How Does Silicone React In A Vacuum Chamber

How Does Silicone React In A Vacuum Chamber

Hey guys, we are back in the lab again for another silicone casting experiment You might remember in a previous video, I tried casting some of these pokéballs with silicone. And the problem we ended up having was bubbles that got trapped in the rubber, which transferred to all the success of castings. So in this video, we’re gonna try recasting these pokéballs, and see if we can get rubber molds that are completely bubble-free. So in a follow up video, we made this thing, this is a vacuum chamber that’s designed to suck the air out the silicone before we pour it. So in this video we’re gonna put it all to the test, we’ve got our vacuum chamber, we’ve got our pokéballs and we’ve got some more silicone. So let’s get busy in making some more rubber molds. Now I showed you in a previous experiment that you could use glass cookie jars as your vacuum chamber, but for this experiment I’m going back to my pressure pot. Because its wide enough to accept this popcorn dish that I found at the dollar store, this is only about a buck And it fits perfectly inside the container here, you can see the lid fits on and everything’s flush. And because it’s paper, it’s disposable which means a very easy cleanup. Alright, update guys we got our pokéballs set and positioned and I took a little bit of a different approach this time, let me show you what I did. First of all I took the Pokéballs and set them upright, so the button is facing towards the ceiling, this way if there are any accidental air bubbles trapped inside, they should be able to follow the lines and escape. Second of all I took some clay and made and made a big base around the bottom, and this is to help form a reservoir, so when we’re pouring molten gummy, wax, or molten aluminium it’ll have a reservoir to draw from as it cools and keep the pokéballs full. Hopefully with those improvements, we can make ourselves some perfect silicone moulds. So now we can mix up a new batch of silicone and use our vacuum chamber, to suck the air bubbles out, then as we pour it we want to pour it in a long thin stream far away from the Pokéball itself. As the liquid level rises, it should push any trapped air out and give us a perfect silicone casting. Oh, it’s so satisfying. We’ve got our silicone and our catalyst blended, but it’s full of air bubbles. So now we’re gonna transfer it to this popcorn container, stick it inside our vacuum chamber and suck those air bubbles out. Now we actually wanna fill this up about a third of the way for my understanding, cause the air bubbles are going to go crazy! And unfortunately that’s more than a third of the way. So we’re gonna have to be very careful. Let’s go ahead and extract these bubbles. [Vacuum chamber starting] Now I can actually regulate the airflow here. You can see its digging deep down the silicone now and pulling out all those bubbles. [AHH] It’s not giving them the chance to pop Oops, uh oh. (laughs) Made a mess! Ok, so lesson that we just learned, when you’re putting silicone in a vacuum chamber you only want to use about one third of liquid, because the bubbles will rise up and contaminate everything. If there’s not enough space for the bubbles to come up and start popping, they’re gonna hit the lid and everything will deflate it’s just gonna repeat the process. So you need to leave enough of a gap that the bubbles come up, and have a chance to escape. Ooh, that was close, that was close… And that right there my friends is the magic. So that’s kind of cool, if I move it around I can actually like access different parts of the silicone and get that going faster. Oh wow, that looks amazing! Its very cool, the way that, that churns. You can see its digging deep down in the silicone now and pulling out all those bubbles. The longer we let this sit, the more air is gonna come out. And ideally it’ll get to the point where there are no more bubbles whatsoever. But I’m a little nervous on timing because I wanna get this silicone poured before it actually sets up, so I might just take it out now and pour it, there we go. It looks like it”s ready! We’ve sucked out quite a few of the air bubbles here and now i’m excited to see what difference this makes now as we pour this, the key is to pour a long thin strand next to the Pokéball but as far away from it as we can get we don’t actually want it going on the pokeball itself you can see that I’ve painted a thin layer of silicone into some of the problem areas so that as the bubbles rise it wont get trapped up there Slow and steady wins the race that might even be too much slow down Grant Oh dang! I’m messy that’s looking beautiful oh my gosh that is looking beautiful so cool guys our molds are filled up to the top and these are actually looking better than I’ve ever seen before in fact if you look if you look at the surface of these molds it almost looks like a crystal clear lake reflecting everything perfectly which is a really good sign it means we probably don’t have any bubbles in there now there are a couple of lessons I learned while doing this experiment today number one I wouldn’t of mixed the whole batch of silicone at once working with so much silicone is very difficult and we are fighting the clock because this stuff sets up in about 30 minutes so if you try this yourself divide your silicone into different batches mix them one at a time number 2 when your mixing this it’s been suggested to mix it by hand because you will introduce less air by doing that by using something like these mixing beaters that I was using it’s actually pumping a ton of air into there which means it takes a lot longer in the vacuum chamber to extract all those bubbles back out so if you have the option don’t use a mixing beater mix your silicone by hand so that’s it for today because these things are gonna need about 24 hours to cure so we are gonna let them set over night and we’ll take a look at the final result tommorow Thanks for joining me for this project I will be looking for you in the next video talk to you then shoot… made a mess I will have to clean up later hey guys thanks for watching and remember I’m giving away prizes now on every new video all you have to do to qualify is subscribe to my channel, ring the bell and select to be notified when my next videos get released the secret link to my giveaways will be pinned in the comments for the first 12 hours if you like what I’m doing show your support right now by giving this video a big thumbs up and share with a friend I love you back and I’ll see you next time


  1. Can you lot try and burn or oxidize steel wool with a 9 volt battery inside your vacuum chamber ??,…please ?

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