REALLY new to Boro

Donna T. · #1 2010-03-23, 4:21pm

I've been lampworking 6 years but just tried boro for the first time Sunday. I'm having a couple problems and probably a dumb question.

If you are going to garage boro at 960 or so can you do boro first then turn down to 960 and work on soft glass the rest of the day?

Here are pictures of what I did this week. The two clear ones are fine but the bead and the focal both cracked. I used the same white in both of them which may be the problem or did the focal crack because I didn't put enough heat where the bead met the formed piece and where the punty was? I don't know what white it is as I was gifted all my rods except the frit.

I'm also having trouble rounding up the bead. Is my torch not hot enough? I'm on a Bobcat with one concentrator. One of my favorite things to do with soft glass is gravity but I'm having trouble getting boro to flow.

Any ideas or point me in the right direction would be most appreciative.

pierces*designs · #2 2010-03-23, 4:49pm

Donna, I don't use soft and boro in the same session anymore, but I used to just set my kiln for my soft glass settings and do both. Then put the boro through a second batch anneal to boro temps later.

With boro, the motion to round is not back and forth, back and forth trueing up that you are used to. You need to spin the mandrel in one direction only.

This is what I do. Often I will start with a thin stripe of clear, then encase in white, then encase with a color or two, then encase that with clear. I do two different types of encasing. If I want thin, I take a 5mm rod and encase from right to left, once layer. If I want a thick encasing I use a fatter rod and do two rounds (one on top of the other). Be sure to keep it fairly even.

While I am laying down the beads, my mandrel is in my left hand and my glass is in my right. When I am ready to round out my bead, I put down the glass and put both of my hands to the right of the flame. My left hand is pretty much just a fulcrum for the mandrel to lay across and my right hand is spinning the mandrel away from me. I use my left hand to keep a continuous spin going. You want to be close to the flame and keep the mandrel BELOW the flame (or you will burn through them).

I do stop in spots during my spin to even out my round like in soft glass, but the stops are very short.

Donna T. · #3 2010-03-23, 5:06pm

Thanks for the help Debbie. I did burn one mandrel into. LOL I was using one of my smallest mandrels like I use for earrings. I switched to my BHB mandrels till I could get a feel for it. I noticed it took more heat on the bead for it to pick up frit. I thought I would have it hot enough but when I rolled it it wouldn't pick up any.
I love the colors I got from the frit though so I'm going to keep trying. It would be nice to play with boro though for a couple of hours and then get some work done in soft without losing the whole day to just boro. I'll try the extra annealing cycle like you suggested. Will this change the colors if I extra anneal?

pierces*designs · #4 2010-03-23, 5:08pm

I don't believe so. I am no expert and pretty much self taught. LOL But it works for me.

Kare TX · #5 2010-03-23, 7:27pm

I think your garage temp may be low.
Found this at ...
http://www.camglassblowing.co.uk/gproperties.htm

510°C (950F) - Temperature at which thermal stress can be introduced to Borosilicate glassware.
565°C (1049F) - Annealing temperature. When uniformly heated in controlled conditions, such as a kiln or oven thermal stress’s can be removed.

Alaska · #6 2010-03-23, 9:05pm

Yes, 1050 F is where you want to be. The annealing temperature can be as high as 1090 F to a low of 1030 F depending on thickness. The critical strain point temperature is around 950 F.

Most use 1050 which works well as a default value.

For a good review of annealing see chapter 8 in "Contemporary Lampworking"3rd edition by Bandhu Dunham. They also have a nice annealing chart on page 226 for boro.

Have fun with boro - it is most interesting.....

Kare TX · #7 2010-03-23, 10:00pm

Donna,
A couple of questions you asked and we didn't answer yet:
Crack on the focal - when you "weld" two pieces of boro you need a smooth connection. the seam line you can feel (your nail catches in the seam) when cool is not good with boro.

Also your question about color change- it really depends on what colors you are using. most the WYSIWYG (what you see is what you get) colors will stay the same. Any Amber purples may change on you since heat is what develops the color in them.

Glass Alchemy, North star and TAG all have good information on their sites that may help you

Donna T. · #8 2010-03-24, 4:48am

I annealed them at 1050 for about 2 hours (how long I worked) then dropped to 950 for an hour then ramped down. I thought that is what I read to do, is this wrong? My thought was when I dropped to 950 I could do soft glass the rest of the day or is it not good for the boro to sit at 950 for several hours after it's already been annealed at 1050? I didn't do any soft glass the day I made these beads.

