[EMS Discuss] Solar Foundry

Bob Miller kbob at jogger-egg.com
Sat Jan 25 10:21:13 PST 2014


"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!
>>> >> >>
>>> >> >>
>>> >> >> _______________________________________________
>>> >> >> Discuss mailing list
>>> >> >> Discuss at eugenemakerspace.com
>>> >> >>
>>> >> >>
>>> http://eugenemakerspace.com/mailman/listinfo/com.eugenemakerspace.discuss
>>> >> >>
>>> >> >>
>>> >> >> _______________________________________________
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>>> >> >>
>>> >> >>
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>>> >> >>
>>> >> >>
>>> >> >> _______________________________________________
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>>> >> >> Discuss at eugenemakerspace.com
>>> >> >>
>>> >> >>
>>> http://eugenemakerspace.com/mailman/listinfo/com.eugenemakerspace.discuss
>>> >> >>
>>> >> >
>>> >> >
>>> >> >
>>> >> > --
>>> >> > Bob Miller                              K<bob>
>>> >> >                                         kbob at jogger-egg.com
>>> >> > _______________________________________________
>>> >> > Discuss mailing list
>>> >> > Discuss at eugenemakerspace.com
>>> >> >
>>> >> >
>>> http://eugenemakerspace.com/mailman/listinfo/com.eugenemakerspace.discuss
>>> >>
>>> >>
>>> >>
>>> >> --
>>> >> ----
>>> >>
>>> >> John Burridge
>>> >> burridge.john at gmail.com
>>> >> http://johnburridge.blogspot.com
>>> >> _______________________________________________
>>> >> Discuss mailing list
>>> >> Discuss at eugenemakerspace.com
>>> >>
>>> http://eugenemakerspace.com/mailman/listinfo/com.eugenemakerspace.discuss
>>> >
>>> >
>>>
>>>
>>>
>>> --
>>> 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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