Cracking Question
 

I made this the other day and I'm not sure where my problem occurred. I did use my annealing bubbles instead of the kiln. I'm not sure if cooling was the problem or glass compatibility.

https://c6.staticflickr.com/1/305/30...fa98066802.jpgProblem pieces. by Ruth Pletz, on Flickr

Then this happened:

https://c1.staticflickr.com/6/5492/3...66f722bfa4.jpgProblem pieces. by Ruth Pletz, on Flickr

I used Uroboros clear and this mysterious pink. I got this pink in an assortment from someone who didn't do lampworking anymore. No markings. (This is why I label all of my rods.)

https://c3.staticflickr.com/6/5608/3...d22ce9c420.jpgProblem pieces. by Ruth Pletz, on Flickr

Any ideas?

Looks like Lauscha pink. Was the uroboros 104? If it was system 96 that would explain the incompatibility cracking.

It is the 104. That's the only kind of rods I get. It's why I considered the problem to be the pink. I don't really use them as they're kinda chunky.

Looking at the size of the piece I think not using a kiln might be a problem, you should let it sit in a hot kiln for a least 30 minutes before you ramp it down slowly.

I guess it is possible that there is an incompatible clear that got into your inventory.

Seeing that kind of cracking only around the "equator" makes me think you changed clear rods between embedding the murrini and wrapping the "equator".


But stress cracks from cooling without an annealing cycle could take just about any shape so I don't think its too weird.

Someone else with a better memory than mine will have to jump in here but didn't there used to be a problem with some ASK clear that not only would not play well with other clear glass but it would not even behave with itself from the same stick?


It's a lovely pink either way.

Sadly, this is all one rod of clear. I melted a big glob onto a punty and picked up all 5 murrini at once. Once I had a decent shape I added the pink. :( I'll have to try again.

Thank you all for your input.

It kind of looks like it might survive a slow reheating in a kiln and remelting if you can.


Any chance the murrini was 96 or something like that?

I know a lot of the frit I use is 96 and it's OK if I keep it under 10%.

I wonder if the murrini isn't furnace glass from a hot shop with a lower coe.

I'm pretty sure it's 104. I try and make sure that everything I get is 104. Ugh. That would be a bummer.

I think I am going to try the microwave kiln. I figure at this point it is already messed up, so what can I lose? I have lots of good luck melting other stuff in it.

I double checked. It's 104 murrini. I get almost all of my soft glass from Frantz, so I am confident that it is as advertised.

My only other thought is that even glass within the same coe can have different rates of physical characteristics with heating and cooling rates and even viscosity differences while cooling.


The difference between opaque white an just about any transparent.

My gut says its an annealing issue but I don't have the experience to back that idea up with anything tangible.

This glass stuff, she be a fickle fairy me thinks.

This, it's thick!

And the pink, if it's not lauscha, it's effetre pink alabastro or opalino, which you 'cannot' encase opalinos/alabastros. The end of the rod to me looks like it's one of those. I don't know lauscha well to know if it is that, I had issues with it not working out with my italian glass.

Do you know what kind of clear you used? I have had that kind of cracking with Lauscha.

If I look close at the picture it seem to have a bottom hemisphere of the pink with the murrini centered on that and the an upper hemisphere of clear encasing the murrini.


If that is the way you made it then I am not surprised that the upper hemisphere of clear cracked under stress without an annealing cycle right from the torch.


Even if the clear and the pink are listed as the same coe the minor difference in the way they cool would cause this kind of cracking.

I have a batch of Uroboros 104 clear that is not very compatible. I have found if I start with it and end with it, it comes out the best.

I think that in the end it was just too cold that night. I went back and did some tests. I used the same pink, Uroboros and murrini and then I used Electric blue, some other murrini and Zephyr. I made four pieces altogether. They are all the same thickness as the original and they all went into the annealing bubbles. All came out fine.

When I made them I take a large gather of clear and use that to pick the murrini up off of the hot plate. Once I have them melted in I added the back.

Thanks everyone for the advice. :)

It could have been because you did not have your tongue stuck out of the left corner of your mouth far enough and that the moon had not brought enough mosquitoes out to feed the flaying bats.


Sometimes stuff just happens.