Discussion in 'Functional Gear & Equipment' started by hidden211, Apr 19, 2013.
or for purifying water.....
Hummm... time to start saving all of those champagne bottles....
My wife is going to hate you, hidden211, because now I'm adding rear projection big screen TVs to my curbside junk pickup list. I already stop for CRT TVs so I can strip them for electronic components. Drives my wife nuts...
we must be married to the same woman lol
It did not occur to me, there was a Fresnel lens in there. I have been offered several over the last couple of years. (the last one was nearly 4X6 screen size.) i will have to keep my eyes open for one. (or 6)
I never knew either kellory makes for an interesting project though
Found a smaller version fresnel lens that you can carry in your wallet to use as a fire starter-$3.00 at Fire - Fresnel Lens - Bens Outdoor Products
Found one out at the street and stripped the Fresnel Lens out of it. took a lever to pop the front off the chassis, wire cutters for the small wires at the bottom of the housing, and a #2 Phillips in a drill and I had it out in about two minutes. Think I will surround it with 1 inch PVC, slotted to fit around it like a picture frame.
let me know how it turns out still looking for one.i did order a 5 pack of the fire starter lenses
I saw this on Dooms Day Prepper a year or two ago. I now have two but found out there or 5 or 6 screens that end up with a different focus so some of the beams are wider than others. They do cook food and boil water fine, but one with a tight focal point heated up a piece of steel to where he was working the steel. I wish I could remember what TV he used. Anyway, if the wife gets upset it is Bushs fault not yours.
Be Prepared - Be Prayerful - Be Thankful - You are an American
I have a question regarding fresnel lens. I took one out of a TV. It is big and awkward. I was wondering if I cut it into smaller pieces would it still be effective or does it need to remain large? I would like to chop my lens into 12'x12" so it could fit into packs and easy to store. I have not read anywhere that someone has cut a lens, only used them whole.
Effective, yes, but reduced a bit in heating rate. The amount of ol' Sol's power is directly related to the capture area.
If your purpose is to cook from the use of a lens, I would rather use a method to start a fire and cook that way. I carry one of these in every kit I have, even one for my wallet: Amazon.com: 3x Wallet Magnifier • Credit Card Size Fresnel Lenses by Cz Garden Supply: Office Products
Cutting up you lens will not work .
If you look closely at the surface it is a series of circles like a record all working together to make the focused beam of light.
Also not all fresnel lenses will work for this . not all are made to focus into a beam . You may go through several TVs to find one .
Could a holding tank of water be heated consistently with such lens?
Negative. The lens I linked is for concentrating a small point of sunlight for starting a fire. With the fire you can do many things, though.
@Brokor- I think the question was intended more generally than that. As asked, there are too many unknown factors to give a good answer. So, maybe.
If you cut to save the center, it'll work, just as stated above in post 13. You are right, a random hunk of busted fresnel will do nothing useful but cut. The center is the important part, and then only if it is big enough.
Ah, okay. Well, if one were using a fresnel lens to heat water in volume, it would be ideal to use a focus chamber of sorts and find a method to pump the water through it in a timed fashion which would allow each quantity of water inside the chamber to be heated according to the requirements. (As opposed to trying to heat a large container all at once due to latent heat problems)
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