New style of Chinese mantles

Looking again at the listing, they were sold as ‘no radiation mantles’....a lie then?

 

@MYN could you interpret the results you were getting from the different types of mantles? Not having a Geiger counter I don't know what the readings mean.

 

Hi Colin,

many thanks for the links you provided. Very informative indeed!

 

Looks like he is measuring microSievert/hour, but Alpha, Beta or Gamma radiation ?

 

The understatement of the century !

The ties may be strong but they are ridiculously short, also, they are very smooth and shiny and it's damn near impossible to make a tight knot. That said, once fitted and working, they are about the same size as a Coleman 99 - maybe a bit bigger but not much - and do give a very bright light but 45 minutes to tie on two mantles is beyond a joke !
I shall now be spending the next few days joining a length of sewing thread to each end of the tie on the remaining mantles so I have something to work with. As far as I'm concerned, this inconvenience negates completely the low price and I feel I would have been much better off if I'd paid double (or even more) the price for mantles I could have got out of the packet and tied straight onto a lantern without the need of a load of fannying about. If you have big hands / fingers or arthritis don't waste your money on these mantles.

Henry.

 

Its micro Sievert/hr as indicated on the scale. Multiplier selector to x1 to disregard any background radiation. As you see from the pictures, there's a Coleman #21 to indicate zero.
I can't say if they're emitting alpha, beta or gamma rays but Radon-220 gas and Radium-224 are some of the radioactive daughters with its decay. Note that the radiation penetrated the plastic packaging.
As long as you don't eat or inhale the dust from a broken mantle too frequently and you don't leave a big bunch of them for too long within an enclosed space such as your house, they shouldn't be too hazardous to live with.
@ColinG ,
Now that you have acquired hundreds of them, it wouldn't be a great idea to store all of them in an enclosed space which you eventually would access. Store them outside or in a place that's well ventilated. You don't want to be bombarded with a sudden strong burst of radiation that had accumulated in the enclosure once you open it.

 

I maybe wrong since I am still learning about radiation. Having written this: radiation doesn't ventilate out.
Inside the house or outside doesn't change the radiation level. And if you enter the storage you get the same amount of dose.

What can happen is that your storage box gets radioactive.
However the levels and intensity are to low (I think).

I will do some measurements with my set. That is measuring uGy/h or CPS.
The Counts Per Second gives the known beep beep beep.
In the kitchen it now counts 0,10-0,15cps background nosie. I think or hope or something is releasing electrons or neutrons.

Biggest issue is calibrating your set.
I haven't searched but my guess is that calibrating a set is expensive.
So I can measure relative but not absolute.


My set: FAG Kugelfischer PDR 7001 from the Dutch military.

 

I have plenty of Chinese mantles with more on the way, maybe I need to build an ionization chamber. I don't think you need an exact count, just the ability to see a relative increase above background. Yes?

 

Well actually you are right, Wim. Ventilation does not change the amount of radiation(alpha, beta, gamna) emitted. I advised that the mantles to be stored outside or some well-ventilated areas so that most of the radioactive isotopes of whatever amount of radon, radium, etc resulting from the decay of Thorium dioxide do not linger around in the house or any enclosed space to cause further concerns. These daughters are pretty nasty as well and would in turn decay further to other elements and emit radiation (alpha, beta or gamma) in the course of it. I would not consider their half-lifes in order not to complicate matters further.
To be on the safer side, I suggested that the mantles not be stored in great quantities in an enclosure so as not to increase chances that any stuff from their radioactive decay being build-up inside and then released in greater than usual doses as you open it to retrieve the mantles.

 

Yep, calibrating your equipment can be costly, Wim. If you're not using it for business-related operations, then its not really necessary to get it that accurate.
We only wanted to ascertain if the mantles are radioactive or not.
The meter shown in the pictures I posted earlier does not belong to me. I just borrowed it from the Plant which I'm working in. Its calibrated and we're using it as part of the requirements in operations as we have radioactive measurement / sensing systems (non-intrusive) here for our in-process materials. Its imperative that any traces of excessive radioactivity levels in the case of leakages be detected and reported to the Authorities.

 

Arthritis, that leaves me out!
I can't tie my shoes without a problem!

 

About the radiation: I'd need to see a little more information before I began disposing of my stocks just yet.

About the tying: Yes, they are as fiddly as heck to tie but I found that by twisting the thread in on itself not just once but two or three times, the thread can be pulled tight without slippage - allowing you to make the final knot.

I still need to do one more test with CF/Naptha to see how they behave as I said I would. I'll post the results when I get round to it but it's cold here and I've had a tiring week so far!

 

For this test I chose the only single mantle naptha lantern that hasn't been converted to kero - my AshFlash.
The new pink tops seem to be weaker than the green tops as this one blew a hole just like the first one did. This directed a plume of hot gas directly at the globe so I switched it off immediately. The globe is original and I didn't want to destroy it!

