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Mark Dolan
01-16-2012, 12:21 PM
My gold adventurine is dulling out and ending up as brownish spots rather brilliant gold flecks. I suspect I'm either running my glory hole too hot or my air mix is too lean and I'm reducing a bit. In any event, Tonight I am going to readjust my settings and because I'm new to GH maintenance, I want to make sure my procedure for doing so is sound.

First, my setup includes an air pressure switch set to around 2.75 WC, a pyronics air butterfly valve, and a needle value to control gas input. I also have installed a high/low gas pressure switch and all safety switches are wired to an Eclipse Manual shutoff switch.

After reading past threads on this topic, some people dampen down the air coming out of the blower at GH startup. Because of my above-mentioned setup, I don't feel the need to monkey with the blower. Here is what I plan to do:

1.) Adjust the air butterfly valve to 1/4 way open
2.) open the gas needle valve slightly
3.) light glory hole and observe flame
4.) adjust either air or gas as needed to achieve a neutral blue flame.

I think it is just this simple, but maybe I'm missing something. Any comments from you vets would be appreciated.

Mike Hanson
01-16-2012, 03:30 PM
Are you gathering over the aventurine or are you working it on the outside?
It won't look too good unless it is covered in clear. Also if you are working it too long un-encased in a reduction atmosphere you can burn it causing it to turn brown, sometimes with a dark halo.
I always adjust my GH after it gets hot. I have a bench mark that I start with and depending on what I am doing , meaning how hot I want to work that day, I adjust accordingly. I look from the side at the front opening and adjust it so there is no (maybe a little) flame coming out the door for a nice neutral flame.
I don't really look at the flame coming off of the burner as it is hard to see as the GH gets to its working temp.
Start up is different for each GH design, depends on what kind of burner and blower you have, there is NO set way for all GH's. You kind of just have to figure these things out as you put more time in with your own equipment. It will come to you as long as you are paying attention.

Mark Dolan
01-17-2012, 09:33 AM
Thanks for the reply Mike. I am working it on the outside. I adjusted my GH last night based on the procedure I described earlier and it seemed to help wih the adventurine quite a bit. I will however try encasing it with clear as you suggest. I have noticed that the longer I work it unencased, the less brilliant the adventurine becomes. Good advice Mike. Thanks again.

Joe Deanda
01-20-2012, 11:38 PM
Also that stuff reacts with most opaque colors, gets a black halo around the chips. Enamel white yellow and red come to mind. Dont get it to hot and always case with clear.

Steve Stadelman
01-21-2012, 12:28 AM
If your air mix is lean you are oxidizing. If it is rich you are in reduction. Just saying.

Pete VanderLaan
01-21-2012, 04:49 AM
Also that stuff reacts with most opaque colors, gets a black halo around the chips. Enamel white yellow and red come to mind. Dont get it to hot and always case with clear.
*************
The black is lead. Too hot, Too rich. Too long. keep it out of the direct burner until it's cased. Use the radiant part of the gloryhole.

Enamel whites have lead in them. Reds do not and cannot or they discolor. Put them next to each other and the lead will wreck the cad/sel color.

David Patchen
01-21-2012, 01:20 PM
I learned something interesting yesterday--when I make yellow veiled cane (over an enamel white core) and make it into murrine, I often get a grey haze on the bottom of the piece. I've suspected that this is the yellow running on the surface and turning grey where it reacts with the white. I've found it unavoidable when using yellow and white veiled cane in murrine.

However, I did a piece yesterday where I used citron over enamel white veiled cane in the murrine and I didn't see any greying whatsoever. While citron is a bit bright and green-tinted to my taste, it seems like a great option to avoid the greying I get with yellow and white. (It was a commission that required the citron).

What's the difference between Gaffer citron and yellow that would make the latter react w/white and the former not?

Kenny Pieper
01-21-2012, 03:31 PM
David what if you put a strip gather between the colors to protect the interaction from happening. I have to do this with between my duro white and carbon amber. The carbon in the amber turns the lead in the white black if they come in contact with each other. I use this in cane sometimes by making the clear layer very thin and as the color stretches thinner and thinner in twisty cane it starts to turn the color a bit brown and creates sort of an worm antiquity look.

