anelok: the Y-Box paint job, part 4: alternatives
werner at almesberger.net
Sun Nov 17 10:05:13 EST 2013
I have several ideas for solving the problem of internal paint
1) the easiest approach would be to avoid mechanical stress on the
paint by masking areas where case parts meet. That would create
a bright band since light is reflected on the two walls before
being absorbed by the paint on the inside of the inner wall, but
may not look too bad. Here's one of the cases with the paint
scratched off in one corner:
One issue is that the PCB is also held by the case and thus
rubs against the inner wall. This could perhaps be solved by
adding a gap and constraining horizontal PCB movement via some
structures away from the wall, e.g., a pair of columns, similar
to the LED "pipe".
2) a similar approach would be to add a gap between the case parts
and holding them together with screws. One problem with screws
is that making precise holes for them would require a two-sided
milling process, which exceeds what my machine can do.
3) applying the paint on the outside. This would largely protect it
from internal scratching but it would be exposed to scratching
from the outside and also the "object inside acrylic" effect
would be lost.
I tried this on a set of parts with bad geometry (the case
wouldn't close properly when the PCB is inside.) First, the
The paint is a bit bumpy. This is what happens if you get it
Perfect reflections - good enough to defeat the camers's
auto-focus (it even did it two times in a row.) Not sure why
the two are so different. Maybe I didn't mix the paint well
enough - I'm still new to all this.
This is what the case looks like with the drop of masking fluid
I used for the LED window removed. The damage in the upper front
edge comes from difficulties removing the part from the workpiece,
again caused by bad CNC settings.
This is what it looks like next to a case painted from the
I'd say the result looks quite acceptable but less fancy than the
other one. It also seems to attract dirt a lot more.
4) a mixed solution: paint the top surface from the inside (so that
the LED/OLED window looks nice) and paint everything else on the
outside. This means that I need good masking at the edge of the
The masking worked rather well and the result looks promising.
I'd be a bit worried about paint easily getting rubbed off at the
I think I'll aim for approach 1 for now. This means that I'll have to
add a few holes in the PCBs, make the cases a little wider, and put
some columns into them.
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