If you ever have the need to visit the Edison Museum in West Orange NJ (about 8 miles from our NJ house) you can see the various spots that spots in which he would take naps!
Good luck on the patent.
In general I'm quite suspicious. I've seen plenty of evidence here and elsewhere that high frequency ultrasound works just fine as a record cleaner.
Not for long.
jeff
In my cheapest microphones I have the loaded PCBs made in Pittsburgh, they cost me $16.00 ea. the rest of it including packing brings it to $25.00. The folks who have them made in China wholesale them a bit above $90.00.
Quantity certainly has a lot to do with it as does amount of human labor versus machine time.
I just spent $500.00 on the material to make 300 cases. Human labor will be one day. Of course the machine to do most of the work sells today for $185,000.00!
Some things are cheaper offshore, but it has to be quantity and little skilled labor required.
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Except electrostatically EVERYTHING sticks to PVC. If you ever have the horror of machining the stuff, you find every part of your lathe/mill completely covered in PVC.
Ed, did you ever own a Questar? Made in Pa. My dream in high school was to own a 7" Questar now at $13,000 not as unaffordable. Decades later I bought a used loaded 7" Meade refractor for $5000 and used it 2 or 3 times, there must be a message there. I've tried to donate it to a high school science program but the shipping is large.
I did not, but 40 years ago (sounds familiar?) I polished my own 8" parabolic mirror, took me almost 1 year. Also build my own Foucault knife-edge and Ronchi test benches with the slit made out of razor blades, the guys at the fab were so kind to coat my mirror with aluminum in a Balzers electron gun deposition system. I had to clean it myself before deposition though, including a nerve wrecking HF 1:15 dip.
Got stuck in the tracking mechanics and never finished the assembly, but the optics was world class. I still have the 8" parabolic mirror, unfortunately the flat elliptical mirror was lost during a move some 30 years ago...
Derfy,
Next time machining PVC use a cutting fluid pump with tap water to which you add a small amount of liquid dish soap.
Now if you insist on machining it dry, then be sure to wear a dust mask.
If you don't want to do either, can we talk about my buying a life insurance policy on you?
Dry inside an enclosure, mask, and one very upset shop vac.
There are plenty of reasons to put a life insurance policy on me, but this one is lower on the totem pole.I regularly have to do some heroic ultrasound cleans on plastic parts to get them clean clean clean. Heated bath, liquinox (or alconox, plenty of equivalent detergents), the whole bit. I find metal parts infinitely easier to clean. (But wafer bonding personally takes the cake in fussiness.
I always wanted a nice telescope, and a friend had a 6" Celestron which was OK, but all my free time and money went into ham radio back then. I couldn't afford to buy so I made a xtal transmitter very much like this one:
https://www.w8ji.com/images/Transmitter%20design/40M%20CW%20Transmitter%20example.jpg
Keep in mind high-power RF semiconductors were wayyyy expensive (like big telescope mirrors and and likely just as fragile) in the mid-70's, so us po-boys teenagers had to use tubes to generate high-level RF! Fortunately the power transformers were easily salvaged from TV sets.
My end-fed long-wire antenna was launched high into the trees in my parent's back yard using an Estes rocket trailing #30 enameled...the rocket hung up there until winter...
Every new thing made when you are first learning becomes a memorable milestone in the process...but I think neutralizing HF transmitters was less tedious than grinding mirrors...
Cheers!
Howie
https://www.w8ji.com/images/Transmitter%20design/40M%20CW%20Transmitter%20example.jpg
Keep in mind high-power RF semiconductors were wayyyy expensive (like big telescope mirrors and and likely just as fragile) in the mid-70's, so us po-boys teenagers had to use tubes to generate high-level RF! Fortunately the power transformers were easily salvaged from TV sets.
My end-fed long-wire antenna was launched high into the trees in my parent's back yard using an Estes rocket trailing #30 enameled...the rocket hung up there until winter...
Every new thing made when you are first learning becomes a memorable milestone in the process...but I think neutralizing HF transmitters was less tedious than grinding mirrors...
Cheers!
Howie
