CraftWEB Hot Glass Talk  

Go Back   CraftWEB Hot Glass Talk > Hot Glass > General Hot Glass Discussion

Reply
 
Thread Tools Display Modes
  #1  
Old 07-07-2020, 12:10 PM
Josh Bernbaum Josh Bernbaum is offline
Registered User
 
Join Date: Feb 2009
Location: Brattleboro, VT
Posts: 706
Josh Bernbaum is on a distinguished road
Antimony in a batch

I've been using a bit of SbO3 in my phosphate melts lately, and wondering what is the typical percentage, either of the total batch weight or the oxide percentage, of antimony used for fining in a clear batch? I've been looking around in Schoales and Volf and haven't been able to find that exact info in their books. And the old European recipes I have notes on only used arsenic. A lot of it.. I have noticed better fining I think since using the Sb, but I'm not using much and maybe it could be more? Spreadsheet says I'm at a 0.41 oxide percentage right now.
Thanks
__________________
www.jmbglass.com
instagram.com/joshbernbaum_glass
Reply With Quote
  #2  
Old 07-07-2020, 01:53 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Scholes, Sam Scholes to be specific. Pronounced like Skoles.

I regularly add 75 grams of Antimony tri-oxide to 80 lbs of clear batch Josh. That, in conjunction with 100 grams of potassium nitrate. I prefer potassium over sodium since it contributes to the general luster of the glass while sodium does not. Arsenic is used in leaded glasses more commonly since the valence flip occurs in a different range.

If you increase the amount of it to around 2%, it becomes a glass that will reduce to a smoky gray in such a way that if you have done a clear threaded overlay from a different source, you will see a really nice subtle pattern in the glass. Pretty stuff but antimony is not cheap sadly.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #3  
Old 07-07-2020, 02:01 PM
Brian Bradshaw Brian Bradshaw is online now
Registered User
 
Join Date: Jun 2016
Location: Lakewood, CA
Posts: 13
Brian Bradshaw is on a distinguished road
Josh, don't know if this will help or not, but back in the day we were melting a opal in an invested pot furnace with the following formula with good results when fined out.
This is in pounds:
61 Sand (Oklahoma #1)
17 Soda
13 Pot Carb
11 Zinc
7 Tricalcium phospate
2 flurospar
50 gr. Antimony

Just my 2c...!
Reply With Quote
  #4  
Old 07-07-2020, 05:38 PM
Josh Bernbaum Josh Bernbaum is offline
Registered User
 
Join Date: Feb 2009
Location: Brattleboro, VT
Posts: 706
Josh Bernbaum is on a distinguished road
Thanks, I feel bad spelling his name wrong because it's just about my favorite book on the subject. I have a neighbor who spells his last name Schoales so that's prob the confusion. So I've been using more antimony than you, Pete, and Brian mention. My last few melts have been about 81g in 52 lbs. of batch. (If John C. reads this, grams and lbs. in the same sentence, it's gonna drive him nuts..) I've been using sodium nitrate because I have potash in there anyway and these days I'm into the lower viscosity that sodium provides.
Good to know I don't need any more Sb in there it sounds like.
__________________
www.jmbglass.com
instagram.com/joshbernbaum_glass

Last edited by Josh Bernbaum; 07-07-2020 at 05:41 PM.
Reply With Quote
  #5  
Old 07-07-2020, 06:19 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Indeed, I drive John nuts with my crossovers. It's the "C" to "F" that really gets him.

Good thing he's really retired. What a great friend to have had in life.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #6  
Old 07-07-2020, 06:58 PM
Art Freas Art Freas is offline
Registered User
 
Join Date: Aug 2014
Location: Washington
Posts: 684
Art Freas is on a distinguished road
Is this the Volf book? Chemical Approach to Glass

There seems to be three, Chemical Approach, Technical Glasses, and Mathematical Approach.
Reply With Quote
  #7  
Old 07-07-2020, 07:00 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Chemical approach is the book you want. Igneous books does sell it at about $200.00 per softbound. It won't get reprinted.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #8  
Old 07-07-2020, 07:57 PM
Art Freas Art Freas is offline
Registered User
 
Join Date: Aug 2014
Location: Washington
Posts: 684
Art Freas is on a distinguished road
Thanks much, on the way.
Reply With Quote
  #9  
Old 07-07-2020, 10:45 PM
Andrew Horch Andrew Horch is offline
Registered User
 
Join Date: Oct 2018
Location: Seattle WA
Posts: 8
Andrew Horch is on a distinguished road
When I tried ~1.5% antimony I had a problem with foaming. Is there a trick to reduce the foaming? Or, do you just not fill the pot and wait it out?
Reply With Quote
  #10  
Old 07-08-2020, 07:40 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
well, it does release oxygen much in the same way as manganese dioxide does. It never bothered me much. Just knock it down.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #11  
Old 07-09-2020, 08:49 PM
Hugh Jenkins Hugh Jenkins is offline
Registered User
 
Join Date: Sep 2006
Location: Honoka'a, HI
Posts: 1,007
Hugh Jenkins is on a distinguished road
1.5% antimony Pentoxide is off the charts. Less than 0.1 % will give sufficient fining if oxidizer is present and melting done correctly. Charging too hot releases a lot of the oxygen too early. Charging in the 2100 to 2150 range and then doing a heat up of the complete charge, saves the oxygen until later in the heat up. Then it will froth but should not boil over. Antimony is a close chemical relative of arsenic and should be handled as a toxic agent. Using way more than you need is wasteful and dangerous. Antimony also absorbs oxygen in the cooling down phase of melting (the "squeeze") and is counter productive to Manganese and phosphate.
__________________
Aloha, Hugh
Reply With Quote
  #12  
Old 07-10-2020, 07:43 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Antimony at those percentages causes color. At higher percents it goes dense opaque as does an arsenate. They flip valences at different temperatures. It is indeed toxic. a gram a pound is abut right for fining.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #13  
Old 07-10-2020, 10:21 AM
John Croucher's Avatar
John Croucher John Croucher is offline
Registered User
 
