whatever I'm going to cook. That distance is what is known as the focal length. The hottest, most efficient, focal length for this one is supposed to be 18". If I want a lower temperature and larger coverage area, I should be able to pull this away by a few inches. I'll know more once I experiment.
The lens was well packed with a thick layer of cardboard on each side and within a snug box cut to the specific dimensions of it. The lens itself was covered in several layers of saran wrap.
Of the top edge were two very helpful labels. One with the warning that this is not a toy and it can be very dangerous if left where sun can hit it. The other explaining which side faces the sun.
This is the highly reflective material I will be using for the reflective backing for the sun oven. It can also be used to make a parabolic mirror. As you can see it's got some stuff on the left side but that's actually just dust particles. At first I thought it was scuffed but it wiped away. Now I have to either find a solar oven design I want to try making, or come up with my own design. I like designing so I am leaning on going in that direction.
To make the experience extra special, they even drew a sunny smiley face and gave a little extra of the reflective material. The dimensions that can be ordered are 1'x2'. I bought 3 of those, so should have about 6 linear feet.
Hope you enjoyed this unboxing. Be sure to check out Green Power Science for more information. If you are interested in purchasing from them, check their ebay store. If you found this post enjoyable, please consider upvoting, resteeming, following, and commenting! Thank you kindly for reading...
ALL IMAGES ARE COPYRIGHT 2018 BY ME, @phedizzle. Hope you enjoyed them!
Here are previous posts of mine:
STORIES:
BAREFOOT IN THE BOONIES: EXPOSING MY ROOTS (introduction post)
BAREFOOT IN THE BOONIES: Chapter 1
BAREFOOT IN THE BOONIES: FAMILY OWNED: Chapter 1 Section 2
BAREFOOT IN THE BOONIES: ABANDONED BASEMENT: Chapter 1 Section 2
BAREFOOT IN THE BOONIES: REWIND: GROWING UP WITH TURNTABLES
2011 GARDEN:
2011: DESIGN AND BUILD
2011 BACKYARD TRELLIS, PERIMETER, & VOLUNTEER
2011 TIRE PORTION OF THE GARDEN
2011 BRASSICAS-TIRE GARDEN
2011 DWARF ORCHARD
RECIPES:
SANTA DELIVERED SHROOMS-SHITAKE OYSTER SCRAMBLE
SWEET CINNAMON POPCORN
MOCK ALMOND JOY--CHEAPER AND HEALTHIER
HANGRY TERIYAKI
RASHES--WHY I SWITCHED TO THIS COMMON DIY LAUNDRY SOAP AND HOW I MAKE IT
SCRAMBLED EGGS WITH FORAGED FINDS: FIRST FOOD FORAGE OF 2018
WHAT'S FOR DINNER? BEETS ME! FIRST GARDEN HARVEST AND RECIPE
POEMS:
WATCHING THE SPRING WAKE UP
SHE IS DYING
WEEPING WILLOW
LIGHTS OUT BABY ROBIN
PLANTS AND ANIMALS-EDUCATIONAL:
GRASS IS OUR FRIEND
LITTLE BLUESTEM--BENEFICIAL AND BEAUTIFUL
BEHOLD THE BEAUTY OF THE FALSE INDIGO BUSH
WALK ALONG WITH ME:
WALK ALONG WITH ME 1
WALK ALONG WITH ME 2--WINTER 2017/2018
2018:
WILD TURKEY TAIL AND REISHI MUSHROOMS
HUGELKULTUR BED STARTED BUT THERE IS A LOGISTICAL OBSTACLE.
2018 CURRENT HAPPENINGS: FOOD FOREST EXPANSION
WILD EDIBLES AROUND THE HOMESTEAD
GRANNY SMITH APPLE FINALLY GOT SOME LOVE
PICKED MY FIRST PINT OF WILD NATIVE BLACK RASPBERRIES
TRANSPLANTING WILD PURPLE GARLIC PART 1
ORCHARD: PLANNING, PREPPING, AND PLANTING
WILD PURPLE GARLIC TRANSPLANT UPDATE
ZONE 2 OF THE FOOD FOREST
COMFREY: ANOTHER QUINTESSENTIAL PERMACULTURE ADDITION TO OUR FOOD FOREST
ONE OUT OF MANY: MY FIRST TIME GROWING SWEET POTATOES
CONTESTS/REVIEWS
Chronic and Coffee MSP Review--25 SBD contest for the best MSPWAVES Radio Reviews
VOICES FROM THE MOUNTAINS Review--25 SBD contest for the best MSPWAVES Radio Reviews
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Well, that should be fun! You could destroy a fire ant nest in short order with one of those lenses. :-)
HAHA. I could but if I were going to kill anything with this it would either be brown recluses or Japanese beetles. Unfortunately, I'd probably light up the whole county if I did that. lol
My plan is to use the cast iron griddle first. Bet I could make a yummy pizza or steaks. mmm.
Yeah, killing the spiders might end up involving a house fire...
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awesome post :D got my 2 cents, and my interest ( which is hard to keep) XD
Nice! I made a sun cooking thingy in science class so I know it'll work. I made nachos but I could've made a baked potato with that California heat. Lol! And mine wasn't made with a magnifying glass. Cardboard structure, black construction paper on the outside, foil on the inside. Seran wrap for the window. I can't wait to see what you make with this! I can imagine a really tasty pizza😋 nomnomnom
cool article, I used to have an 8 by 12 one, have fun and be careful, I wonder if your best bet would be to use it with some cast iron cookware like a Dutch oven
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As awesome as this think I've never heard of before is... the first thought that comes to my mind when looking at it is... "dat glass"
Hmm, interesting... I've never heard of such a thing, I would like to see it in action. just curious how it works...
So this is what you were talking about,, you finally got it..
I can't wait to see some finished deliciously cooked PheFood :)
Great post as always....I always love your descriptions and through explanations :)
Is this the same of a solar kitchen? I've heard a lot about them, but I've never seen one of them operational.
Anyway this was very interesting, thank you for sharing :)