Can and LED floodlight possibly be as bright as a real floodlight?

Have you never boiled water in a styrofoam cup over an open flame?

One can. The water keeps the temperature of the foam below its melting point.

I thought I remembered seeing a Sears plastic electric HWH many years ago. Do they still make them, or did they last too long?

Think porcelin like a sink or bath tub. It's firmly bonded to the metal.

Yes. It requires a heat spreader between the cup and the flame. Apply the flame directly and the hot spot will burn a hole in the styrofoam.

True. However, a gas water heater has to deal with stratification, where the water is much hotter near the flame than near the tank outlet. I couldn't determine how much of a temperature difference by Googling. You're probably correct that it won't melt if it's decent plastic, but I'm still suspicious. Unless secured to the steel tank, it might soften, warp, bend, buckle, or otherwise provide an excuse for water to get to the steel. From there, it's only the anode rod that protects the steel tank from corrosion.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Well, let's do the math. Coefficient of linear expansion for: steel = 12*10^-6 m/m-K alumina = 5.4*10^-6 m/m-K

From 25C to 100C (near the burner) on a 2 meter high tank, the steel will expand: 12*10^-6 m/m-K * 2m * (100-25) = 1.8 mm and the ceramic: 5.4*10^-6 m/m-K * 2m * (100-25) = 0.8 mm

1mm difference doesn't sound like much, but if both materials are rigid, it could easily delaminate. The alumina ceramic is very rigid, but the steel can bend. If the tank were allowed to bulge slightly in the middle, it would work, if the alumina can survive being under constant tension without cracking.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Yes, I've seen LED flood lights that were plenty bright.

--
. 
Christopher A. Young 
Learn about Jesus 
     www.lds.org 
.

No time tonight to watch this. Tomorrow.

BTW, I learned that you can saw though the outermost rather thin steel layer of a water heater (the part that you see) with a reciprocating saw, even if the blade no longer has any teeth. They all wore away but it still cut fairly well. Certainly it wasn't worth changing the blade.

I woudn't call it soft. It bent, but it wasn't flimsy. Maybe the stiffness was a little greater than a bicycle tire.

My water heaters are electric too.

Tomorrow I'll look to see if they have electric.

I wanted to check if my water heater was advertised as glass-lines, so I started looking on the web. Then it dawned on me that a better way would be to look on the water heater, which probably still has labels on it. (Yes, it has several.)

And the top label includes "Cobalt Blue Ultra-Coat (or Cote) Glass Lining." but I'll bet you any money that this Kenmore water heater is built just the same as the last one, with the 1/4" (or slightly less, not more like I said.) layer of clear/milky vinyl?, something like plastic milk cartons would be if they were thicker, probably with glass mixed in, because otherwise t hey couldn't say "glass lining". Or maybe it's largely crushed glass in some "plastic" medium.

I think Kenmore is AOSmith because the intake and output pipes are exactly the same distance apart as the wh that came with the house (when no other brand I looked at had that. I'm compulsive. I didn't want to use flexible and I didn't want zig-zag piping. ) And the front panels were the same (although maybe they all use the same thermostats and heaters.) Basically everything looks the same as the original.

Charlie+ wrote in news: snipped-for-privacy@4ax.com:

Over in the UK they tend to be copper or stainless and maintenance free lifespans of 40+ years are not unusual. e.g. Albion brand stainless hot water cylinders dont use any anodes and have a 25 year anti-corrosion warrenty on the tank. The immersion heater element circuit should be RCD protected, both for safety and so that any insulation failure will be detected before significant electrolytic corrosion can occur.

Whoever first introduced vitreous enamel-lined mild steel hot water tanks to the American market did you all a great disservice.

--
Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)  
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk  
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL

ALso plastic doesn't conduct heat all that well, leading to an inefficient WH. Also a gas HWH has a pretty powerful burner, mine's rated at 40,000 BTU/hour input. I suspect you suspicions about the plastic buckling/warping and separating from the steel tank are correct.

No, no. You don't want any thermal conduction through the plastic liner. The whole idea is to keep the heat inside the tank, not radiate or conduct it to the outside. That's why there's a mess of fiberglass insulation between the steel water tank and the outside cosmetic steel cover. Some people add an additional water heater insulating "jacket" on the outside of the heater. A thermal insulating plastic layer between the water and the steel tank should improve efficiency.

An easy way to tell if your water heater is a piece of junk is to measure the case temperature of the water heater. Use a contact thermometer (Thermocouple or thermistor, not optical IR). It's probably the worst at the top of the heater. If the outer case is warmer than the ambient air, you're wasting energy heating that atmosphere instead of the water. Same with a refrigerator. If the case of the fridge is colder than ambient, you're cooling the kitchen.

That was just a guess. I'm not so sure any more. The plastic liner and steel tank are both fairly flexible, so they can bend and bulge without breaking anything. You'll never see it because it all happens inside the tank. If they're glued together (bonded) properly, I don't think they will come apart. I was wondering why the water tank didn't have stiffening ribs, which would allow the use of thinner steel. I guess(tm) stiffening might interfere with the necessary flexing of the tank with temperature.

It should also be possible to dope the alumina ceramic coating with something to help it match the coefficient of thermal expansion for the steel. Even so, stratification, and the difference between temperatures on both sides of the steel tank, will create enough of a temperature gradient to possibly microcrack the ceramic.

Incidentally, it doesn't take much movement to wreck a ceramic coating. I had a nice ceramic coated steel tea kettle that I usually heat on the kitchen stove top to about 180C. One day, I stupidly put it directly on top of my wood burner running at about 300C. I compounded the error by boiling off all the water. My first indication of a problem was the sound of something like popcorn from inside the kettle. That was the inside coating flaking off and bouncing around. As I approached, a large piece of the outside coating flew off in my general direction. I had to use a broomstick to remove the kettle. I haven't calculated the differences in expansion, but for something as small as a kettle, it was much smaller than my predicted 1mm.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Subject line change, no charge.

The ones we have at church are just fine. I don't know the make and model. But, yes, they can.

--
. 
Christopher A. Young 
Learn about Jesus 
     www.lds.org 
.

The Sears model number will tell you who made it.

--
Anyone wanting to run for any political office in the US should have to 
have a DD214, and a honorable discharge.

There are numerous Sears manufacturers lists available online. Many have missing prefix numbers or only include specific classifications, such as power tools. If you can't find your model number prefix, just try a different list:

On some serial numbers, you can extract the date of manufacture:

Incidentally, the above web site has some rather interesting photos of appliance related fires. For example, hot water heaters do NOT start fires: and portable electric heater misuse hazards:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Well I went to all three pages, and searching on smith, none listed a.o.smith at all.

But I remember the clincher reason I thought that's what it was. The first owner of the house left me the owners manual for the original water heater, by aosmith, and the manual was amost identical to the one that came with both of my Sears water heaters. Same text, same fonts, same graphics

I'll check these out.

Yeah, I noticed that. However, it seems that Sears/Kenmore does sell AO Smith water heaters. Here's replacement parts for one AO Smith model from the Sears web site: and Sears repair service for AO Smith products: A clue might be that the Sears parts page shows the water heater by the AO Smith model number (ESM30) and not by the Sears style part number. The web page shows parts for 205 assorted AO Smith water heaters: none of which show a Sears style part number.

AO Smith also posts some of their instruction manuals:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

The ones that are good enough to be as bright, can be twenty or thirty bucks per bulb. But, if it means not having to go 24 feet up, might be worth it.

- . Christopher A. Young Learn about Jesus

.

It was the HOA's idea to put this light on my house, for secuirty reasons, because I live right next to the path that goes into the woods. (It used by JHS boys going in one direction, and HS boys going in the other, to their respective schools, but 2 years ago a big tree fell down blocking the path, with no good way to go around it, and now only one or two kids use it. ).

The HOA people were looking at the house in the next building too, but I wanted it here, so I could turn it off when I wanted too (not that I ever have.) And they pay me $10 per quarter for the electricity I use. It's been 20 years. I think they still do that. And the first time the bulbs burnt out, I called the HOA and they sent a whole electrician, with a ladder. Think how much that must have cost, just to change a lightbulb. And I think I called once more when the fixture itself had problems, but after that I couldn't bring myself to call them. Now I'm going to look at it that the 10 dollars a quarter is much more than the electricity costs, but it will eventually pay for the fixture. 2 1/4years I guess. And the work I put in. Another year. And then it can start paying for the time they towed my car away for no good reason, and the time they threatened to.

I was discussing a *gas* HWH, where you do want the heat from the burner to be conducted through the tank to the water.

I was thinking of the hot spots you could get with a gas HWH if the plastic isn't in complete contact with the tank.