Sep 12, 2019

Three months ago, after many good years of service, my SteelSeries Apex keyboard started to give out. Presses would intermittently register multiple times or not at all. It wasn’t all that surprising–it had lasted longer than any keyboard I’d owned and I’d worn many of the letters off the keycaps years ago. I knew it was time to finally take a plunge I’d been considering for a while: I needed to buy a mechanical keyboard.

Some say mechanical keyboards are a rabbit hole: You buy one, then end up with five. I’d say that’s mostly accurate, but in my case a massive understatement.

Shortly after buying a new Akko X Ducky keyboard, I decided I’d like to try other switches, which led to purchasing sampler packs, which led to realizing if I wanted to use my favorite ones (ZealPC Zilent 65g are to die for), I’d need to build my own keyboard. That led to buying a Levinson kit off keeb.io and then to searching for cool custom keycaps to put on it.

My fascination with the keycaps was immediate. I had never considered being able to choose the look at such a granular level or have artwork embedded within the keys. The opportunities for personalization were endless. Perhaps even more interesting than the end result, though, was the process of making them. I quickly decided that instead of buying custom keycaps for my Levinson, I’d build them just like I was building the rest of it.

Creating keycaps is far and away more complicated than soldering together a custom keyboard. I knew this when I started, but these past few months the reality of what I decided to do really set in. I converted half my basement into a shop with vacuum and pressure chambers, air and heat dryers, an SLA printer, ultrasonic cleaners, and polishing tools. Syringes and popsicle sticks litter the repurposed desks, and nearly a thousand dollars worth of chemicals fills the multiple new shelving units I had to buy to hold them all. A fume hood hangs over a wall of respirators, gas and vapor filters, and UV goggles. Where there was once a window, there is now an exhaust.

Something to understand about making custom keycaps is it’s not a significant stretch from making one to making a thousand. The equipment needed to even make the first one properly is so extensive (and expensive) it quickly dawns on you that stopping there is insane. You need a miniature factory to make high quality keycaps, and if you’ve got a miniature factory, you might as well run it.

When I started this, I didn’t intend to make money off it. By the time I had my process refined, though, I’d started reading up on the legal and financial requirements. I learned about different business structures, how to file quarterly taxes, what state and local permits I’d need, and how to track all the expenses. The sheer amount of auxiliary learning needed was unexpected, but fascinating. What size are shipping labels? Is a thermal printer warranted? How do you manage customs forms for different countries? What sort of agreement do you need with a parcel carrier to use prepaid return labels? Which materials do you pay tax on when buying versus collect tax on when selling? Do you need insurance? Which new accounts do you need to open at the bank?

Beyond that are the logistics issues of running a workbench as a professional shop with an internet presence. How do you line up new products on a photo back plane to get the same shot every time? How do you configure product lighting? How do the APIs work to pull listings onto your website? How do you store and track stock in real-time and ship it quickly?

And never mind the thousands of questions regarding the actual process of making the keycaps themselves, which is still largely uncharted territory even in the casting community. With a few notable exceptions like a pressure pot, the equipment, timings, processes, and art methods are as different as the keycap makers themselves. StackOverflow won’t save you here, but in a way that’s exciting.

I’m happy to say that falling down the rabbit hole has worked out so far. My new shop, Cherry Festival, has completed over 100 orders in its first two months of operation and I now have a place on people’s keyboards in most US states, Canada, the UK, Norway, Sweden, Germany, Australia, and even Japan.

Some day I may even get around to building that Levinson keyboard that started all of this.

Apr 23, 2019

After my last failure to get a proper cure in my SLA printed masters, I reached out to my local distributor and Smooth-On to see if they had any recommendations for improving the quality of the curing.

It turns out photopolymer resin is fundamentally incompatible with platinum silicone curing, and while this can be mitigated to some degree by the finishing process (especially heat treatment), a boundary layer of uncured silicone is still present where the mold comes into contact with the master.

There’s a Product for That

The technical staff at Smooth-On were very helpful in explaining that they normally don’t recommend using platinum cure silicones in SLA prints, but that if I insisted, I should try their products Inhibit X and XTC-3D. I’m afraid I had to insist!

