By StickStuff - 6/20/2018 6:06:36 PM
I've recently purchased this silicone and a pump. I've watched your videos and admit that I'm new to all this.
But does this stuff go off? It seems VERY thick.
I mixed to 10% by weight, stirred slowly to avoid bubbles and trickled from the mixing cup to a wide-bottomed container within my vacuum chamber. This seemed to create more bubbles that I already had.
I turned on the pump and sure enough everything expanded very quickly... but it NEVER collapsed. Several minutes went by and I gave up.
I trickled over the pattern and could see loads of bubbles. It took over 5 minutes to trickle less than 100g of silicone. Is it always this slow and resistant to movement?
I placed the pattern in the vacuum chamber.
Quick expansion of bubble... never collapsed.
Does this stuff go off? Am I missing a step? I have far too many bubbles setting within the silicone.
Here's a video of the whole affair if it helps : https://youtu.be/JcAs4bQkRGc
I sped the whole thing up by 20x as it's so slow.
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By Warren (Staff) - 6/21/2018 10:48:32 AM
I would rule out a problem with the silicone itself as long as the silicone does cure properly. Even if it has for some reason thickened, at full vacuum, I would still expect the bubbles to self collapse fairly quickly.
So it sounds like the degassing system is not achieving full vacuum, bet it a leak somewhere in the system or the pump not achieving full vacuum. A bit of systematic checking should help determine where the issue lies.
Where is the gauge located? On the chamber is ideal as it gives a more accurate representation of the chambers vac level. If it is near the pump, it is possible that a small leak between the gauge and the chamber would not be reflected properly on the pump. You can shut off different sections of your system to see where there might be any leaks.
Check the hose fits fully onto the barb and the fitting is tight into the pump. Also check the level of the oil on the pump. The pump does not consume oil in the same way some other types do, so with relatively little use you have had from the pump, I would expect there should be no noticeable loss of oil from when you initially filled it with oil when you got it.
If you are still struggling to get full vacuum and it looks like the pump isn't getting there, then we would happily look at and test the pump for you to ensure all is working as it should and if necessary replace it in the unlikely event it is defective.
Hopefully it is something fairly simple to sort and you can get the leak free full vac you need.
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