How hot is *too* hot? (For container jars)

[angelcandles]

I think I’ve found a great wick for my jar and wax. BUT, I lit my candle today at 11am and here it is 11pm and the jar is a little too hot to touch on one side (it doesn’t burn me but I would not keep my hand there longer than 2 seconds). I want my candle to be comfortable to touch and hold at all times. 11am - 11pm is a long time to burn a candle but we never know how long a customer will keep theirs lit. How do you judge that a jar is too hot? 

[pughaus]

as far as safety testing goes - for ex: if you were selling to a disney store- the candle vessel can't get hotter than 140 F  if my memory is correct.  However, they also test burn in 4 hr increments so a 12 hr marathon burn is really way above and beyond.  I think the point is, you don't want someone to pick up the candle and then drop it suddenly out of pain because it's too hot to hold.  I guess 140 is about the temp where most people find it unbearable

[birdcharm]

Many candle safety labels specify to only burn for a maximum of four hours per session.  Of course, some people will let that go for a while, but I think most would certainly extinguish well before the twelve hour mark ... I might be wrong about this, but it seems so to me.  Also, every safety label I've ever read states to not pick up or carry a burning candle, and even if someone were to attempt to do that, if the glass is hot, they'd probably give that thought up right away. 

 

At about the six hour mark, could you touch it for a moment without it feeling overly hot?

 

[BusyBee]

Per ASTM standards container temperature should not exceed 170F.  That seems little bit too high for my comfort range.  So, let's talk about coffee in order to have an idea of "how hot is too hot?".

 

Coffee is usually served in temperature between 150F and 175F, and many people would prefer near 175F coffee.  When they do Coffee tasting, they would prefer at 130F, and this is where I find my comfort range 130F maybe up to 140F for the candle.  The lower the better!

 

Yes.  There are many people who might burn their candle way beyond 6 hours at a time.  If anyone can come up with warm burning container candle for this kind of long burning time, then it would be special.  However, we all should be good as long as we can keep its temperature below 170F for more than 6 hours burn even up to 12 hours burn.  As long as we keep that temperature below 170F after so many hours, no one should blame us.

[Paintguru]

Any thoughts on how to measure this?  I've tried using my laser IR thermometer, but I'm not sure I believe it since it is going into clear glass.  Maybe a stick on thermocouple would work.  

Edited December 2, 2019 by Paintguru

[pughaus]

I use a laser IR thermometer and check at several points around the glass and top edge. It seems to work just fine.  This is how the testing labs do it.

[TallTayl]

1 hour ago, pughaus said:

I use a laser IR thermometer and check at several points around the glass and top edge. It seems to work just fine.  This is how the testing labs do it.

Same

 

It is pretty consistent

[xxxAlpha71xxx]

While not ancient, this is a bit of an old post that I just ran across but I thought I'd toss in an additional option.  If you have a thermometer that takes a type k probe you could also use something like this, most likely.  

 

https://www.amazon.com/URBEST-NR-81532B-Thermocouple-Temperature-Manufacturing/dp/B01M0IPBEC/ref=sr_1_7?dchild=1&keywords=surface+thermocouple&qid=1592449168&sr=8-7

[Paintguru]

9 hours ago, xxxAlpha71xxx said:

While not ancient, this is a bit of an old post that I just ran across but I thought I'd toss in an additional option.  If you have a thermometer that takes a type k probe you could also use something like this, most likely.  

 

https://www.amazon.com/URBEST-NR-81532B-Thermocouple-Temperature-Manufacturing/dp/B01M0IPBEC/ref=sr_1_7?dchild=1&keywords=surface+thermocouple&qid=1592449168&sr=8-7

 

Oooo, I like that.  I have thermocouple readers I could probably bring home from work and use.  May be worth an order.

[ErronB]

I just use my hands lol. If it's too hot to pick up at any time during the burns then it's no good to me. I can see how this might be problematic for smaller jars where a wick can lean over and make one side really hot, but I use 8oz tins with smaller wicks mostly so I don't really have anything like that happen.

[TallTayl]

Here’s a lesson I learned the hard way... I point my IR thermometer at different points on a jar around the entire circumference. The difference in temps from a simple, common curling wick like cd, cdn,CSN, HTP, lx and Eco was sometimes more than 50*F in the direction of the curl. Curls are not necessarily extreme and wicks not “too long”. It is a design feature of the wicks to inhibit carbon build up,

 

Some jars I could easily pick up, unless my hand grabbed the direction of the lean. when most of the jar was 150*F or so, and the side of the lean got to 200* or more, Houston we have a problem. 
 

The temp differences are more extreme when jars are more narrow. In theory twisting a wick, if we can control the rate of uncurling, could solve the problem. I have tested out intentionally off setting the wick tab to center the curl with some success, but it is very difficult to see the direction of the braid on many wicks. If I stick wrong it makes the problem so much worse. 

[KrisS]

On 11/28/2019 at 5:32 PM, BusyBee said:

Per ASTM standards container temperature should not exceed 170F. 

 

Bingo. You need to meet or exceed this standard and make certain to document your temperatures during burns.