Quote from kirkrhino on May 13, 2014, 14:24
What is the blowing on the PDMS about? Perhaps the condensation from your breath is ending up on the surface adding moisture to
the mix? I have heard some jewelers use the "oxygen" side from their torch on the PDMS to disperse bubbles, but would not suggest blowing on it.
Keep this in mind: At the (low) safe temps Mike mentions, the bubbles are never a concern., Just pop in oven, (make sure it's level) and don't touch it until it's finished.
Otherwise beginning to wonder if perhaps maybe your PDMS has gone bad? Is there an expiration date or something? Tim I think we are all as baffled as you are at this point.
There are at least 30+ others out there an not a single mention of such a thing by anyone else. Have never experienced such a thing myself.
If there is anyone else having any similar issues, please let us know?
Have no idea really what is going on. The glass is pyrex, (borosilicate)..can easily handle low or high temps in the oven. but again have had no issues myself or heard complaints @ higher ones. The PDMS by dow is rated to 300. But yes, please try @175. Bubbles have time to disperse on their own at that temp.
If there was just one other person experiencing the same problem maybe we would be onto something, but I have every confidence it has nothing whatsoever to do with the VAT if that's what you are thinking?
But if that's your conclusion, please will be happy to take it back immediately.., can't go on like this. : ) Too painful to see you having no success! Have exhausted all possible ways to assist.
Quote from Metalcaster on May 13, 2014, 14:35
What if his oven is not accurately calibrated... It could be hitting temperatures above 350 oF and combine that with the amount of time that it is in the oven, that would certainly spell disaster!
I use a lot of RTV rubber similar to the pdms ... they don't recommend going over 200 oF .
At 150 oF it cures in 2 hrs or less. At 200 oF it should be done in less time.( about 1 hr)
If you are at 300... you should be done in 10 minutes or less... perhaps by using high temperature, you need to reduce the time in the oven to 10 minutes... Just a thought.... or, just do it at 150 oF for 2 hrs... Better safe then sorry!
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