A couple weeks ago I decided to finally take a stab at resin casting. Just thought I'd share some progress pics even though I feel like I failed to document the process thoroughly.
This was the start of the first mold I made. I wasn't sure if I was going to lose any caps to the mold making process, so I went with DSA blanks as they were the only spares I had. Since then I've learned that the silicone does no harm to the keys and I'm pretty confident about using caps from real sets now. Rather than use a clay base as I saw others do, I figured why not just hot glue the keys down so that they don't float up during the curing process. Man was that a mistake! The edges of the keys don't form a perfect seal against the cardboard base, leaving just enough room for some silicone to creep in and make a mess that needed to be cleaned up with an exacto. I used some sculpey clay for the alignment pins, which actually seemed to work pretty well.
Here's right after pouring the first mix of silicone. It's a Shore 30A silicone, which I initially thought would be too flexible after doing some research. However, I've found 30A hardness to be a good middle ground, more than suitable for casting. The silicone also has a long pot life, which left me plenty of time to work out any bubbles without pressure or vacuum. A little trick I learned was to leave the poured silicone on top of a dryer while it's running, the vibrations help agitate the silicone and cause any bubbles to rise and pop.
Jumping ahead, I needed to construct my own box this time since I realized the box I used previously was way too shallow for another pour. I essentially re-purposed an amazon box and used some hot glue to seal the pieces together. What's not shown here is the process of spraying the mold release. I can't begin to tell you how essential this is, mold release is the best thing to happen since chocolate cream pie. Before spraying the release out of its aerosol can, I placed a few pieces of tape over top of the keycaps so as to not get any mold release on them. After a few light, even coats she was good to go.
Here she was after the second pour. As you might notice there are some white sticks sticking out of the mold. These are some q-tips with the ends cut off, which act as sprues for excess resin and air to escape. Initially I thought to use the sprues to introduce resin into the mold, but later on I realized it's much more effective to pour resin into the two mold halves and then sandwich them together. If you're wondering, the q-tips were hot glued to the corner edges of the keycaps. Sadly, stock DSA keycaps aren't nice and thick so it was difficult to place the q-tips properly and I ended up with a mess of hot glue.
When all was said and done I was left with this. Of course I immediately grabbed some resin and attempted my first cast. Unfortunately, I wasn't aware of all the issues that came with using Alumilite Clear to gravity cast. I bought it because it's a urethane resin rather than epoxy, it's a Shore 78-80D, and it has a decent 7 minute pot life. This resin also boasts a 2-3 hour demold time, however I quickly learned that is only the case when curing the resin in an oven at 140 °F. Otherwise it takes around 12 hours to demold at room temperature and about 24 hours to reach full hardness. Also keep in mind that if using Alumilite Clear, the B side will gel up if exposed to any temperature below 65 °F. So before doing a cast make sure to heat up the B side by submerging it in a bowl full of hot tap water for 15 minutes or so. Alumilite Clear can also only be mixed 1:1 by WEIGHT, not volume
I encountered some problems when I tried to use a scale that wasn't precise enough and ended up with some dud casts that never fully cured.
Voila, my first successful cast. While the tops are almost where I would like them to be, the bottoms could use a lot of work. This is because sprue removal proved to be a much bigger pain than I anticipated, it was quite difficult cutting away the excess with the tools I had on hand. But, the thing I'm most happy about is the way the stems turned out—all of these keys fit perfectly on my MX board with no issues. They actually make a pretty okay WASD or arrow set if DSA is your profile of choice.
Here is another set that didn't turn out as well. It has all kinds of coloring issues due to using high amounts of dye with a small batch of resin. On top of that, all kinds of little micro bubbles formed on the surface.
So what's the plan for the future?
Well, I don't really like DSA profile all that much, but if anyone has an interest I'd be glad to continue making some. I've recently just finished up a new mold featuring my first sculpted cap, a topre esc blank, and two more DSA blanks (see below). I did a few things differently this time around, most notably I went with a clay base so that I could get a nice seal around the edges of the keys. I also opted to leave out the sprues, since they were only a hassle in the previous mold. We'll see how that goes, honestly I'm not sure if it'll work out. I'm really big on topre and love my HHKB to death, so I really hope these esc blanks turn out okay enough to use. After I get enough decent casts I'll probably try and make one big mold with tons of goodies in it. That way I can churn out more stuff and work with larger batches of resin, allowing me to change up the colors a bit more.
Anyways that's all for now, any constructive criticism or comments are greatly appreciated. Look out for some updates after this next batch is finished curing. Oh and a huge, HUGE shout out to all of the folks whose works helped me along the way: Booper, Binge, Katz, RP, KeyKollectiv, and _joe_king are just a few I can think of off the top of my head, thank you guys so much!
The first topre esc blank seemingly turned out much nicer than I expected. Looks nice on my HHKB next to KeyKollectiv's CMYKeys hehe
There will be many more of these to come, stay tuned!
Something heart... something something cap.... I have yet to give this an official name
Turned out okay for the first cast, but ran into some issues with the white resin leaking over top of the heart. That most likely happened because I wasn't careful and the heart plopped out of the mold before the second pour. Placed it back in of course, but the ever so thin seal that was there before was no longer. Ended up having to scrape off the leaked resin, which is why the surface of the heart is a bit rough.
Side profile.
Just showing the surface imperfections caused by the excess resin.
Damn, has it really been 10 months since I last casted anything...
Wouldn't call this update a progression—got bored yesterday and saw my resin sitting in the corner, decided to show it some love.
Rushed this cast and forgot to incorporate a lot of my old techniques, but I loved the color enough to post anyways.
DSA Heart-A-Clack, Topre Blank, and DSA Blank in 'Strawberry Cheesecake'