My Libby glass 11oz tumbler exploded (wow)

[bramoncada]

Ok..... so I'm doing quite a bit of testing on my candles... This happened during a test with ecosoya and lx-22 wick ( hence all the soot) . It was burned down to the tab and all of a sudden pop! I just ordered a bunch of these and now im concerned if this is safe or if i just had a defective glass.... Has this happened to anyone else?

[pleasureridgecandles]

Oh wow! Hopefully that was just a defective one. I can see where'd you be leary of putting these out for customers not knowing if that will happen to them. I don't use those jars so I can't help. Hopefully someone can help.

[Bernadette]

I can say I've never had it happen with any of the candles I've made, but I have had it happen before I made candles, and purchased them.

And they were thick glass, Libbey, and it always happened in the last third of the candle. All of a sudden there'd be a loud pop, and glass was everywhere!

[Johnna]

I give my customers burning instructions that say to discard when 1/4 inch of wax is left in the container. Perhaps the metal alone with a flame is a stronger heat and thus leads to the exploding glass??

[Stella1952]

One mo' time...

From the National Candle Association's website:

Don't burn a candle all the way down. Extinguish the flame if it comes too close to the holder or container. For a margin of safety, discontinue burning a candle when 2 inches of wax remains or ½ inch if in a container.

Having said that, with that much soot, I would have suspended the test far earlier because something was obviously wrong. It looks to me like the candle was way overwicked. There is no way that wax should have sooted the glass like that otherwise. Were you powerburning this candle? If so, had you previously tested for 3 hour intervals, trimming the wick before each session BEFORE you did a powerburn?

And they were thick glass, Libbey, and it always happened in the last third of the candle.

The thickness of the glass is absolutely NO guarantee that it can or will hold up to higher heat than thinner glass. Sometimes the converse is true.

The last half of the candle is when the container really heats up which is why we advise folks to wick for the last half of the candle, not the first part.

Edited May 17, 2011 by Stella1952

[NaturallyTru]

Having said that, with that much soot, I would have suspended the test far earlier because something was obviously wrong. It looks to me like the candle was way overwicked. There is no way that wax should have sooted the glass like that otherwise.

I was thinking the same thing...that bugger is black!

[bramoncada]

Yes, I was def. power burning the thing... I was pretty comfortable with the wicking until this... Throughout the LX sizes i wasnt trimming the wicks before each use because I doubt costumers will be doing that.. So i really wanted to put it to the test. I have since changed to CD wicks and will begin testing them and take STELLAS advice on sizing for the bottom half.

[Monvi33]

I agree with stella and naturally tru....that is way to black. To me Lx22 seems huge for that size container, IMO

[LuminousBoutique]

yeah... whoa.. but not unexpected considering there appears to be no wax left in the container and the amount of soot, size of wick.

[Stella1952]

Bramoncada, you are so correct: customers probably will not trim their wicks as instructed. That's why it's important to do testing in two phases: one where you perform all the due diligence stuff so you get good, reliable data. Once you arrive at a wick decision, THEN do a powerburn to see if any last minute tweaking is needed. Even when powerburned, the candles I make will not produce much soot at all (unless, of course, they are burned in a draft, then all bets are off) - only a little around the rim occasionally. Of course, this ALSO depends on the container being used. Most of my candles ae poured in 8 oz. widemouth containers which are no taller than they are wide. The incidence of soot during a powerburn increases in taller containers, like the status (metro) and taller hex jars I also use. Your tumbler is about even, so it really had to be overwicked to produce that amount of soot!

I frequently powerburn mine on my front porch where I DO get some breezes simply to see how much soot I can expect if someone pays zero attention to the instructions and warning label. I have a friend with an enclosed back porch who burns her candles directly under a ceiling fan. The last time I visited her, I was studying one of my candles centered on her wrought iron table to see why it had tunnelled so badly... my soy candles NEVER tunnel! Then, I noticed the damned fan directly overhead... I studied the candles she had lit off to the side, and they showed more sooting but less tunneling. Ahhhh... the best laid plans of mice, men and chandlers go straight down the drain when people ignore instructions!!

Another word about powerburn testing: when performing these at home, DO take some precautions in case of worst case scenario. Place the container in a pan of some sort with sand in the bottom or a little water. If the container does shatter, the liquid wax mess will be contained and less likely to catch fire. Some of the glass may end up outside the pan (I use el cheapo aluminum pie pans), but the fuel will remain within the pan. When I powerburn on the porch, I place the containers inside a large glass hurricane (couple of inches of airspace all around). It still is affected by breezes (although not as badly) but in worst case scenario, the wax will end up inside the 'cane and not all over everything.

