Can you tell me what’s happening here? Smoky thread just below the surface

[Andy Davies]

Hi can you tell me what's happening here?

Before I start trying to make beads I'm checking out the annealing process with a little kiln I've made and I produced range of different diameter beads out of Effetre 104 CoE   Clear 591004.

I used the clear glass so I could check the beads with polarized filters and they've all annealed satisfactorily, but on this 18 mm diameter bead you can see smoky threads running around it just below the surface.

I don't think I've contaminated it but have I over heated it or is this a characteristic of the clear class?

The reason I ask is I see there's a 'Crystal clear' and the 'Clear' do you see a difference between clear and crystal clear?

All of the beads have the same 'smoky' defect but it's more noticeable on the larger ones.

I'm using a Hot-Head and propane, could it be the gas?


DSCF6307 by andy.c.davies@btinternet.com, on Flickr

18mm Ø

 All advice gladly received.


                                Kind Regards ... Andy

         
Update 17th Jan 2014 ... please see the other pictures further down the thread.

[Barnacle Bay]

1. You could be running to hot or too close to the flame.
2. Your not nipping off the first bit of the rod which tends to be a bit scummy.
3. If you are working on a 'Hot Head' .............  thats why I converted!   

[helbels]

Most likely you are working too close to the head of the hothead, try working further out. There is a difference between clear and super clear, but it's a difference in clarity and wouldn't have caused this.

[GaysieMay]

Check your torch end for dirt, with my minor I have an old kitchen knife and when the flame is lit I run it briskly over the torch end.  That will probably help.

I was once told that if your glass was too close to the torch you could burn it, but have since learned that it is more to do with the flame chemistry - not sure how you can alter that on a hothead, on a minor it's about getting the balance between oxygen and propane right.

Cross posted. X

[Barnacle Bay]

Andy I am very suprised that you do not already know this 

[Shirley]

All of the above, plus you might be getting towards the end of your propane.

[Andy Davies]

Thanks all...

I always reckon that if one person calls you a fool, you should take no notice, but if everyone calls you a fool then you probably are one.

And in this case it looks like the consensus is for this fool to keep the glass further away from the torch.

I'll check out the torch for cleanliness and have another go tomorrow.

                                  Many thanks ... Andy 

[Andy Davies]

Andy I am very suprised that you do not already know this 

Well just to let you into a secret, I have found that with the Hot-Head I can increase the temperature reasonably significantly by temporally covering two of the air inlet holes at the back of the touch and this makes gathering a larger amount of gas quite a lot quicker.

The down side to this is it changes the combustion and that may just have something to do with it what do you think? 

By the way I'm not recommending modifying the torch, it's just an observation.


                               ... Andy   

[Redhotsal]

Yup, you've "burnt" it. It's what happens when you haven't quite got enough oxygen to stop the glass from "burning" or, more accurately, reducing - the metal oxides within the glass partially lose their oxides to the oxygen starved propane resulting in a darker colour or, in some cases a metallic lustre depending on the glass that you are using. It's very easy to get this result with clear glass on a hothead as there really isn't enough oxygen available to keep the oxides in the glass.

You can make better use of the oxygen that is available in the hothead by working further up in the flame. But, of course - that is SLOWER as the working temperature is lower. On the other hand you will keep the glass nice and clear. If you observe closely the next time you are making beads, if there's an area on the surface which appears to be glowing much more than everything else then that will end up as a murky smoky mark. You can pick this off with tweezers while it is still hot - but better to avoid it altogether.

Unfortunately - this is why a lot of people graduate from a hothead to a dual gas torch as it is harder to work with a hothead - you have to be much more patient.

With regard to the type of glass - Effetre always had a glass ending in "004" - and ironically known as "Cristallo" - which is "clear" in Italian but sort of implies that it is "crystal clear" in English. It's not - it's really quite scummy and can burn like a so and so. This was the glass that many of us cut our teeth on, and then a few years ago they reformulated the clear and brought out "006" which in fact is much better - though you can still burn it and make it scummy if you try hard enough. I love 006 - it's never a problem for me - though a few people choose to buy clear glass which is practically impossible to burn. Reichenbach, CIM, and Double Helix all make a 104coe clear which many say is much much easier to use. They are more expensive so I don't bother with them. I don't really understand why Effetre didn't replace 004 with 006 as both are still available and there's no much difference in price, but then, who knows how they work in Murano?

I expect you got a fair amount of 004 in your mixed bag of Effetre - next time I'd go for 006 - but if you go further up you will get a clearer clear - and yes, covering up some of the holes will actually make the "burning" problem worse.....makes it quieter, though

[Barnacle Bay]

It's getting a wee bit hot!

Still surprised you would not know this, esp from an engineering and Scientific/chemistry point of view.

But this has already been covered in older threads you reallly must run a search! Folks will jump in, but, do a search, the nswer is already there!

[Andy Davies]

 
Thanks Sally that's very helpful.

             I appreciate your positive assistance.

                                   . . . Andy   

[Summershed]

We really must start a Redhotsal appreciation society, she is ace!!!

[Margram]

Andy, I've not used a hothead but understand that lots of users make a kitchen foil collar which you can leave in situ and just bring up to cover the holes when you want to deliberately reduce a glass (silver glass for instance) 

[Andy Davies]

Andy, I've not used a hothead but understand that lots of users make a kitchen foil collar which you can leave in situ and just bring up to cover the holes when you want to deliberately reduce a glass (silver glass for instance) 

Thanks Margram, what I found is with just two holes covered, it makes the difference as to whether or not I can melt 2mm Ø copper wire.  The torch head runs hotter with just two holes covered but I have a hefty brass fixing that hold the neck of the torch and acts as a heat sink, I figure heat could possible affect the seals in the gas valve if it's been run straight off a MAPP cylinder for any length of time.

             Thanks for the interest and useful feedback

        .  .  .  Andy

[Andy Davies]

It's getting a wee bit hot!

Still surprised you would not know this, esp from an engineering and Scientific/chemistry point of view.

But this has already been covered in older threads you reallly must run a search! Folks will jump in, but, do a search, the nswer is already there!

Don't you think that's bit ungenerous?

If you do a search for 'Smokey Threads' you won't find any leads.

I think that rather than acting as a self appointed administrator if you took a leaf out of Sally's book and the other good people here and offered constructive criticism you might find the world a much nicer place.

                      Regards . . .  Andy