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Parabalic Dish Coating
By cvo, Section Solar Posted on Wed Sep 29, 2004 at 07:32:48 AM MST
What's a good material to line my parabolic dish?

I've an old satllite dish, 8ft+, that I'm experimenting with that I need to line with a reflective material.
So far, I've come up with a few choices: mylar, alluminum foil, paint and scrap glass pieces.
Anyone know of something else?
I like the alluminum foil cause it seems so cheap and easy and may serve for now my experimenting stages.
Alluminum paint is next....cheap and easy.
My goal is to heat water through the use of a radiator placed at the focal point, and then cylce the hot water into holding tank(s).
I'd like to harness this high temp possiblities. As a former pipefitter/ironworker I know what steam/hot water are capable of.
Any input would be appreciated.
Thanks,
Curtis

Parabalic Dish Coating | 15 comments (15 topical)

Re: Parabalic Dish Coating (3.00 / 0) (#1)
by hvirtane on Wed Sep 29, 2004 at 11:30:23 AM MST

I think that you already listed almost
all the possibilities.

I would try also small mirror pieces.

I made a reflector of a satellite
dish using chromium plated plastic
meant for covering books. I've no
idea, if that stuff is available,
where you are. Mine was a German product.

You might find as well some chromium tape
made for car bumpers.

'WindstuffEd' might
know well about other kinds of chromium
plating systems for cars?

There used to be
methods for home made chromium plating,
but the stuff is poisonous; you can ask
shops selling parts for car restoration.

- Hannu

Re: Parabalic Dish Coating (3.00 / 0) (#2)
by hvirtane on Wed Sep 29, 2004 at 11:36:33 AM MST

Ah,

forgot to mention the stuff,
which is maybe the best.
Please check the material
as sold by:

http://www.cleardomesolar.com

- Hannu

Re: Parabalic Dish Coating (3.00 / 0) (#3)
by cevonk on Wed Sep 29, 2004 at 11:57:54 AM MST

http://www.fsec.ucf.edu/Solar/PROJECTS/SolarCooker/reflectivematerialsreport.pdf

A link to a comparative discussion of some commercially available materials that you might use, including comparison of the effects on the materials of long term solar exposure.

Re: Parabalic Dish Coating (3.00 / 0) (#4)
by Leen on Wed Sep 29, 2004 at 12:02:01 PM MST

Perhaps an idea to use insulationmaterial.
Here in the netherlans there are several materials on a roll.
It's a kind of thin foam on a layer of aluminum.
I have seen it in golden color aswell as silver.

succes Leen

[ Parent ]

Re: Parabalic Dish Coating (3.00 / 0) (#5)
by Vtbsr on Wed Sep 29, 2004 at 05:52:24 PM MST

Do you have any ideas on how to track the sun with this? It seems like you would have to follow very close or you won't get the sun at the focal point.

Re: Parabalic Dish Coating (3.00 / 0) (#6)
by veewee77 on Wed Sep 29, 2004 at 09:57:14 PM MST

Tracking is tricky but doable.
I have a solid aluminum dish that I made a solar cooker out of and it works VERY GOOD!!!!

I just polished the aluminum to a shine (not as good as possible but pretty good, anyway. . .

You can hold a piece of wood in the FP and it will start smoking immediately.

A radiator wouldn't be the best for the FP collector. Use a coil of steel line coiled flat, painted with high temp black paint. Use 1/4 -3/8 I would think. I have not tried this yet but will soon and see what happens.

Doug

Re: Parabalic Dish Coating (3.00 / 0) (#7)
by cvo on Thu Sep 30, 2004 at 02:56:53 AM MST

Thanks for the links and input. Curtis

Re: Parabalic Dish Coating (3.00 / 0) (#8)
by dconn on Thu Sep 30, 2004 at 05:32:02 AM MST

Hi Curtis, I purchased some Mylar type shiny stuff from www.mirrorsheeting.com - for just the same purpose as you.