Inhibit X (MSDS) is a very thin, clear liquid with copious flammability and explosiveness warnings that brushes onto the SLA part and reacts somehow with it. It applies very smoothly and retains all detail, leaving even small imperfections like the print striations clearly visible in the finished part. It should not appreciably change the shape of anything, so it’s very good for molding. You apply it liberally in at least two coats, allow time to dry, and then cover with Mann Ease Release if you’d like. Edit: Better yet, if you can fit your part in a jar with it, soaking the part for 5 minutes works absolute wonders.

It’s not the cheapest chemical, but you absolutely get what you pay for. After performing my finishing process from part 1 and applying only Inhibit X to test, my molds cured to a very nearly usable state.

Left to right: No coating, light Inhibit X, multiple Inhibit X dips

To make the molds work even better, I then added XTC-3D (MSDS) to the process, applying it before the Inhibit X. This is a very inexpensive, clear two-part substance that you mix together and then coat onto the part. It is self-leveling and provides a very pleasant visual finish once dry, smoothing out any striations and imperfections. It has the added benefit of providing additional insulation against cure failures, allowing Inhibit X to really do its work. You can also create some pretty awesome stuff by mixing colors and metal powders into the XTC-3D for some very impressive part finishes on your other prints.

XTC-3D adds significant clarity to parts

While I don’t necessarily care about striations on my mold since the areas where the silicone contacts the SLA part are not essential to the shape, the XTC-3D is cheap enough that the added layer of protection is often a straightforward choice. While it does change the shape and tolerances of your master slightly, you can generally apply it in a thin enough coat for it not to be a problem, or you can thin the solution further with Epic Epoxy Thinner (MSDS). I like to blast any fine details with an air gun while the thinned XTC-3D tacks to ensure there’s no buildup in small corners. Edit: With a long enough Inhibit X soak, you really don’t need this. It’s neat to have around, though.

Use a Faster Curing Silicone

Another way to beat silicone’s reluctance to cure in the prints is with a much faster cure. Mold Star 30 (MSDS) takes 6 hours to cure, but if you’re willing to sacrifice pot life, Mold Star 16 FAST (MSDS) only takes 30 minutes and seems to work better in general with SLA prints. I am extremely satisfied with the results.

To cure even faster, you can hold the temperature a little higher during the curing process. Higher temperatures significantly reduce the pot life and cure time of platinum cure silicones, so I like to vacuum degass and pour my silicone at room temperature but then place the masters into the toaster oven under gentle heat to really expedite the process and ensure a great cure.

Light heat only–don’t deform your masters

Go for It

So there you have it: If you want to use platinum cure silicone with an SLA master, just do this:

  1. Isopropyl alcohol bath/scrub
  2. Water rinse
  3. Air Dry (can speed this dry up with an air gun)
  4. Bake (recommend 200F for ~3 minutes)
  5. UV cure (follow resin directions)
  6. Optional Smooth-On XTC-3D coat (optional Epic Epoxy Thinner, watch out for small details and corners)
  7. Cure 4 hours if using XTC-3D
  8. Mann Inhibit X coat/dip
  9. Air dry
  10. Mann Inhibit X coat/dip
  11. Air dry
  12. Mann Inhibit X coat/dip
  13. Air dry
  14. Mann Ease Release 200 coat (brush into all fine details)
  15. Air dry
  16. Mann Ease Release 200 coat (light spray)
  17. Dry
  18. Fill with degassed Smooth-On Mold Star 16 FAST
  19. Keep warm or bake at low temperature (recommend 125F for 30 minutes)

This process turns out a great mold every time with ELEGOO translucent resin on my SparkMaker SLA printer.

I’ll now be moving on to pressure casting finished parts in these, which I’m sure will present plenty of new challenges and solutions.

Apr 14, 2019

Update: See Part 2 of this series for a repeatable procedure to make great molds in SLA masters. SLA (stereolithography) printers are excellent for creating finely detailed parts with beautiful finishes. Their detail and ability to create complex shapes without the extensive support required on FDM printers make them theoretically ideal for creating masters for […]

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Mar 4, 2019

I love using YUIDoc for my JavaScript projects because the setup is dead simple and the default theme has everything I need, including search and good markup for SEO. It’s no secret it’s a little outdated, though (does Yahoo! even still exist?). If you’re using more modern JavaScript practices like CommonJS modules, you’ll probably run […]

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