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30 January 2011 @ 12:20 am
My MeLuna ball style original cup is beginning to tear near the ball and on the side of the rim. I'm a little upset about it because I haven't even had it a year yet. I've always been paranoid about boiling it, so of course, I think this may have caused it. I've always tried to be careful while boiling it, making sure it didn't touch the bottom or the sides of the pan, but maybe the temperature was too high. What temperature would be safe for this cup? Would it be unsafe to continue using it?
Taffyprincesstaffy on January 30th, 2011 05:27 am (UTC)
The temperature of boiling water is constant, at 212F or 100C. As long as there is plenty of water and the cup is not touching the sides or bottom, the cup should not exceed 212, no matter what the temperature of the heat source.
hazelwhohazelwho on January 30th, 2011 05:44 am (UTC)
*points up* What princesstaffy said. Also, the melting point of silicon is like 2500 degrees Fahrenheit.
godsinstrumentgodsinstrument on January 30th, 2011 07:05 am (UTC)
Meluna, however, is not made from silicon.
hazelwhohazelwho on January 30th, 2011 07:11 am (UTC)
Huh. I thought all of them except the latex Keeper were silicon. But a little googling shows you are totally right about that - MeLuna is made from thermoplastic elastomers, whatever that means. =)
fireaphidfireaphid on January 30th, 2011 09:21 am (UTC)
Also, cups (besides the Keeper and MeLuna) are made of silicone, not silicon. Silicon is a chemical element, which in pure form has known melting and boiling points well above the boiling temperature of water. Silicone is a name for a class of polymers that can have widely varying properties, including critical temperatures.
Maxine of Arcmaxineofarc on January 30th, 2011 06:00 am (UTC)
The boiling shouldn't make a difference. Once water hits boiling temperature, the temperature remains constant. No reason you can't continue using it, as long as the tears don't affect its usefulness.
m03m on January 30th, 2011 12:29 pm (UTC)
Have you contacted Meluna yet? They may be willing to work with you. You could take some pictures and e-mail them to the company.

It's probably as safe as ever, the nature of the material hasn't changed. But I guess it will become unusable eventually if/when the rim tears.
fee_parisienne on January 30th, 2011 04:47 pm (UTC)
Boiling water is always going to be the same temperature.
I think maybe a more relevant factor is time. The MeLuna website recommends only leaving the cup in boiling water for 1-2 minutes. Here's a quote from their FAQ: "For cleaning by boiling, just bathe MeLuna in boiling water for 1-2 minutes. Please be sure there is enough water in the container, so MeLuna swims without touching the ground."
heatha_featha28 on January 30th, 2011 10:17 pm (UTC)
Welll, boiling point isnt ALWAYS constant...but close enough that it shouldn't matter. Depending on your altitude(and therefore atmospheric pressure) the boiling point of water may change. Go up in altitude and boiling point decreases. However, if you put a lid on your pot or use, say, a pressure cooker that water will get a bit hotter.

However even with these slight variations, its likely that water tempereature is NOT affecting the cup. As long as the cup isnt sitting at the bottom or resting against the side the whole time it wont matter.

Whats more likely is that tugging and folding at the cup is wearing out the TPE, and perhaps it was a lower quality batch to begin with. You should definately contact the Meluna company about it, usually they are more than accomodating about issues with their cups.
saraf3msaraf3m on January 31st, 2011 10:45 am (UTC)

Pure water boils at 212oF at a "normal" air pressure of 1 Atmosphere
(= 1000 mBar = 1000 milliBar = 1 Bar).
At higher air pressures water boils at higher temperatures, for example in pressure cookers.
At lower air pressures water boils at lower temperatures, for example up in high mountains.

212 or 213 ish 212 to be exact

The lowest melting point for TPE or theroplastics is 105 Celcius = ~221 Fahrenheit

Definitely email MeLuna, Frank is great to work with and takes care of his customers.