Best of luck with future testing.

PS Pour testers with CD 12, 14 & 16 and see which one works best for your container and wax.

Edited May 17, 2011 by Stella1952

[Candybee]

Wow! That is way too much soot. Definitely wick down or choose another. LX were designed more for pillars. Also, I was wondering what the neck size is on your tab. Was is a 3mm, a 6mm or a 9mm?

[Stella1952]

what the neck size is on your tab. Was is a 3mm, a 6mm or a 9mm?

If it wasn't sealed at the bottom (which I doubt at the temps involved unless high temp silicon sealant was used), the wick would continue sucking liquid wax from underneath regardless of the neck height...

For those who haven't seen the photo below (I've posted it many times), this illustrates why having a good seal between the wick tab and the glass is so important, especially in powerburn situations (or when a customer ignores instructions and warnings). It's also a good illustration of how the temps inside the container rise toward the end of a candle:

This was a palm wax candle poured in a metro (status) jar that I powerburned. The wicktab was attached with high-temp hot glue. As you can see, the adhesive softened, then let go. The wick continued sucking wax until there was nothing left to suck and wandered off-center (due to convection) to the side of the container. You can see the accumulated soot (from 11 o'clock to 6 o'clock) around the top third of the jar (the black stuff on the left is writing on the outside of the container).

If the seal remains intact (ie. does not soften and leak), the wick WILL self-extinguish at the top of the neck as designed; but if the adhesive softens enough (or lets go altogether) to let liquid wax be drawn up by the wick from underneath the wick tab, it's going to continue burning until there is no source of fuel remaining. That obviously happened with Bramoncada's candle... with potentially disastrous results.

This is WHY we test, BTW... While it's wonderful to post photos of our beautiful candles, it's important to post photos of the failures as well, so people new to candlemaking (and a few not-so-new) will understand the importance of testing and how short-cuts and assumptions can have unhappy results...

Thanks for posting YOUR boo-boo, Bramoncada - I hope a lot of folks learn from it!

Edited May 17, 2011 by Stella1952

[EricofAZ]

LX22 is a huge wick for a container. if you look at the flame height and melt pool, you might find that the MP increases when in a container and that wick would be good for probably something like a 3.5 to 4 inch diameter.

http://www1.stimpson.com/~stimpson/WicksUnlimited.pdf

There are three times that I want to hold the glass.

First, the first burn at about the half hour mark. This is enough to heat up the top of the glass but not enough for the whole container to turn into a heatsink. I want to see how hot it gets at the top.

Second, at about the two hour mark when the glass becomes a heatsink and spreads the heat out (this is usually pretty cool).

Third is at the bitter end when the flame is about to self extinguish.

In all three touch tests, I want to be able to hold the container without it feeling uncomfortable. If I feel like I might want to let go or get burned, its way too hot.

Edited May 18, 2011 by EricofAZ

[coconut]

I have to agree with the last two posts. It is important to be able to touch the glass. Also very important not to have wandering wicks. I use an unusual method to attach my wicks and have never had a wanderer or a wax-sucker. I use a dab of mold sealer to attach my wicks. It is important to remember that glass can crack or break if subjected to temperature changes, and can explode if subject to heat extremes that are concentrated in one spot. A flame that is too big or wanders, can touch the glass and because the temperature of this flame is between 800 and 2550 degrees (per the "internet"), it is no wonder the glass exploded!

[lsbennis]

Holy Cow! :shocked2: I use those jars all the time and never had that happen!

[Angelique]

Ive never had that happen either, Ive used the CD 16s in that jar with soy since 2005 and not had a problem, maybe try that wick for testing.

AprilH

[Angelique]

Actually oops, the jar I've used is the 11 oz Anchor Hocking double old fashioned, not the Libbey 11 oz (they look very similar to me) but the cd16 and soy have always worked very well for me

Edited May 23, 2011 by Angelique

[bramoncada]

I actually am in the middle of testing with CD wicks right now... the 12 is tunneling the 14 and 16 still have a little bit of wax on the side of the tumbler. However im thinking that an 18 may be way too big.

[Stella1952]

the 12 is tunneling the 14 and 16 still have a little bit of wax on the side of the tumbler.

Keep on burning them in 3 hour increments until the bitter end. Photos would be great!