You raise a good point
@Caligula in that you should never trust anyone from reddit on their word. Reading through the thread has given me doubts as well, I have an ebay container and would very much like to try and ruin some wax.
I took bout .2 of gold (orangeish) clear shatter piece and pressed it out flat as I could in the container so if it bleeds through should definitely be able to see it. Does anyone have any other ideas on how to speed up the leaching process? Think I'm just going to leave this in here for a week and then check again see if anything happened. Not very scientific but best I can do.
Another test I saw was someone weighed their container empty, then filled it whth Limonene which is a terpene. Not sure how long or whatever, they then poured out the Limonene and re-weighed the container. I don't recall If it got heavier or lighter but I do recall they said it's weight changed showing some interaction.
As far as the pinch test goes my understanding and knowledge from some material engineering and injection molding background leads me to go with this understanding of it. A polymer is essentially just the same structure repeated over and over, in this case it would be a Siloxane.
http://en.wikipedia.org/wiki/Siloxane
At the time of manufacturing the blank or raw material the factory has the option to put in certain things to act as a filler to allow the material to go farther. Now when I was making propellers this was killer because we could ask for certain highly rigid fillers, this would allow the same propeller design to withstand much more force and could be used in a different application than the original molded design.
What this means and what we are talking about when it comes to these containers is that some manufactures will just buy the cheap material and inject it into containers. I assume that as you bend the container it somehow is showing you the impurities due to the fact that the silicone is more clear as you bend it but the impurity does not act the same.
The test originally came from a NY times article which was talking about silicone molds for food.
http://www.nytimes.com/2007/01/10/dining/10sili.html?pagewanted=all&_r=0
That was linked in the OP of this thread.
But I wanted to get more info than just my basic understanding and did some more digging.
http://hollandaptblog.com/2013/12/0...m-cured-silicone-tubing-whats-the-difference/
That article does a good job of explaining platinum VS not.
Then, since they seem to be the only company who wants to talk, I called Oil-Slick. I first spoke to a receptionist and we spoke a little and her understanding and explanation was unsatisfactory so she took my info and roughly a half hour later I was called back by a gentleman who's name I've forgotten but he gladly answered all my questions all the info from this point on was stuff he helped inform me of.
First off; The pinch test is valid for the exact reason I stated above. As silicone is bent or stretched highly it begins to become more and more opaque however the same is not true for the filler molecules so when you see any new coloration appear during the pinch test that is an impurity you are seeing.
Second; Oil-Slick only obtains the most pure blank material they can, and the then soak it in acetone (or another aggressive solvent) to remove any residual fillers and use Spectroscopy to measure the purity of the blank material before even injecting it. The two big common fillers that get used by manufacturers that we need to worry about are Formaldehyde and Disophenol both of which you can easily research their toxicity.
The reason I decided to replace my original cheap silicone container was because it was starting to form a white crusty powder on the bottom of it, and it was obviously separating from itself. Turns out there is actually a term for this and it is called "bloom" it is caused by a filler getting pulled out of the silicone matrix causing a void in which silicone oxide begins to form.
Also apparently food grade silicone is not good enough for Germany as they require LFGB quality silicone which is strict on no Formaldehyde and Disophenol fillers.
http://www.theodmgroup.com/2013/08/20/testing-standards-for-silicone-products/
The gentleman at Oil-Slick also told me that if any of you would like to have this same discussion I did with him about this yourself then feel free to give them a jingle. Their phone # is clearly listed on their website.
So in closing, yes as far as I can find and inform myself the end user consumer, the pinch test is valid and I will be using it from now on.