While it was working it was very bright just like the 335/9.




You can just about see the hole in the mantle... it's at the bottom.



For those of you who might have been wondering, I fitted a pre-heater cup to the AshFlash some time ago to stop the start-up drama that used to occur every time I lit it!

 

You need not dispose any of the radioactive mantles @ColinG . Those would be hard to come by in the future if China decides to completely phase them out.
The radiation is absolutely normal for Thorium types. You only need to be a little cautious when handling, using and storing them. I personally prefer radioactive types despite whatever hazards that might arise from its use.

 

@ColinG twisting the thread in on itself not just once but two or three times is a trick I learned more than 50 years ago and still use today, especially when tying-on mantles but the ties just aren't long enough, also, the thread readily unwinds itself into its individual strands making them even more useless. I'll soldier on with the ones I have - maybe adopting your little trick with the wire ties - but I won't be buying any more.

Henry.

 

Thanks for all your input guys. It was a very enjoyable and informative read! I have now moved my new stock of Butterfly Chinese mantles to the summerhouse in the garden. I will also make sure the first preheating is done outside (again in the summerhouse). Just in case.... however I’ve read that taking a weeks holiday to Cornwall exposes you to a higher dose than a chest CT scan...and since I go to Cornwall every year, I probably shouldn’t worry to much about handling mantles!

 

Just a thought: a outside shed of garden hosue or any out building can be way more moist then indoors, central heatde house.
One thing mantles don't like is moisture so take that in mind as for storage.

First burn off should be one otside always. Itsis a smokey operation after all.
Radiaton will always be present.
So at the moment the garden shed is "self lighting" you can move the mantles to another storage.

 

Just recieved a package of these "non radioactive" mantles and they off the scale my meter at 9.99µSv/hr. It would be interesting to have them analyzed by someone with the correct equipment and knowledge.

Link for the mantles I bought 20pcs Home Lantern Mantles Kerosene Lamp Mantle Paraffin Lamp Gas Lamp Cover Set | eBay

 

In be gone back to using one of the green tops on my AshFlash.

 

As a rough estimate, its stated somewhere that the dangerous dose of radiation is about 100milliSieverts being accumulated in the human body over a period of one year. 100milliSv=100,000microSv.
Assuming a year has 8760hrs, then its about 100,000microSv/8760hrs = 11.42microSv/hr.
That would be roughly equivalent to strapping a piece of radioactive mantle permanently on our bodies for a year. I don't think anyone here wears a piece of mantle necklace 24hrs a day.
So I'd say, its still quite safe to be using these mantles, so long as we are aware and take necessary precautions in their handling, storage and disposal.
They are indeed bright and glow whiter than most, if not all, of the non-radioactive ones I know of.

 

Thanks for the more detailed information, @MYN - very useful.

 

Because the ones you’ve been testing have a weak construction/weave prone to developing a hole?

 

Yes. I need to test a few more to be certain but so far 2 out of 2 have developed holes - not a good record! Maybe I need to be a little more gentle when I 'inflate' them for the first time.

 

Well I get my geigercounter without any problems over the first warning: 20uGy/h (Gamma+Beta sensor used), on a package of mantles.
Now I haven't found a conversion between Sievert and Gauss.

 

@ColinG
Thank you for your reply Colin. Seems to me the technique you described for burning off and inflation of the mantle wasn’t at all tough on a mantle.
With hindsight looking back at your original photos and reading @Henry Plews‘s comments those tie threads are awfully short and would put me off purchasing.
Bravo for a thorough test and write-up - and to those exploring the radioactivity issue! Fascinating.

John

 

When handling and disposing of burnt thorium mantles, don’t inhale the dust. Other than that, they should be quite safe with normal use.

People who fly in jet passenger aircraft are exposed to radiation at about 0.003 millisieverts per hour:

Air travel exposes you to radiation – how much health risk comes with it?

Cheers

Tony

 

I found a conversion site: convert-me.com
What confuses me is that uS and uGy would be the same unit. But one is absorbed radiation dose (Gray) and the other
Dose equivalent radiation (Sievert).

If I am correct I see @MYN measuring 2-5uS/h and @Thomas 10uS/h ?
I will do some measument tomorrow.

I have a Gamma probe and a Gamma /Beta probe
Sadly I do not have the Beta probe (DT7004)

 

Should someone who bought these provide feedback on the radioactivity to the seller?

 

It depends.
For the sake of returning the goods in exchange for non-radioactive ones, you might want to.
But on the other hand, that could eventually result(directly or indirectly) in even stricter ruling being imposed on such trading and we'll have a harder time obtaining Thorium mantles in the future.
I'd personally take it as a pleasant surprise. Thorium mantles, besides being generally whiter in their glows, are part of the history of gas mantles. They're close to how the classics would have appeared.

 

Myn,

I like that ‘ they’re close to how the classics would have appeared’, and thank you for your clear explanations about rAdioactive dose. Very informative.