Join Date: Jul 2003
Posts: 66
John Croucher is on a distinguished road
A gram a pound. I like it
Reply With Quote
  #14  
Old 07-10-2020, 01:21 PM
Hugh Jenkins Hugh Jenkins is offline
Registered User
 
Join Date: Sep 2006
Location: Honoka'a, HI
Posts: 1,007
Hugh Jenkins is on a distinguished road
Measuring batch in grams would be crazy, and measuring colorants or small additives in ounces does not make sense either. Fifty years of weighing batch on a pound spring scale and less than pound on a scientific gram scale is a perfect combination.
Vegetables I can handle either way.
__________________
Aloha, Hugh
Reply With Quote
  #15  
Old 07-10-2020, 03:03 PM
John Croucher's Avatar
John Croucher John Croucher is offline
Registered User
 
Join Date: Jul 2003
Posts: 66
John Croucher is on a distinguished road
In New Zealand we occasionally revert to the old traditional Sumerian weights and measures.
https://www.britishmuseum.org/collec...mage/327059001

The correct amount of Sb2O3 would then be 16.5 light grains to 1 light mina of batch.
Reply With Quote
  #16  
Old 07-10-2020, 03:14 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Quote:
Originally Posted by John Croucher View Post
A gram a pound. I like it
***
It's in the interest of international cooperation. What do you think we are , Shipping Clerks?

At least the ratio is pretty good.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #17  
Old 07-10-2020, 03:18 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Quote:
Originally Posted by Hugh Jenkins View Post
Measuring batch in grams would be crazy, and measuring colorants or small additives in ounces does not make sense either. Fifty years of weighing batch on a pound spring scale and less than pound on a scientific gram scale is a perfect combination.
Vegetables I can handle either way.
****
I do all of my big items on the digital scale. I run two next to each other as a reality check. I suppose I could switch it over to grams instead of pounds but I'm old and difficult. I measure both my potassium nitrate and my antimony on a gram scale. It's not hard. I do all my colorants on that scale as well. I always find it interesting when I use a big digital scale for measurements how you can watch the digital readout and you can add stuff to the mix bucket. You pour a bit, it doesn't change. You pour a bit more, it does change. I don't skimp on my scales but that's reality. I sell crucibles based on capacity in pounds, not KG's. I sell color rod in KG's. I sell eggs in dollars and dozens. I sleep OK at night.

I'll stick to what I do.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #18  
Old 07-10-2020, 03:23 PM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Quote:
Originally Posted by Hugh Jenkins View Post
Measuring batch in grams would be crazy, and measuring colorants or small additives in ounces does not make sense either. Fifty years of weighing batch on a pound spring scale and less than pound on a scientific gram scale is a perfect combination.
Vegetables I can handle either way.
***
Now spring scales I do consider worthless.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #19  
Old 07-10-2020, 04:12 PM
John Croucher's Avatar
John Croucher John Croucher is offline
Registered User
 
Join Date: Jul 2003
Posts: 66
John Croucher is on a distinguished road
Quote:
Originally Posted by Pete VanderLaan View Post
***
It's in the interest of international cooperation. What do you think we are , Shipping Clerks?

At least the ratio is pretty good.
That is what I like about the ratio! -1 gram per pound is easier to remember than 0.25% -which is about the perfect amount!
Reply With Quote
  #20  
Old 07-11-2020, 07:55 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
Quote:
Originally Posted by John Croucher View Post
That is what I like about the ratio! -1 gram per pound is easier to remember than 0.25% -which is about the perfect amount!
****
Well, I do get defensive. I recall a certain someone who always used to give me a hard time about my intimate mixes of systems of measurement. I wouldn't want to mention any names.

The only way I can see spring scales working is if you are just weighing out SP87 batch which is already mixed to its correct values. I would not expect consistent results at all if I was trying to measure individual components each time. Good scales are your friend. Two good scales is even better.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #21  
Old 07-11-2020, 10:36 AM
Randy Kaltenbach's Avatar
Randy Kaltenbach Randy Kaltenbach is offline
Registered DancingChicken
 
Join Date: Aug 2003
Location: Calgary, Canada
Posts: 996
Randy Kaltenbach is on a distinguished road
Quote:
Originally Posted by Pete VanderLaan View Post
intimate mixes of systems of measurement
Hehehe. There's a phrase I just couldn't dream up
Reply With Quote
  #22  
Old 07-11-2020, 10:39 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,057
Pete VanderLaan is on a distinguished road
think how gold gets measured.

Dwts or pennyweights.
__________________
Where are we going and why am I in this basket?
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 05:23 PM.


All published comments within these message boards are the opinions of its contributor and does not represent
the opinion(s) of the owner(s) of this website. Please see the Terms of Use file for more details.

Books to Help Artists Avoid Online Scams: Top 10 Email Scams | Social Media Scams

Powered by vBulletin® Version 3.7.2
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
CraftWEB.com. Opportunity Network. 2008. All Rights Reserved.