Its probably the surfer in the cadmium sulfide reacting with the white

David Patchen
01-21-2012, 04:20 PM
Hey Kenny, I do exactly the same thing. I always put a strip between the white enamel center and whatever color I'm making veiled cane out of to prevent this and to give some added dimension to the cane.

But if after I make the cane, I then incorporate it into murrine and stretch it again and the distance between the inner white and color gets smaller and smaller as everything is stretched thinner. When working w/a color I know reacts poorly w/the white (like the yellow, reds and oranges) I always make my strip layer thicker. I guess if I was really freaked out by this I'd stuff a color cup to get the color really far from the center, but it's not worth the effort. They greying isn't a super-bad problem, but I was surprised there was absolutely none of this effect w/the citron.

Here's an example of the greying I"m referring to toward the bottom of this piece. Not a huge deal, but noticeable.
http://www.davidpatchen.com/assets/images/escape/gallery/images/65.jpg

Kenny Pieper
01-21-2012, 04:38 PM
Wow nice work!

Travis Frink
01-21-2012, 05:09 PM
Dave
Is the discoloration on the surface? Or within the cane itself? Hard to tell in the pic on my screen. I can see that it is really nice work though:)

David Patchen
01-21-2012, 06:17 PM
Thanks, I try :) The discoloration seems to be on the surface of the murrine which is underneath 2-3 gathers. I think I could solve this problem by picking up the murrine, melting it smooth and closing it, then making a blank out of it and boxing it. Once cold I could sand away the surface where the reaction is happening, then bring it back up in a kiln, put it back on the pipe for a quick fire polish, then begin gathering. This all seemed like a pain in the ass. Instead, I'll use citron and avoid the entire mess.

The piece that taught me this is still in the annealer, but it is a 32" tall version similar to the piece I linked to above. We sweated a little.

Eben Horton
01-21-2012, 09:05 PM
what you view as discoloration or a possible flaw is what will make the piece unique. ;)

David Patchen
01-21-2012, 09:15 PM
That's it--I'm doubling the price!

Pete VanderLaan
01-22-2012, 05:53 AM
While you're at it sell the cracked ones as kinetic art.

Travis Frink
01-22-2012, 06:27 AM
While you're at it sell the cracked ones as kinetic art.

It's not really a popular time to be professing capitalism

Rich Samuel
01-22-2012, 01:35 PM
what you view as discoloration or a possible flaw is what will make the piece unique. ;)

Or, as they say in Redmond, "It's not a bug; it's a feature!." :D

David Patchen
01-23-2012, 09:13 PM
Here's the one w/citron in the murrine that motivated my post. The citron stayed bright and didn't discolor. Kinda bummed I'll have to cut the price now per Eben's point ;) 31" big. Client wanted a wider diameter to the lip on it--don't blame me.

Rollin Karg
01-24-2012, 04:19 AM
Nice work David.

Art Ciccotti
02-08-2012, 12:48 PM
I noticed that gold adventurine was discussed. I have a question about blue adventurine. I use Spruce Pine Batch. I have tried the blue adv. but my pieces have cracked. Is there some way to use the blue adv. like if its used as 1/4"cane. Does anyone have experience with this particular glass? Thank you for the time. This is a not so important question but why does it only come in chunks and not bar form?
Art Ciccotti

Tom Fuhrman
02-08-2012, 01:04 PM
Art: don't feel like the "lone ranger". I've had the same experience with that stuff, but great results with the green which I know are entirely different "animals".

David Hopman
02-08-2012, 02:57 PM
I noticed that gold adventurine was discussed. I have a question about blue adventurine. I use Spruce Pine Batch. I have tried the blue adv. but my pieces have cracked. Is there some way to use the blue adv. like if its used as 1/4"cane. Does anyone have experience with this particular glass? Thank you for the time. This is a not so important question but why does it only come in chunks and not bar form?
Art Ciccotti

From what I heard they have to cool it in the pot and then break it out.

Pete VanderLaan
02-08-2012, 03:49 PM
You are correct. The aventurine structure forms at about 1700F. If heated it goes back to a solution.

Traditionally there are two types of aventurine only- chrome and copper, copper being far more difficult to form. There are products adding mica to glass which sparkles and they call it aventurine. It may be that cobalt is being added to the chrome stuff to get a blue since that should work. It's a very refractory glass and highly intolerant of expansion mismatch.