[EMS Discuss] Solar Foundry

Rick Osgood rick at eugenemakerspace.com
Sat Jan 25 14:17:32 PST 2014


I want to see this lens cook breakfast some day.


On Sat, Jan 25, 2014 at 10:21 AM, Bob Miller <kbob at jogger-egg.com> wrote:

> "pass light through in both directions", not dimensions.  Sorry.
>
>
> On Sat, Jan 25, 2014 at 10:20 AM, Bob Miller <kbob at jogger-egg.com> wrote:
>
>> A 52" irregular plastic box?  We can hold a puppet show!
>>
>> If the frosting is on the opposite side from the Fresnel grating, you
>> might be able to buff out the frosting with Novus #2 polish.  I have a
>> bottle if you want to try.  If you know what kind of plastic it is, you can
>> also clean it and wet it with [solvent] to melt and re-flow the surface.
>>  The second approach is easier but more likely to destroy the lens if it
>> doesn't work.
>>
>> Also, be sure to try passing light through in both dimensions.  The
>> interaction of the grating with the frosting may work differently in one
>> direction than the other.
>>
>>
>> On Sat, Jan 25, 2014 at 9:47 AM, Mark Danburg-Wyld <danburgwyld at gmail.com
>> > wrote:
>>
>>> Update on this...
>>>
>>> Bob got me the 11" square lenses a few weeks ago. I have one of them
>>> mounted in a wooden frame, and it does produce enough heat that I was able,
>>> for instance, to set a piece of cardboard on fire using it.
>>>
>>> I also acquired a dead rear projection flat screen tv last night, which
>>> I pulled a 46" x 26" lens from. The bigger lens has a "frosted" appearance
>>> to it, versus the clear smaller lens. I'm not sure if that will limit its
>>> potential but it seems sub-optimal. The salvaged framing from the tv is not
>>> quite rigid enough to keep the lens from bending when you're flipping it
>>> all around by yourself, but it also definitely seems to put a lot of heat
>>> into a very small space. I haven't managed to set anything on fire with it
>>> - yet.
>>>
>>> My next planned step is to acquire some lumber to make it a bit more
>>> rigid, maybe build a stand for it. After a bit more... research... it'll
>>> come to live in the shop. I'm also salvaging other bits from the tv (nice
>>> speakers! ooh - hdmi inputs...), the useful bits will find their way into
>>> the supply area, but I plan to scrap the body - anyone with a pressing need
>>> for a 52" irregular plastic box let me know.
>>>
>>> Thanks,
>>>
>>>
>>> On Tue, Sep 10, 2013 at 10:20 AM, Bob Miller <kbob at jogger-egg.com>wrote:
>>>
>>>> You spoke first.  You've got a lens.  Please set things on fire where
>>>> we can watch. (-:
>>>>
>>>> I am totally intrigued by John's harmonograph idea, though.  It seems
>>>> like a challenging mechanical design problem.  So the other lens is
>>>> reserved for harmonographics.
>>>>
>>>> The focal length on these lenses appears to be 6 to 8 feet.
>>>>
>>>> On Tue, Sep 10, 2013 at 8:51 AM, Mark Danburg-Wyld
>>>> <danburgwyld at gmail.com> wrote:
>>>> > Keeping the focal point on a plane would be a problem for a
>>>> harmonograph,
>>>> > probably.
>>>> >
>>>> > Bob, I would appreciate a lens. I promise to set something on fire
>>>> with it,
>>>> > but in a controlled, contained manner.
>>>> >
>>>> >
>>>> > On Tue, Sep 10, 2013 at 5:46 AM, John Burridge <
>>>> burridge.john at gmail.com>
>>>> > wrote:
>>>> >>
>>>> >> Hmmm.  Sand tray + fresnel lens + two pipes on universal joints =
>>>> >> solar harmonograph.
>>>> >>
>>>> >> On Tue, Sep 10, 2013 at 2:25 AM, Bob Miller <kbob at jogger-egg.com>
>>>> wrote:
>>>> >> > Solar food cookers generally work in cloudy conditions.  They are
>>>> not
>>>> >> > as hot, obviously.  If I recall, they take about twice as long to
>>>> cook
>>>> >> > on a cloudy day.
>>>> >> >
>>>> >> > The foundry has a very small working volume so it requires a
>>>> >> > concentrated light source.
>>>> >> >
>>>> >> > In other news, I found my fresnel lens.  I actually have two of
>>>> them,
>>>> >> > but they are small.  11 inches square.  They are still available to
>>>> >> > anyone who is actually going to build one of these.
>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> > On Sun, Sep 8, 2013 at 8:01 PM, Weston Turner <
>>>> wstnturner at gmail.com>
>>>> >> > wrote:
>>>> >> >> Do you think that even in the winter months it might produce
>>>> enough
>>>> >> >> heat to
>>>> >> >> use it as a solar oven? If you could cook with it even in overcast
>>>> >> >> whether,
>>>> >> >> it would be a cool demonstration of how much solar energy makes it
>>>> >> >> through
>>>> >> >> the clouds even in the rainy season.
>>>> >> >>
>>>> >> >> Just a thought as to what it might be useful for the other 8-9
>>>> months
>>>> >> >> of the
>>>> >> >> year.
>>>> >> >>
>>>> >> >> Weston
>>>> >> >>
>>>> >> >> On Sep 8, 2013, at 7:51 PM, Sam Foster <sam at sneetchworks.com>
>>>> wrote:
>>>> >> >>
>>>> >> >> Oh I've seen this video. We need a large fresnel lens - they come
>>>> from
>>>> >> >> large
>>>> >> >> old rear projection tvs. In other words with some judicious
>>>> scavenging,
>>>> >> >> the
>>>> >> >> whole build shouldn't cost more than a bit of lumber and fixings.
>>>> >> >>
>>>> >> >> On 9/8/2013 7:27 PM, Mark Danburg-Wyld wrote:
>>>> >> >>
>>>> >> >> Step 1: Watch this video:
>>>> http://www.youtube.com/watch?v=drE54ctrHBY
>>>> >> >> Step B: Let me know if you'd be interested in building a solar
>>>> foundry
>>>> >> >> for
>>>> >> >> EMS
>>>> >> >> ???
>>>> >> >> Step 4: Profit!
>>>> >> >>
>>>> >> >>
>>>> >> >> _______________________________________________
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>>>> >> >>
>>>> >> >>
>>>> http://eugenemakerspace.com/mailman/listinfo/com.eugenemakerspace.discuss
>>>> >> >>
>>>> >> >>
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>>>> >> >>
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>>>> >> >
>>>> >> >
>>>> >> >
>>>> >> > --
>>>> >> > Bob Miller                              K<bob>
>>>> >> >                                         kbob at jogger-egg.com
>>>> >> > _______________________________________________
>>>> >> > Discuss mailing list
>>>> >> > Discuss at eugenemakerspace.com
>>>> >> >
>>>> >> >
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>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> ----
>>>> >>
>>>> >> John Burridge
>>>> >> burridge.john at gmail.com
>>>> >> http://johnburridge.blogspot.com
>>>> >> _______________________________________________
>>>> >> Discuss mailing list
>>>> >> Discuss at eugenemakerspace.com
>>>> >>
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>>>> >
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> Bob Miller                              K<bob>
>>>>                                         kbob at jogger-egg.com
>>>>
>>>
>>>
>>
>>
>> --
>> Bob Miller                              K<bob>
>>                                         kbob at jogger-egg.com
>>
>
>
>
> --
> Bob Miller                              K<bob>
>                                         kbob at jogger-egg.com
>
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