The amazing exploding marble trick

Lotti · May 30, 2014, 06:41:04 AM

It was one of those days, builders all over the place and my DB popping in every 5 minutes to ask me something!!!! I am sooooo careful not to mix my 104 with my 33, but the only answer to what I found in the kiln must be incompatibility, but now I shall have to test all my clear rods to check and my worktop is littered with them (different sizes of course). Could there be any other reason for this?

It has sheared almost perfectly in half

(such a pretty colour too

).

Sorry for the rubbish photos, bit early in the morning for me but am about to leave for market and won't feel like doing much when I get back this evening!

I am sure it must be incompatibility (no air bubbles, unusual for me, but not this time!), it was a particularly annoying marble and was proving a pain to get round, but I didn't notice that half the marble seemed softer than the other which I am sure I would have

Pat from Canvey · May 30, 2014, 07:41:20 AM

I've had the same problem Lotti so now I put an end loop in all of my 104 COE clear rods and my Bullseye glass is kept under my work bench!!!!

garishglobes · May 30, 2014, 08:19:23 AM

I think it could be that there was a lot of stress in the marble and perhaps if you had a lot of distractions, it wasn't kept evenly heated? I am guessing that where it has cracked, pretty much along the colour, would have been a place where there would be most stress. Could be incompatibility too but I think I have had marbles do that to me when I know I just haven't had the heat right

james M knox · May 30, 2014, 09:16:44 AM

Lotti

I get this on occasion as well, and I don't have any Borro at all so it may only be an issue with not evening out the stress in the glass fully before cooling/ annealing the marble.

JMKnox

Steampunkglass · May 30, 2014, 10:23:42 AM

I get this too, I find flower marbles are a bit more stable but some colours can be worse than others in causing this. If it's a colour with sparkle it's best to avoid them for deep encasement as they are more likely to cause cracking, as the chromium in them as long garaging can cause areas of the glass to change to COE 54-55

Same can happen with some greens, but not so often. Its a mater of finding the ones that cause problems and either avoiding them of getting them straight into the kiln. You said you had problems rounding out, the only other thing was maybe you'd intensely heated one side/area of the marble and that helped it pop? It can be worth trying to make sure as much of the marble is evenly warm before it goes into the kiln to help prevent this if you've had to pin heat an area (such as when smoothing out the punty mark)

Lotti · May 31, 2014, 08:32:51 AM

Thanks folks, certainly could have been stress due to uneven heating as was trying to discuss floor tiles for the shower room at the same time as making this one! However, once I got to market yesterday and took some of the other pieces out of my bag to put on the stall I noticed a crazed back to one of my dichro pendants (a dichro I have used alot and never had problems with), backed with cobalt frit and also a dolphin who'se nose was crazed (poor thing, will just have to live in our house!). I am pretty certain now that it was incompatibility, I thought that as the dolphin was a frit one and I had dipped the nose rod in the frit that I would be able to tell on my bench which was the offending rod, but there aren't any with frit on the end!!!!!! So I am going to have to test all my clear glass rods on my bench now - ARGHHHHHH (mind you I do know that it was a 4/5mm rod so thankfully that narrows it down a bit as I don't use many of these). Lesson learned though too to ensure even heat! Will just have to make another one of these, the flower petals are so pretty

fionaess · May 31, 2014, 09:34:28 AM

If you had mixed 33 with 104 you would have got really crazy paving. And don't ask how I know. Lol. Looks like a thermal issue to me

spexy · May 31, 2014, 09:54:45 AM

What a pain! Can I ask how you go about testing your clear glass?

Lotti · May 31, 2014, 11:40:31 AM

Quote from: fionaess on May 31, 2014, 09:34:28 AM
If you had mixed 33 with 104 you would have got really crazy paving. And don't ask how I know. Lol. Looks like a thermal issue to me

The dolphin and the pendant both have crazy paving! To test you make two stringers ( one of a glass you know the coe of) and melt them one on top of the other, difficult to explain without pictures, if compatible they will stay straight as they cool if not compatible they will curve. My lovely contemporary flameworking book has a nice description ! Someone might be along later who can explain this more coherently

james M knox · June 02, 2014, 01:41:07 PM

One compatibility test explained here

http://www.davebross.com/GlassTech/glasscompatibilitytesting.html

JMKnox

Lotti · June 02, 2014, 04:51:48 PM

Quote from: james M knox on June 02, 2014, 01:41:07 PM
One compatibility test explained here

http://www.davebross.com/GlassTech/glasscompatibilitytesting.html

JMKnox

Thanks James, pictures always help and a much better explanation than my feeble attempt

ajda · June 02, 2014, 06:52:45 PM

More detail here... He starts with little rectangles of sheet glass, but the first torch demos he does are actually with rods, so hang in there for at least 5 mins!

http://www.youtube.com/watch?v=ViPiaFS16zQ