Joseph Meditz wrote:
Raymond Koonce wrote:
Hi RATs,
Here's a link to a project I've had on the bench for a while and got
finished today. I learned quite a bit on this one.
http://www.timebanditaudio.com/47%20Amp/Carmen47.html
It sounds as good as it looks.
Comments, questions?
Regards,
Raymond
It sure is pretty! I then looked at your other amps which are also
very beautiful especially with that red powder coat.
How did you do the silk screening? Is there an amateur kit available?
Joe
Hi Joe,
Thanks! I sure like building these things. Everybody like the red color.
The silk screening is not too hard, but it's hard to find information.
Here's the process I used:
You can see the graph paper I used for layout purposes. I took scans of
the layout paper and inserted them into a vector drawing program as a
layer. On another layer I did the artwork and then removed the scans.
I printed a positive of remaining artwork layer on our large format
plotter at work on clear film.
The next part required a little practice. I bought some silk screening
supplies from a place in Maine which I found on the internet. I bought
from them because the salesman was helpful and they had what I needed.
I bought a screen of the appropriate size already stretched in a wood
frame. The photo emulsion comes in two parts which are mixed and poured
onto the screen. Push it into the mesh with a rubber squeegy. Tip:
get a squeegy that fits the frame. It's easier to get an even layer.
Let the emulsion dry overnight in a completely dark area. I covered
mine in a cardboard container.
Next step is the exposure. There's a chart that comes with the emulsion
that gives exposure times with different types of light. I used a 150
watt clear incandescent in an aluminum reflector. IIRC, it was mounted
17" above the screen. The screen is laid upside down over a black cloth
to avoid reflections and the artwork is laid over that, ink side down,
so you see the artwork in reverse. Lay a sheet of clear glass over the
artwork to hold it tight against the screen. Expose the screen to the
light for about 1.5 hours. When you remove the artwork, mist the screen
with clear water and the unexposed areas under the artwork will start to
dissolve. Immediately take the screen outdoors and spray it with your
water hose at high pressure. The unexposed emulsion washes out, leaving
the screen mesh for the ink to go through.
Align the screen over the work, pour a little ink into the frame and
squeegy it over the work. 10 seconds and it's done. Lift it carefully
and let the ink dry overnight. I sprayed a clear lacquer over the ink
for protection.
It's really easier than it sounds here and for $75 I got the screen,
some tools and enough emulsion to do 1000 amps.
Best regards,
Raymond