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Re: Image bleeding as mug cools down
Posted: 27 May 2011, 16:00
by Paul
John G;23723 wrote:
I used to dunk but as Paul said, they ping a little - and that cannot be good for the mug.
and it can not be good for the person who got hot tea in it

if fall in bits in somone elese hands

Re: Image bleeding as mug cools down
Posted: 27 May 2011, 16:05
by Daveb
John G;23723 wrote:Where your mugs from?
I don't dunk - I put a fan on the work bench set to cool and just place the mug in front of it after taking the paper off. By the time the next mug is ready the first ones cold.
I used to dunk but as Paul said, they ping a little - and that cannot be good for the mug.
John,
The mugs are my first box. I got them off eBay, from Coralgraph. I had no complaints about them to be honest, but I want to try the RN coated ones off BMS next.
I wondered whether minor variations in the mugs could have been at the back of my problems, and there seems to be an improvement now that I adjust the pressure slightly if necessary to suit the individual mug.
I'm still waiting for someone to confirm or deny that minor variations in mug dimensions are normal.
Dave
Re: Image bleeding as mug cools down
Posted: 27 May 2011, 16:07
by NASH
Paul;23725 wrote:and it can not be good for the person who got hot tea in it

if fall in bits in somone elese hands

I`m not saying this could not happen but i`ve been doing mug for 3 years and i`ve not had one back from anyone yet.
Maybe i`m just one of those lucky ones
Re: Image bleeding as mug cools down
Posted: 27 May 2011, 16:14
by NASH
I'm still waiting for someone to confirm or deny that minor variations in mug dimensions are normal.
Dave[/QUOTE]
The one i use from BMS always been sent to the same pressure, but i do preheat the mug on a radiator in the winter months and in the summer place them on my film processor to heat the base up
Re: Image bleeding as mug cools down
Posted: 27 May 2011, 16:16
by Paul
Nash. I am saying IF you got that ping noize then you may have a complain. not only coz you dunk them. I did it too.
Dave. I had a mugs from coralgraph, BMS, subli-nation and some other from ebay. they all ping

Re: Image bleeding as mug cools down
Posted: 27 May 2011, 17:31
by swimwivsquid
I have always dunked my mugs in warm water and haven't had a problem. I would think that its better for the mug to break at that stage than in someones hand full of coffee. I would think its a defect in the mug or using too cold water.
Re: Image bleeding as mug cools down
Posted: 27 May 2011, 17:55
by Paul
same here. Mate asked me to do some mugs for hos company. I dunked them as me too preffered that they brake before they live my room

Re: Image bleeding as mug cools down
Posted: 31 May 2011, 23:32
by mrs maggot
i had one bleed at the weekend, i had a good look at it, and then noticed the teflon sheet i have between the press and the mug had a crease in it - sorted.
i dunk, but will be trying the fan method, as i like the "cool idea"
Re: Image bleeding as mug cools down
Posted: 01 Jun 2011, 09:22
by Daveb
mrs maggot;23965 wrote:i had one bleed at the weekend, i had a good look at it, and then noticed the teflon sheet i have between the press and the mug had a crease in it - sorted.
i dunk, but will be trying the fan method, as i like the "cool idea"
Mrs Maggot (really?), Interesting use of a teflon sheet. Do you tape it over the sublim sheet, or attach it in some way to the heat blanket? Dave
Re: Image bleeding as mug cools down
Posted: 01 Jun 2011, 09:38
by Daveb
Paul;23730 wrote:Nash. I am saying IF you got that ping noize then you may have a complain. not only coz you dunk them. I did it too.
Dave. I had a mugs from coralgraph, BMS, subli-nation and some other from ebay. they all ping

Paul,
My only 2 experiences with dunking were, first one, after removing sheets, put mug in fairly hot water (say 50C) and it cracked - it didn't just ping, you could see the crack afterwards. Second one, without removing sheets, made a hissing noise, didn't crack or ping, but the sublim sheet stuck to the mug - maybe I dunked too long 20 secs? In both cases, the mug was completely submersed.
To be honest, unless it is an integral part of the process, I would rather skip the dunking - anybody out there a confirmed non-dunker?
Wiith dunking the amount of fast heat drop, from +180C straight into water between maybe 20C to 50C, is a large drop. The sudden temperature change causes the fast contraction that causes the pinging and even cracking. In normal use, boiling water is only 100C so you just don't get that same amount of change.
As I understand it, the idea behind dunking is to stop any further sublimation by dropping the mug temp down below the temp required for sublimation to happen. Maybe if I set my press to a lower temperature, it would cool naturally below the sublim temperature just by standing on a tray? Does anyone know the sublim temperature, and/or a reliable way of checking the press temperature? According to my settings, I am pressing at 185C - I'm thinking I will drop the temperature when I do my next batch, maybe in 5C steps, down to say 170C.
Dave