Finally, a Vacuum!

Yes indeed; the lovely new vacuum pump I bought from Unicorn Tools seems to be working beautifully. I messed around with it for the entirety of Friday and managed to mostly degas 200mL of silicone.

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Mostly. I was having some problems with this. For one thing, I had to tinker with the levels of oil inside the vacuum pump. The oil expands when it warms up so I have to be careful how much I fill it. I can’t just dump the oil in until it hits the “FULL” line because when I turn it on and it heats up, it will sputter and spit out the exhaust port. Yuck!

The other problem I had was that there were still bubbles in the silicone after 15mins of degassing. I had already been tinkering with the silicone for awhile and I was getting dangerously close to the end of its working time. If I didn’t just bite the bullet and use it, I’d have a blob of semi-solidified garbage and the material would be wasted. So I just crossed my fingers and poured it into the moulding box.

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I don’t think you can see the air bubbles in the silicone from this shot. I was having problems taking a photo of a completely transparent object encased in a completely transparent layer of silicone. It’s a pain in the butt taking pics of a see-through object! The camera does not want to focus on it.

The green and white goo under the plastic square I’m moulding is just modelling clay. It’s there to keep the square stuck to the bottom so it won’t float and also to keep the silicone from sneaking underneath it. As you can see, I missed a spot. Oh well. That just means I’ll have to trim the silicone “flash” (extra bits of mould material that sneaked where I didn’t want it to go) when I take the mould out of the box.

Hopefully when I get to the workshop today, I will find that the air bubbles have escaped the silicone and I will have a nice solid, smooth mould to work with. Everybody cross your fingers!

I have a couple ideas as to why the silicone misbehaved. It could be that it was too old. It was very chunky and blobby when I took it out of its container. There’s also the possibility that the vacuum chamber was simply too big for this tiny amount of material. I’m going to try putting some extra stuff (plaster brick or somesuch) in the pot with the liquid I’m degassing to see if it will pull the air out faster and more efficiently. I’m sure I’ll figure it out. It’s just a little frustrating.

Before I run off to work, here’s a video of the new pump at work.

Author: Ethan Kincaid

Ethan Kincaid was born in 1985 in Brockville, a sleepy little town on the St. Lawrence River. He graduated from Carleton University in Ottawa with a degree in Linguistics and a minor in Japanese Language. After finishing his education, he settled down there with his wife Kaitlyn and became a full-time writer. In 2011, he moved to Montreal and discovered its vibrant writing culture. In 2015, Ethan moved to Helsinki, Finland with his wife; he works as a props crafter and part time author. His first book, Blood of Midnight: The Broken Prophecy is the first of a new fantasy trilogy. The greatest joy in his life lies in helping budding writers find their voices. In his words: "I like to shake people until cool stuff comes out!"

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