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mikem
07-17-2006, 12:24 AM
Mom's plastic lid for her crock pot (like a coffee pot only for long-term cooking stews and such) broke and I am thinking about using some scrap Lexan that I have laying around to make a disk to replace the lid. She called the company and they don't make replacement lids for it anymore. This would have hot food right below it for hours on end. Would it hold up and is there any problem with off-gassing of plastic vapors into the food? At what temperature would it melt? Thanks--Mike.

Leigh
07-17-2006, 12:37 AM
Hi Mike,

I believe the maximum operating temp for Lexan is 180º F. I would think that rating is much too low for such an application. I realize the actual temperature will likely be lower than that, but you typically want component specs to exceed actual operating conditions by a good margin.

CCWKen
07-17-2006, 12:38 AM
I wouldn't think a crock pot gets hotter than about 250* so it should work.

CCWKen
07-17-2006, 12:40 AM
I believe the maximum operating temp for Lexan is 180º F. I would think that rating is much too low for such an application.

I'm probably wrong but I thought it was closer to 300+. ??? Or is that the melting point? :eek:

Tinkerer
07-17-2006, 12:46 AM
Lexan can and will sag and gas off when heated. Just a idea... why not make a ceramic or earthware replacement with a nice safe glaze. I'm sure you could find a pottery place that would let you make it or make one for you. Or make a stainless lid.

snowman
07-17-2006, 12:50 AM
TG of lexan is around 150C, aka, 300 deg F.

It will start to sag around 140, you should be fine.

If not, you'll just have to make one out of acrylic...that's what they are generally made of anyway.

Evan
07-17-2006, 01:40 AM
Not sure I would want Lexan (polycarbonate) around cooking food. It's made of bisphenol A and phosgene. Bisphenol A is a synthetic estrogen and phosgene is a lethal compound.

About bisphenol A:



More than 100 studies have explored the bioactivity of bisphenol A (http://en.wikipedia.org/wiki/Bisphenol_A) leachates from polycarbonates. Bisphenol A appeared to be released from polycarbonate animal cages into water at room temperature and that it may have been responsible for enlargement of the reproductive organs of female mice.[1] (http://en.wikipedia.org/wiki/Polycarbonate#_note-0)
An analysis of the literature on bisphenol A (http://en.wikipedia.org/wiki/Bisphenol_A) leachate low-dose effects by vom Saal and Hughes published in August 2005 seems to have found a suggestive correlation between the source of funding and the conclusion drawn. Industry funded studies tend to find no significant effects while government funded studies tend to find significant effects.[ (http://en.wikipedia.org/wiki/Polycarbonate#_note-1)

http://en.wikipedia.org/wiki/Bisphenol_A

SGW
07-17-2006, 09:41 AM
I think I'd try to find a replacement glass lid someplace -- if nothing turned up, maybe make one out of aluminum. But I think I'd avoid plastics.

Wirecutter
07-17-2006, 01:20 PM
I've worked a little with Lexan, and I consider it to be pretty low temp stuff. My experience was that, when it gets hot, first it get's a "foamy" texture. (Trapped water in the plastic, IIRC, making lots of bubbles in the material.) It then flows pretty slowly, but flow it does. Imagine a thick, hot, sticky, smelly, foamy film half an inch thick as a skin on top of your stew.

You might try browsing yard sales, thrift stores - that kind of thing. You'll find the perfect match just after you give up and fabricate one from aluminum. :D

-Mark

mikem
07-17-2006, 01:45 PM
The ceramic idea is interesting since I know a lady that has a pot shop and kiln. What are plastic pop bottles made from? Is that going to leach into the soda pop and kill us too? Thanks--Mike.

Peter N
07-17-2006, 01:53 PM
What are plastic pop bottles made from?

PET - Polyethylene terephthalate. Won't kill you any more than eating raw steak or living in cities:D

Peter

Wareagle
07-17-2006, 01:53 PM
What are plastic pop bottles made from? Is that going to leach into the soda pop and kill us too?

It seems like every so often there is another study that shows that this or that cause cancer, memory loss, premature aging, reproductive unproductiveness, or whatever.

Unless it is an unappropriate material, I don't think that plastics around foods are a concern until they are heated, or start breaking down.

If nothing else in this world kills us, the old clock on the wall will.

CCWKen
07-17-2006, 05:06 PM
I like the SS or ceramic idea. If you use ceramic, make sure it doesn't contain lead. Nix on the aluminum.

Next week, they'll probably find out all that plastic stuf is good for you. :D

Brings up and interesting point:
My B-I-L has been having bouts with pneumonia since a chemical accident at his work. He's also been on blood pressure medicine. He had an emergency a couple of weeks ago when he failed to take his meds. Rushed to ER. The doctor said that he is against smoking, but the fact that my BIL smoked probably saved his life. He smokes 1/2 pack and the doctor said to continue but no more than that. :eek:

Lets see, coffee is still good for you this week isn't it?

Wirecutter
07-17-2006, 05:15 PM
I wish I thought of the ceramics idea - that's the best one so far. I've done pottery work in the past and didn't think of it. Oh well.

FWIW, I believe what we'll find out within the next few years is that the State of California causes cancer. That or white lab mice.

