CraftWEB Hot Glass Talk  

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

Reply
 
Thread Tools Display Modes
  #1  
Old 09-04-2018, 07:23 AM
Josh Bernbaum Josh Bernbaum is online now
Registered User
 
Join Date: Feb 2009
Location: Brattleboro, VT
Posts: 574
Josh Bernbaum is on a distinguished road
Bringing electric furnace up to charging temp

I've never set a program on my Watlow 981 controller for bringing the temp up before charging, I live next door to the shop and I've always just set my alarm a bit early that morning and turn up manually so then I can put in the first scoop about 2 hrs. later. But I'm getting old and I like my sleep, and since I have this programmable controller figured I'd try a program to bring it up for the first time in 8 years. Also like the idea of having time to let it "soak" at that higher temp for at least an hour for quicker results with the first charge at least. Question is about power usage I suppose, and limiting "wear and tear" on the now extinct 981 controller. Would it be more cost-effective to have it ramp up slowly overnight, not letting the % output get too high, or would it be recommended to let it to shoot up as fast as possible a few hours before I wake up? I think the answer would be the former, but curious about others experience with this. Thanks
__________________
www.jmbglass.com
instagram.com/joshbernbaum_glass

Last edited by Josh Bernbaum; 09-04-2018 at 07:35 AM.
Reply With Quote
  #2  
Old 09-04-2018, 08:24 AM
Eben Horton Eben Horton is offline
Registered User
 
Join Date: Apr 2002
Location: Wakefield, RI
Posts: 4,355
Eben Horton is on a distinguished road
Mine is gas but I usually leave my studio at 6 pm so I have a program that has it crash down to 1800 and hold until 5 am. Then ramp over 3 hours to 2300 and a hold at 2300. Having it soak a while before you charge makes a big difference in rebound speeds.

I generally never have my furnace go to 100% burner output if I can avoid it. Thatís how things crack.
__________________
<eben epoiese>
Reply With Quote
  #3  
Old 09-04-2018, 09:23 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 20,420
Pete VanderLaan is on a distinguished road
If you look at ramp rates on AZS, it is consistent to not go faster than 120 degrees an hour even if you are already at 2100F. What makes that a problem in AZS is that the very act of adding batch to the furnace vastly exceeds that parameter. So, the AZS cracks and is viewed as normal. AZS is certainly fussier than alumina pots but going slow makes pots last longer. Slow always makes refractories happier. Eben's point about the furnace being saturated with heat when you start your charges is a good one.

So, Josh, you're getting old now? Poor baby.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #4  
Old 09-04-2018, 10:29 AM
John Riepma John Riepma is online now
Registered User
 
Join Date: Apr 2003
Location: Grand Haven, MI
Posts: 481
John Riepma is on a distinguished road
Josh, I use a program to ramp mine up and I usually start that program at 1-2 pm, since most days I'm done working by then. I work at 2060 and have the program ramp up to 2075 in one minute, just to make sure that the controller has entered the program. Then it hold at 2075 for 12 hours and ramps to my charging temp over a 3 hour period. By 7 am the following day it's up to temp and ready for me to charge. I have another program to hold at the elevated temp for 8 hours and then go down to 1975 over an hour. I did this because I live 25 miles from the studio and can't run back and forth to babysit.

I should also mention that this is done with a Watlow EZ-Zone controller that replaced my 981. I sued to do the same thing with the 981 but one day noticed when I started the "cook" program the it had decided to skip that step and drop to 1975 immediately. I hear from several people that the 981's are starting to fail on a fairly regular basis so I don't think that this problem was unique to my controller. I have the controller programmed to use the EZ-1 and EZ-2 buttons to start both of those charging programs.

This is just my 2 cents worth assuming that you are planning on using the Watlow that you have or replacing it with the EZ-Zone. I know that there is plenty of dislike for Watlow on this board and there will undoubtedly be ample commentary on how another controller is a better choice. I'm just relating my experience, not endorsing any particular brand. And I can tell you that using a controller for this will save you a lot of time.
Reply With Quote
  #5  
Old 09-04-2018, 10:36 AM
Josh Bernbaum Josh Bernbaum is online now
Registered User
 
Join Date: Feb 2009
Location: Brattleboro, VT
Posts: 574
Josh Bernbaum is on a distinguished road
Well, I feel old anyway. And my 8 year old thinks I'm old..

I've always only ever turned up to charge temps as fast as possible with the alumina pots in there. Even after a power failure that hasn't taken the temp too low. I can't speak for AZS. So I've either been lucky with blasting on 100% output, or all the 22" pots I've had in my moly furnace so far (or the 14-16" in my gas furnace) can just take it, or a combination of both. But it makes sense that going slower, if time allows, would be easier on most if not all refractories. And maybe the moly heaters too? Since I feel like I've been doing okay with wear and tear on pots (I'm knocking on wood really loudly right now..), my thinking has to do more with saving on the amount of wattage drawn. I'm curious, Eben, if you know for certain that you're seeing a net savings on gas use if you drop down to 1800 before going all the way up to 2300. I've been wondering (and not testing yet which I could be) for a while now if turning down at night is more cost effective than just leaving at working temp. Yes, it must be less fuel/elec. to maintain a lower setpoint, but then one has to add the extra fuel it would take to reclaim that each morning or whenever temp has to go back up again. (I suppose esp. if that means coming up at 100% output) So then that brings me back to what I'm curious about in my first post here.

John, I like hearing that you've been able to replace the 981 with an EZ Zone. I run one of those on my gas unit. It's always in the back of my mind that I don't have a replacement controller "on the shelf" for that inevitable that will prob. come at the worst time possible.
__________________
www.jmbglass.com
instagram.com/joshbernbaum_glass
Reply With Quote
  #6  
Old 09-04-2018, 11:27 AM
Pete VanderLaan's Avatar
Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
 
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 20,420
Pete VanderLaan is on a distinguished road
I do tend to think you'll have less bubbles in glass that has been turned down to around 1900F at night. That would vary based on the glass viscosity. Crucibles will do better left at a constant temperature as long as it's not super hot and again, that would be based in viscosity as well. Keep in mind that no one glass is particularly more corrosive than any other but the viscosity of the glass is the issue getting into interstitial spaces. That being said, there are some combos of chemicals put in a glass that tend to cause more trouble than others. Boron and barium together come to mind. I'm rather clueless about why that would be the case. Barium is really a two edged sword.

At one point my son asked me what it was like to be really old. That was almost 20 years ago. Back then, I thought it was funny. Today? It just sucks.
__________________
Where are we going and why am I in this basket?
Reply With Quote
  #7  
Old 09-04-2018, 01:43 PM
Eben Horton Eben Horton is offline
Registered User
 
Join Date: Apr 2002
Location: Wakefield, RI
Posts: 4,355
Eben Horton is on a distinguished road
Josh, I turn it down every night to 1800. I could probably go lower, but 1800 is a good compromise I think. I know for sure I save money. And I know double for sure Iím saving money now with my variable speed blower just whispering along at 1800.
__________________
<eben epoiese>
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 04:19 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 - 2018, Jelsoft Enterprises Ltd.
© CraftWEB.com. Opportunity Network. 2008. All Rights Reserved.