Tag: casting

Did you read Rugged Box Silicone Gasket Seal (Part I) and Part II where I attempted (and succeeded!) at using CHANGTIKEJI Silicone Mold “Super Elastic Liquid Silicone” to make a gasket (seal) for these 3D printed rugged boxes?

Well, here’s the next installment. In Part II we tried to pour the silicone directly into the groove on the bottom half of the enclosure. Which worked but failed, so I guess it didn’t work. There were other factors at play, so I think it could work in some cases. Nevertheless, we’re going to try to “glue” this existing seal into place using silicone.

So this time we took the existing box and seal which do work fine, but have the bothersome quirk of the gasket not staying in place and falling out when you open the box. I drizzled just a little bit of silicone into the groove in the bottom part, then inserted the seal and put some weights on it to press it down into the uncured silicone. In theory the uncured silicone should stick (somewhat) to the 3D printed plastic, and adhere fully to the silicone seal, sort of “gluing” it into place.

Did it work? It did work, as far as it has not fallen out. It seems to be held in place. I have not tried to pull it out, as I am sure I could do so, but the idea was to just prevent it from falling out every time I open the box, so there is some success there for sure.

But remember this seal was made for a box that had a 1mm gap added in for the seal, so more space to fill means a larger/thicker gasket. I think this made everything a little easier.

As I’ve noted before, there’s a bit more experimentation to be done, but I’ve learned a few things in the process so far, and that’s what it’s all about!

See Also: Rugged Box Silicone Gasket Seal (Part II) and Rugged Box Silicone Gasket Seal (Part I).

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If you read Rugged Box Silicone Gasket Seal (Part I) you read about how I used CHANGTIKEJI Silicone Mold “Super Elastic Liquid Silicone” to make a gasket (seal) for these 3D printed rugged boxes.

But I wasn’t completely happy with the results…

I sort of wish there was a way to “glue” it into place, but you can’t exactly glue silicone, because it doesn’t really stick to anything! I do have an idea for that…

The one thing I don’t like with this one is that it easily falls out. If this is a box you open a lot you’ll probably get annoyed with it falling out on occasion.

So I wanted to try a few thing to solve those annoying issues…

Someone on Mastodon had the idea to pour the silicone directly into the groove of the box. (I can’t seem to find that reply right now!) I thought I should try that. It was not easy. It was messy. And I had to do it twice. The first time I leveled off the silicone with a wooden popsicle stick. Once it dried it sort of sunk down a bit… I did it again, this time dripping (drizzling?) it into the groove just a little at a time with a popsicle stick. That gave me a lot more control versus pouring way too much. (Luckily it peels off when dry.)

One other issue is that once dry the lid would not close! I ended up shaving down the lock just a bit and using some good pressure to close it. Again, I may need to mess around with the TSealHeight parameter to get things just right.

Finally, I tested it for water-tightness by doing to paper towel submersion test and… it failed. So not water-tight, and not a good fit.

Also, while the idea to “glue it in place” by pouring the silicone directly in was a good one… it just came out very easily. Maybe because it was so thin.

Anyway, this was a good test! I have another test that I just finished, so keep an eye out for the next post!

See Also: Rugged Box Silicone Gasket Seal (Part III) and Rugged Box Silicone Gasket Seal (Part I).

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Here’s the short version, I used CHANGTIKEJI Silicone Mold “Super Elastic Liquid Silicone” to make these seals / gaskets for the rugged box(es) I 3D printed. There’s a smaller size available as well. I have not used it but it should be the same thing. Keep reading for more!

I’ve mentioned these Rugged Boxes before which are based on Universal Parametric Rugged Box by Rainer Backes, and the design allows for a gasket to seal the lid and bottom, and the suggestion is to print it with TPU, a flexible filament but I’ve been making a ton of silicone molds lately, so I gave it a go. And it worked!

Here’s the box with the seal rendered in orange…

You can export each part separately, so here’s the seal on its own. Again, you could print this in TPU, but the TPU I’ve tried isn’t very soft or flexible, so why not try silicone?

I make a little frame and differenced out the seal (after filliping it upside down) and then I printed it.

Here’s the print. (And another frame for another box off to the side. The silicone doesn’t stick to the PLA plastic so it peeled right out. I should note two things. First, I should have done the silicone pour on an even surface. In the past I’ve used a level and shimmed up a piece of flat stock to make sure the mold is nice and level so the silicone fills the mold without unevenness.

Second, I don’t have a photo of this, but after the silicone was set I grabbed a razor blade and scraped it across the top to clear off any little overflow strings and give a nice clean edge to the casting.

Here’s the seal in place after the silicone was fully cured. This CHANGTIKEJI “Super Elastic Liquid Silicone” is very soft and rubbery, which is a good thing, but it may not be the best thing… I sort of wish there was a way to “glue” it into place, but you can’t exactly glue silicone, because it doesn’t really stick to anything! I do have an idea for that…

I think next time I’ll make the mold slightly smaller so there is some stretch when placing it into the slot of the box. The one thing I don’t like with this one is that it easily falls out. If this is a box you open a lot you’ll probably get annoyed with it falling out on occasion. On the other hand, if this box is outside and rarely opened, it would probably be fine.

You’ll notice that there is a nice layer of silicone showing between the lid and the bottom of the box. There is a parameter named TSealHeight and while it is set to 0 for a default, I tried it at 1 for this box. So the seal has a “T” shape profile to it. I think next time I’ll try the 0 value again which will make the seal thinner and it should not even be seen when the box is closed.

Anyway, this was a great experiment, and very successful! I’m working on an outdoor box next, and a good seal will be important. I’ll most likely use ASA or PETG instead of PLA for the next one.

If you try this using the silicone I mentioned let me know how you get on. (My daughter originally bought some for a school project and I ended up liking it and ordering my own.) I’ve used Smooth-On silicone in the past and it’s worked well sometimes and not as well other times, that could be due to the scale I was using at the time. This stuff is a 1:1 ratio and when we measured in grams it worked great. We even did some large pours and measure in ounces (not as accurate) and it turned out just fine.

See Also: Rugged Box Silicone Gasket Seal (Part II) and Rugged Box Silicone Gasket Seal (Part III).

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