moretti dark pink

sailingzees · #1 2005-12-11, 5:54pm

I am relatively new at lampworking but I have managed to make a little bit of progress. I thought I had moved well past the stage where I was thermal shocking glass rod as I began to work them in the flame. However today I was using Moretti dark pink, a color I had used before and it was thermal shocking real bad. It was not colder than normal in my studio and I had no problem with other colors I was using. I had melted a gather of glass and was winding it onto a mandrel and a piece of rod about 1/2 to 3/4 of an inch "exploded" from the tip of the rod. That would include a nice molten bit of gather that promptly began melting it's way through my shoe. I reintroduced the rod VERY slowly and took great care to pre-heat it and as I started working a gather onto my mandrel the exact same thing happened.

I had used this exact same rod a few days earlier to make a bead and had no problems with it. The conditions in my studio were no different from normal. Is this color more prone to thermal shock? Has anyone else had this issue with Moretti Dark Pink?

Kevan · #2 2005-12-11, 6:09pm

It it a very shocky color. Pink, Opal Yellow, Coppergreen, the new tile roof color.

A tip someone told me here is to turn of the oxygen and use propane to warm it up. It's gets shmutzy though. If not that, just really take your time warming it up.

sailingzees · #3 2005-12-11, 6:27pm

Here is a close up photo of a cross section of the rod that shocked and "exploded" off. The rod has what appears to be 4 air spaces running down the length of the inside of the rod. I have pointed out 2 of these air spaces that show up on this photograph. Is this normal? Would this cause a thermal shock problem?

I used the end of one dark pink rod and the beginning of this same rod that is now thermal shocking a few days ago to make this heart. I wonder if there were no trapped air spaces in the very beginning of the rod?

earth*monkey · #4 2005-12-11, 9:41pm

I'm wondering if it would be possible to anneal the rod in a kiln? Would that reduce the shockiness?

sailingzees · #5 2005-12-12, 1:20am

I think I am going to try that. I didn't even think about annealing it prior to use but that sounds like a great idea. This rod seems to have MAJOR stress in it. It is odd because it will heat up o.k. without shocking and I will even start using it and get a couple of winds on my mandrel before it shocks. I have been very careful not to move the rod to far into the flame but it keeps doing it. I bought several dark pink rods during this last purchase. I think maybe I will anneal all of them before I use them.

Thanks once again

DesertDreamer · #6 2005-12-12, 7:36am

Annealing really won't help...the bubbles will still be there. The bubbles ARE your problem....the air heats up faster than the glass does and expands RAPIDLY, causing your rod to explode. The best thing to do is to preheat your rod on as much of the length as you possibly can. I have a rod rest on my kiln (Arrow Springs kiln) so I can slide rods inside to preheat them. It can also help (though not as much) to preheat rods on TOP of the kiln, if you have a fire brick one, though this isn't as much heat. The one problem is, as soon as you melt beyond that preheated point, you're still going to have the shocking problem. Air bubbles suck.

taneres · #7 2005-12-12, 8:16am

I've have had some sage or avocado (can't remember which) that was like that. It sure can scare the bajeebers out of ya' when your just calming winding some glass and then it all explodes in every direction! Some rods are just not worth working when if they are bad enough. Sharp hot glass just shouldn't be projectiles!

Serena

Rebekah · #8 2005-12-12, 8:31am

I have a bunch of rods that do that. Just duck and cover. Pretty much all you can do.

Rebekah

FantM Designs · #9 2005-12-12, 11:44pm

I picked up a bunch of Moretti dark pink from Arrow Springs in October and it is the shockiest bunch of glass I've ever had. Same as you, the studio conditions are the same as always, not too cold, etc, and I swear, even keeping the rod in the outer 1 inch of the flame, it shattered 3/4 of the rod before I just threw the whole thing away. I couldn't even heat it enough to melt it. Crazy. I haven't tried dark pink since then... I have no suggestions, except that it may be the batch. I've never had a problem w/ dark pink before and I use a lot of it.