Sunday, February 9, 2014

Pseudo-Solder Paste, Shiny Knobs, and Jason Whisperers

Roughly three quarters of the time it takes for a project to be completed falls into at least one of the following categories:

a) waiting for things to get shipped
b) waiting for funds to appear to buy materials

And while the prudent observer might point out that neither of these things would happen if I planned ahead of time, it's worth mentioning that b) is almost always the precursor to a), and b) is a struggle that I probably won't overcome until I get a real job. lol.

Anyway, all this waiting is what led me to delve slightly deeper into the world of hand-etched pcbs. Most notably, that thing where you tin your boards.

Done mainly to protect the copper from oxidizing, I was initially repulsed by the idea of having to spend hours pushing around a blob of solder on a board until I got a semi-acceptable layer on my traces and planes (inevitably causes n solder bridges to form). However, everything changed when the fire nation attacked I discovered this page.

The process entails covering your board with flux and grating solder over it, forming a pseudo-solder paste, which you then apply your iron to. 

It's magical.

(bunny music courtesy of the youtube video editor)

And so I spent the better part of an evening working on finishing the board and populating as much as I could of the tube amp in progress. Special thanks to Kramnik for giving me a pair of 9 pin tube sockets for the time being.

*sockets not pictured
Of course, this project wouldn't be complete with shiny knobs.

Definitely worth the $3 from Mouser
This weekend was then topped off with getting the long overdue scooter in a rideable state.

Subdued last time by a thought-to-be zorched motor controller, the ailment was remedied by none other than Charles, the Jason-Whisperer.

It simply took one well timed roll of the drive wheel to trick the no-stall detection on the Yiyun yk85s. Or what is academically known as wizard magic.

And while born from black magic, the scooter was a little disappointing on its maiden voyage due to a less than charged battery. (Hence the lack of video.)

Nevertheless, jankiness abounded as the inaugural ride involved more than a few zip ties.

Totally legit

The original bottom cover was a panel of acrylic that sat flush against the two legs of the u-channel, however,  I underestimated the depth of the battery pack with PET insulation, causing the cover to bulge. Luckily, I happened across some polyethylene scrap at MITERS (and by scrap I mean large and kind of melty piece). 

The lesser known geological formation, Mt. Plastic 
After two hours on the mill, I had a piece of specially machined Tupperware. The plastic was then secured to the bottom using the original drilled and tapped holes for the acrylic bottom cover.

Scooter Sans Brake
Now in scooter form!

All that's left is machining a rear end out of polycarbonate and solvent welding it together; I've since dropped the proposition of making the back out of aluminum due to the high cost/low benefit.

Oh, and the brake. Yeah.