-Markl

Alistair Hosie
07-17-2006, 05:19 PM
Why not turn one out of wood it should be a nice excercise and a good fit can be achieved wood will hold up well to high heat and can be used for this easily I would try that or get a manufacturer of pottery to make you one or just buy anew crock pot.or if you need a crackpot phone his lurdshup "sir johan":DAlistair

Millman
07-17-2006, 06:37 PM
I would vote for stainless or wood, Acid in tomatoes will eat through aluminum and cause an aftertaste. Must have fresh tomatoes, hate the gas ripened, don't you? Man must have crock pot chili in order to survive. I'll have to check again, but I'm sure it's in scripture somewhere.

Leigh
07-17-2006, 06:53 PM
I believe what we'll find out within the next few years is that the State of California causes cancer. That or white lab mice.
Cancer is endemic in white lab mice :D

john hobdeclipe
07-17-2006, 06:56 PM
So it's a coin flip between Lexan poisoning or Aluminum poisoning. Ya makes your choices and ya enjoys your diseases. Have your Mom throw several big Habaneros into the recipe next time and you won't care anyway.

If you still have the broken original, test it to see what kind of plastic it was made of. Someone here just recently posted a chart showing how to recognize different plastics, or maybe it was a link to a website with such a chart. I forgot already.

If it was clear, my guess is either polycarbonate or acrylic. Acrylic has a unique odor when it's hot, and you could burn just a little edge of the broken piece and compare the smell to a known sample of acrylic (window glazing?) A little whiff won't hurt. Just don't sit there and snort it.

It makes you forget where you saw links to stuff.

Evan
07-17-2006, 07:10 PM
Lexan won't poison you. The phosgene is locked up in the polymer. All that will happen is that you may grow larger than normal female reproductive organs.

John Stevenson
07-17-2006, 07:15 PM
If nothing else in this world kills us, the old clock on the wall will.

Never realised they were that dangerous Wareagle,
thanks for the heads up, I've just thrown the bugger outside.

.

Millman
07-17-2006, 07:21 PM
[[grow larger than normal female reproductive organs.]] Great Evan, that means I can call people BIGGER pussies than they already are!!!! You're just a wealth of internet information! Thanks

Peter N
07-17-2006, 07:23 PM
Never realised they were that dangerous Wareagle,
thanks for the heads up, I've just thrown the bugger outside.

Reminds me of a freind of mine, a heavy smoker, when he went to the Doctors for his annual check-up.

The Doctor said "Bob, you do realise that all this smoking is killing you slowly?"

And Bob said " Well, I'm in no hurry..."

Peter

Millman
07-17-2006, 07:32 PM
Peter, that was hilarious! My opinion exactly; so fed up with the Mamby-Pamby fools who agree with anti-smoking campaigns, while they pollute the world with their jets and SUVs,lawnmowers and factories that actually kill people. Anti-smokers just want to steal your rights away, and stupid people let them get away with it.

Tin Falcon
07-17-2006, 09:41 PM
I know this is the HSM board and we love to make things.We use a stailess lid from another pan, Revere Ware I think. So why not try to find a SS lid at a yard sale or flea market. Better than the original.
Just a thought
TIN

BillH
07-17-2006, 09:50 PM
Peter, that was hilarious! My opinion exactly; so fed up with the Mamby-Pamby fools who agree with anti-smoking campaigns, while they pollute the world with their jets and SUVs,lawnmowers and factories that actually kill people. Anti-smokers just want to steal your rights away, and stupid people let them get away with it.

IF you want to smoke yourself to death, be my guest, just dont blow your smoke over my way. Smoke is smoke no matter where it comes from and its not something you want inside of your lungs for any logical reason.

Evan
07-17-2006, 10:16 PM
Smoke is smoke no matter where it comes from and its not something you want inside of your lungs for any logical reason.

While it's true that smoking is a nasty habit and unhealthful it is not entirely bad.



Nicotine Improves Memory And Helps Brain Repair Itself

The remarkable protective effects of nicotine — the addictive chemical in tobacco — on the brain are continuing to surprise scientists. One recent study has found that one of nicotine's metabolites, cotinine, may improve memory and protect brain cells from diseases such as Alzheimer's and Parkinson's. Another new study shows that nicotine can help improve some of the learning and memory problems associated with hypothyroidism. Such studies suggest that nicotine — or drugs that mimic nicotine — may one day prove beneficial in the treatment of neurological disorders (http://www.aphroditewomenshealth.com/news/20031103220446_health_news.shtml).

http://www.scienceagogo.com/news/20031012195753data_trunc_sys.shtml

I for one rely on smoking my pipe (only, I hate cigarettes). It helps to clear what is known as "fibrofog" caused by my FMS.

mikem
07-18-2006, 09:21 AM
How about spinning one from a copper sheet? Would that be the best material and the easiest to spin? Thanks--Mike.

LarryinLV
07-18-2006, 01:37 PM
Hmmm.. Turned stainless, grooved for an 'O' ring of course. TIG a nice turned handle on top.....vent slot with etched degree opening marks.. Yes, I think a plan is coming together. OH, don't smoke while your building it.

Millman
07-18-2006, 02:25 PM
Just think, standing ankle deep in water, tigging, smoking, rag in your pocket next to a large fan, no helmet, no safety glasses, sandals, now THAT"S livin! .....for awhile at least.