geekhack
geekhack Projects => Making Stuff Together! => Topic started by: Mouse on Mon, 27 July 2015, 08:26:49
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I just finished pouring my first castings, and I'm having way too much fun. I threw all caution to the wind and tore up one full mold and one partial while I got an idea of how the plastic resin I'm using works. I made some impressive mistakes, and changed my process in between each casting.
From left to right, my first to my fourth casting.
(http://i.imgur.com/6V7lWGB.jpg)
Here are all four that I cast. Lots of porosity, both from my changing the orientation of the mold and failure to appropriately sprue the mold. I don't have all the equipment I want yet, but I was anxious to get started and just decided to wing it.
The first keycap, the scary dark blue one, involved me carefully painting the resin over the stem half of the mold, then filling the exterior half of the mold and pressing them together with a vent hole at the middle of the two halves. This was also before I had read the directions completely, and I failed to stir the resin sufficiently. It took about 5x as long as it should have to set up. The tip of the stem broke off inside, but I was able to retrieve it. I also learned that when using 10mL of resin, five drops of coloring is way too much. Fits on my keyboard (6Gv2 Red) but it's ugly, loose, and the other keys make fun of it.
The second keycap was made immediately after the first, with a portion of the stem mold missing. I had also slightly enlarged the vent hole, which seemed to help, almost as much as stirring the resin correctly. I did not paint the stem half of the mold, and it's just all full of bubbles. It fits on my keyboard quite smugly, but it's tall enough that the other keys comment on it. Part of that is probably because I did not cast the full stem portion, as part of the mold remained in the first casting.
Number three had some marked improvements. The resin set up quickly, and a lot of the surface porosity was minimized. I quickly painted both halves of the mold with resin, filled the exterior half and pressed the two together. There are several large bubbles, however, caused by the fact that insisted on beginning my pour with the mold separated, then squishing it together. I had also retrieved the bit of silicon rubber trapped in the stem of the first cast, and painstakingly replaced it. It was pretty gratifying when it didn't get jostled out of place in the casting. However, it did get stuck again. I wanted to see this work, so I dug it out and tore it into two peices in the process.
When it came to the forth, I had decided to change things up. I added a second hole so that the mold would pour down onto the stem half, enlarged the previous vent hole, and poured resin through a haphazard sprue that I had cut into the rubber mold. I had also reassembled the stem. Predictably, the poorly made sprue did not allow enough resin to flow to my pattern, but it did allow some. When I opened the mold and saw it, I decided to go for broke and do a second pour. The stem had come out really nicely, most of the debris you see is from my attempt to dig out the pieces of mold stuck inside. The first pour is white and the second pour is blue. I captured the stem really well, but I have some major bubbles near where the vent was attached. It fits on my keyboard, and it fits snugly. I'm considering doing a third pour to fill the porosity, but for now it's time to get some sleep.
(http://i.imgur.com/fRMHFd3.jpg)
I think tomorrow night I'm going to pour some more molds, and pay a lot more attention to my spruing so that I can get sufficient material to where I need it quickly. I also really want to find some way to spin the mold in such a way that centripetal force is helping the resin flow. I also want to play more with additive techniques.
I just painted resin onto the cap on the left to see how it would come out. And I can capture some really sharp detail that way. I'm borrowing heavily from my dental lab experience here - when we made acrylic nightgaurds, we would alternate sprinkling the liquid monomer and the powder polymer over a dental cast until it was approximately the size and shape we wanted, then finish it down. This is the additive technique I'm trying to imitate for an entirely different outcome. For the second, third, and fourth cast, I slathered resin over the mold on the top right of this photo.
(http://i.imgur.com/MabEMOv.jpg)
And I got some pretty good capture, even after spending five minutes digging the sad, shredded remains of my abused mold out of the stem.
(http://i.imgur.com/abDhvLV.jpg)
Side by side, additive on left, poorly planned casting on right.
(http://i.imgur.com/3wTV2x4.jpg)
And finally, since i have no idea what the capabilities of these materials are, having never worked with them before, here's a gentle pour into an open half mold, just to see how accurate this stuff can get. And it's pretty accurate. Just to give you an idea of the amount of operator error involved here, I figured I should include what this stuff can do when someone isn't screwing it up left and right.
(http://i.imgur.com/gJ8xNFG.jpg)
Anyway, that's my first crack at making keycaps. I feel like I've got a better handle on what I'm doing. Now it's time to do some research before I keep buying stuff and trying stuff. Or maybe not, I had a blast. I'll keep posting overly long posts about screwing up if people want. Screwing up can be fun!
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Nice little build log :). Thanks for sharing. Sorry that the blue cap doesn't fit in and is made fun of. Poor lil fella
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Cool progress :)
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which one is better casting or 3d printing?
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Sweet log! Trial and error is part of the game. Nice adjustments you made. Keep it up! What type of casting resin are you using?
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Throwing caution to the wind and having fun. I like it.
I too am "figuring out how to make keycaps" but just getting started. It is nice to see I won't be the only one just getting into this crazy hobby. Have you checked out the Key Forge thread yet? Seems like he had similar results on the first few attempts.
Are you looking to just have some fun making "normal" keys or eventually create some artisans?
Keep posting results and lessons, it would be nice to see how you progress.