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.

My first suspicion is that your vac chamber doesn't actually get to full vacuum. I know you say it's air tight, but how do you know? Does it have a vacuum gauge? Can you pull a vacuum, switch the pump off, and come back a few hours later to find it hasn't leaked at all? 

To me, it looks like the silicone want to collapse but it's only at about 90% vacuum. Everything happens in that last 10%, so if it isn't actually getting there then it won't collapse.

Otherwise, what temperature is it where you are at the moment? If it is cold, the material will be significantly thicker. I can't really see a whole lot wrong with your silicone, although I dont know EC's silicone at all. If it cures though, it isn't expired. Viscosity really shouldn't prevent a material from degassing, it may just take longer.

Hi Warren,
Thanks for the prompt reply.
Are you suggesting your pump is faulty? This is it’s first outing having just purchased it from you #145685
The gauge isn’t much good I admit, but it does max out. The chamber is home made but is completely air tight. How do I know? Because I can place it under vacuum pressure, shut off the valves and the pumps, and the pressure remains constant.
This leaves us with two things, the pump or the silicone.
Watching your video again last night I thought, “Mine doesn’t mix as easily as that. Mine doesn’t flow like that.”
Mine is thick. I don’t have a curing problem – if anything the opposite. It stiffens VERY quickly.
I measure carefully on the scales I bought from you. I mix well and I vacuum quickly. I see everything but NOT the collapse. Did you watch the video.
At the moment I’m a few hundred quid out of pocket and feeling something is VERY wrong somewhere...
Thanks

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.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant