Shifting COEs and garage temp

lacey · #1 2013-08-14, 7:47am

I'm a newbie. I make little monster sculptures because: 1) they make me happy, and 2) they're more forgiving (mistakes add character).

Anyway, I have so many questions, but for now I'll try to limit it to these 3:

1) I've read that if you work some of the boro colors too hot or for too long, you can actually shift the COE and cause compatibility issues (spidery looking cracks that happen in the kiln). I think I'm having this problem (I must learn patience and turn down the heat). My question is, are there obvious signs that you're working your glass too hot and/or for too long? For example, I've noticed that I've been boiling some of my colors (orange and yellow in particular). This boiling is probably causing the glass to shift COEs isn't it?

2) Pieces that you take out of the kiln that have the spidery looking compatibility cracks, can those be melted back down into blobs and made into something else? Or should that glass be thrown in the trash because the COE has been altered, and will stay altered even if I completely melt it down and rework it?

3) I've been garaging and annealing at 1050. I was having some issues with some green glass and a very helpful person here mentioned that green needs to be garaged at a lower temperature. So, I'm wondering if I should change my garage temp to 950 for all things? If so, once I'm done garaging and ready to anneal, do I just ramp up AFAP to 1050 and then anneal as usual?

Thanks in advance for any help. You guys are awesome and I've learned so much from your posts and advice.

Dragonharper · #2 2013-08-14, 4:22pm

Answers:
1.) If you are boiling you are working to close to the face of the torch. Work farther back and you will avoid boiling. AS far as working too hot, you just need practice with that particular color. When in doubt check the manufacturer's website for working the glass in question.

2.) About all they are good for is fish tank decorations.

3.) Again check the mfgr's website for garage temps. Yes you can do a full power ramp to 1050. Depending on thickness, although it's only 100 degrees.

Baywinger · #3 2013-08-14, 10:38pm

all of the crayon temps want to be brought to temp slowly in the torch or they boil so will many whites and blacks.
sometimes glass from different manufactures or even batches can not interact well.

lacey · #4 2013-08-15, 12:32pm

Thanks for the replies! That helps a lot!

I did some more searching in the forums and did some more thinking. I saw that some boro colors don't like each other. I have to admit, this monster (see attached), was created out of a bunch of the scraps that were sitting on my work surface. It also has a clear test tube (which was supposedly boro), mixed in with it. So yeah, guess I can't just throw a bunch of stuff together and not expect it to have compatibility issues, huh?

The pictures below show some of the cracks, especially the ones that show the back and a close-up of the side.

So what do you guys think? Do you think the cracks are due to me throwing a whole bunch of different stuff together?

lacey · #5 2013-08-15, 12:36pm

Quote:

Originally Posted by Baywinger

all of the crayon temps want to be brought to temp slowly in the torch or they boil so will many whites and blacks.
sometimes glass from different manufactures or even batches can not interact well.

Morgan, looks like this was what you were referring to when you said that glass from different manufactures or batches may not interact well, right?

Baywinger · #6 2013-08-15, 5:58pm

Quote:

Originally Posted by lacey

Morgan, looks like this was what you were referring to when you said that glass from different manufactures or batches may not interact well, right?

yes, not everything is exactly always 33 or 104 so if you place a stiffer color over a color that moves more the upper one can crack
Jenny at Tag told me to test compatibility pull a stinger of two colors together and toss it quickly to the floor(non flammable floor) if I remember correctly the stiffer color will pull the softer color so that is the one you want to layer first.
someone please correct me if I am remembering this wrong

lacey · #7 2013-08-16, 7:29am

That's good to know about the stringer test and thanks for explaining why. The way you explained it makes sense: a stiffer color on top of a color that move more will cause the stiffer color to crack.

So, is clear kind of neutral then? Can you put stiffer colors on top of clear or vice versa?

I guess to be safe, I should go back to a solid color base and then add different colored embelishments (after doing the stringer test of course). So much to learn!

Baywinger · #8 2013-08-16, 7:56pm

yes,you can also mix clear into stiffer colors to make it easier to work with.
also it is very common with boro to start with a clear base and add color on top whether it is a bead, or coloring a rod or tubing

GlassAlias · #9 2013-08-16, 9:39pm

Ill bet that piece cracked because of the test tube you mixed in. I dont see any other reason why that piece would have cracked so completely.

lacey · #10 2013-08-17, 5:22am

Yeah, I wondered about the test tube too. A friend of my husband's got like 600 test tubes at a flea market for $6. He said the box they came in said they were borosilicate. He gave a few to me to see if I could do anything with them. Well, the ornament I tried to blow with one was a falilure, so that's how it got mixed in with this monster. I don't think I'll try using them again.

Morgan - thanks for the tip about mixing clear with the stiffer colors - that's a great idea!

istandalone24/7 · #11 2013-08-17, 5:40am

keep in mind there is borosilicate in the 50ish coe range too. for lab ware.

lacey · #12 2013-08-17, 6:45am

Oh really?! Well that probably explains it - I'll DEFINITELY stay away from the test tubes then. Thanks so much for letting me know about that!