Parabalic Dish Coating

[cvo]

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

[hvirtane]

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

[hvirtane]

Ah,

forgot to mention the stuff,

which is maybe the best.

Please check the material

as sold by:

http://www.cleardomesolar.com

- Hannu

[cevonk]

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.

[Leen]

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

[Vtbsr]

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.

[veewee77]

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

[cvo]

Thanks for the links and input. Curtis

[dconn]

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

Derek

[nothing to lose]

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!

[tecker]

 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 )

[tecker]

 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

[cevonk]

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.

[tecker]

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 .

[wooferhound]

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

[juiced]

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.