Bunyip · #9 2010-03-24, 7:57am

Some Boro Greens & sparkle colors don't like to be encased, and one of the cracks looks like it may start there. There is also a viscosity difference between clear & colors which may contribute to cracking problems with certain dense colors. I've also noticed that I get similar cracking when I make boro mandrel beads on larger mandrels and with thick clear encasement - it seems like the mandrel may have been stealing heat from the bead, my footprint wasn't wide enough, or both.

And the weld is crucial. If your weld is undercut, cracking may be a problem.

davelovins · #10 2010-03-24, 8:10am

Hi Donna, I agree with Kare. When toy weld boro together, you have to get both pieces the same temp. This fuses the glass and they become one. As for the rough edges, I always reduce my flame to a very small pointy flame, and then smooth out the ridge all the way around. by reducing the flame, it makes it easier to do without melting the surrounding glass. Keep in mind that I am far from an expert, but this works for me. Hope this helps.

AutEvDesigns · #11 2010-03-24, 9:12am

Quote:

Originally Posted by Donna T.

If you are going to garage boro at 960 or so can you do boro first then turn down to 960 and work on soft glass the rest of the day?

I would say no. I don't know your process for annealing soft glass, but my guess is that you don't keep opening and closing the door after the annealing temperature, but let it cool slowly through the strain point. For the same reason, I wouldn't let the boro go through the annealing cycle, then drop it down to 970F and keep working. You want it to cool through the strain point, which is around 950F. Brent Graber would be the one I'd ask for sure.

Quote:

Originally Posted by Donna T.

Here are pictures of what I did this week. The two clear ones are fine but the bead and the focal both cracked. I used the same white in both of them which may be the problem or did the focal crack because I didn't put enough heat where the bead met the formed piece and where the punty was? I don't know what white it is as I was gifted all my rods except the frit.

If it was the white I sent you it was GA Sno White. Sometimes I've had cracking when I've encased it with Persimmon Strike and Clear if I put it in a fiber blanket instead of the kiln. I couldn't tell you for certain, but I think it may just be more sensitive to temperature change than other colors, so you'd want to make sure to get the whole bead orange again before putting it into the kiln and see if that helps.

Quote:

Originally Posted by Donna T.

I'm also having trouble rounding up the bead. Is my torch not hot enough? I'm on a Bobcat with one concentrator. One of my favorite things to do with soft glass is gravity but I'm having trouble getting boro to flow.

It depends on the concentrator, but with my one Devilbiss I also had trouble going from oval to round. Interestingly, I use the opposite technique as Debbie - I spin in one direction for soft glass, but when rounding boro, going back and forth does seem to help me; so, experiment and see what works for you. I can also tell you, since I got my second Devilbiss, working boro has been going more quickly because the additional oxygen helps the fuel to burn hotter.

AutEvDesigns · #12 2010-03-24, 9:14am

P.S. Very pretty beads!

ginkgoglass · #13 2010-03-24, 11:55am

There are a couple of threads on annealing boro and soft in the same session here somewhere, but I searched and can't find them.

The way I understand it, you can work boro, garaging at 1050, then ramp down to 950 and work soft glass.
Then run your normal annealing schedule for soft glass.

This is what I do:
Ramp Full to 1050
Hold 4 hours (or whatever time you are working boro)
Ramp Full to 1150 for an hour for striking (this can be anywhere from 1125 to 1250 depending on your kiln)
Ramp Full to 1050 for 1 hour (my pieces are rarely over 1/2 inch thickness)
Ramp at 60/hour to 950
Off (or do your soft glass schedule)

What you don't want to do is hold at 1250 for long periods of time, because this leads to phase separation.
http://glassalchemy.com/index.php/re...ase-separation

Some people don't strike in the kiln and just flame strike. If you are using an amber purple or other highly silvered glass for the beads above, you can increase your color by finishing your piece making sure you work it really nice and white hot, and look for the haze that burns off. You will see it disappear like a film that becomes clear. Then let it cool below the red glow (look at it under the table). You can even use a fan or blow on it to get the temp down faster. Then bring it back into the tip of the flame and slowly rotate the piece till you start to see the color develop. It is so cool the first time you see this happen!

Mr. Smiley · #14 2010-03-24, 1:19pm

What Lana said, but i just hold at 1080 while i work and it strikes my silver colors just fine... there's more than one way to skin a cat when it comes to striking, but the slow ramp down she outlines is crucial...

If you use white directly on the mandrel, if can cause cracks like that, but most often it's from putting them in the kiln too cool. Keep at it... your colors look great! You've gotten some great advise already...

Donna T. · #15 2010-03-25, 1:42pm

Thanks for all the good advise everyone. So I'm thinking maybe the white directly to the mandrel maybe some of it, probably not keeping it hot enough, and ramping down too soon. I will definitely keep trying, I was pretty happy with the colors I got -don't know if that's the colors I was supposed to get

Thanks again for all the help and ideas!