Derek

Re: Parabalic Dish Coating (3.00 / 0) (#9)
by nothing to lose on Thu Sep 30, 2004 at 08:36:21 AM MST

Mention of chrome plating.
If it's a metal dish you could chrome plate it very easy. Check out caswell.com for brush plating kits. Small and fairly cheap, but still expensive depending how you look at it. Very easy to do. I have several different setups for chrome plating. gold plating, ect... It's all the same thing no matter how you do it for triple plate show chrome (which you don't need that quality anyway). First polish to the finish you want (mirror for show quality) plate with copper, buff/polish (for show) plate with nickle, plate with chrome. Chrome is actually a Blueish clear hardcoat over the nickle to keep the softer nickle from being damaged easly and to also prevent the nickle from tarnishing plus other reasons. Basically when you look at the mirror chrome finsih on a show car, it's the nickle your seeing and the blueish tint is the chrome. Most people do not know that! Many people think triple plated show chrome was chrome plated 3 times :)

Anyway if your looking for a good durable reflective mirror finish on metal and want to invest a little time and some (not alot) of money then look into plating it. Those brush kits do work well, they just take longer to use than dipping but also take much less material than a tank would. They also have other things you can use too for the same basic results though I haven't use it.

Buy a kit and you'll be plating everything in the house for awhile! I have nickle pennies, copper nickles, 24k gold plated dimes :)

Boy does my bank look at me funny sometimes! :)
.
nothing to lose

Spelin and tpying are my strong points, not electronics.

Re: Parabalic Dish Coating (3.00 / 0) (#10)
by tecker on Fri Oct 01, 2004 at 08:46:04 AM MST

I'm trying to take mirror pieces and bond them to a direct tv dish as a test they fit close enough together to give a very good surface and it's easy to clean milar worked good but it goes cloudy fast .So far a 1"by 1" works . The arc on this dish is very wide .If the proformace is good I'll try a direcpc dish I also have primstar
dish but I want to use it to make a plaster form first . A good target can be made by with aluminum cans the cans melt fast in an iron skillet over a fire
and useing a Mapp tourch to get the cans up to temp . You can then pour the metal over the target you want to use (copper coil or somthing larger for air I use 1" copper pipe for air heating )

Re: Parabalic Dish Coating (3.00 / 0) (#11)
by tecker on Fri Oct 01, 2004 at 08:55:17 AM MST

The interesting point about the mirror pieces is each segment has is own beam that
is highly reflective with a wide band of light very hot .take care when assembling if you choose this method

[ Parent ]

Re: Parabalic Dish Coating (3.00 / 0) (#12)
by cevonk on Fri Oct 01, 2004 at 12:44:13 PM MST

Have you seen this design?

http://www.ida.net/users/tetonsl/solar/page_iii.htm

6KW using 1'x1' mirror tiles. Very similar in principal to what you are doing. I would like to do something like this one day using either PVD aluminized steel, aluminum, or perhaps titanium. The reflectivity of the metals is lower than the reflectivity of mirrors, although some of the aluminum is close, and that introduces a greater degree of inefficiency into the system at the very start. The benefit of this sacrifice in efficiency, I think, would be that the metal mirrors would have a much greater life and be much easier to handle over time.

[ Parent ]

Re: Parabalic Dish Coating (3.00 / 0) (#13)
by tecker on Fri Oct 01, 2004 at 02:58:22 PM MST

yes I'm upbeat about this technique because silvering has a good bandwidth and the small sections provide a good sevicability with respect to damage reflector ,cleaning and simple wear and tear .

[ Parent ]

Re: Parabalic Dish Coating (3.00 / 0) (#14)
by wooferhound on Sat Oct 02, 2004 at 09:56:09 AM MST

purchase mirror squares, 1/2, 3/4 and 1 inch squares
http://www.artfulcrafter.com/MirrorTiles.html

Mirror squares connected together with a cotton backing: 1/2 and 1 inch
http://www.nationalproducts.com/disco.htm

Interesting story about Boiling water using foot square mirrors
http://www.cockeyed.com/incredible/parabola/parabola.html

)}=- W o o f -={(

Re: Parabalic Dish Coating (3.00 / 0) (#15)
by juiced on Sat Oct 09, 2004 at 09:29:12 AM MST

What about reflective tape from 3M? They have some products for fire-fighting applications that are VERY reflective. Heat resistant as well. Its like little hexagons reflecting off each other.

Canada's -Debatable- A.E./R.E Debate Site
News, discussions and debates!
www.juiced.ca

Parabalic Dish Coating | 15 comments (15 topical)

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