Farnsworth Discussion

I've used PCB Etchant available at Radio Shack for about $10. It took me 20 minutes to burn my first project. I swish the solution around to make it work better. No need for wires and electrodes.

All it takes is a little determination and research to get this part done. Trust me, anyone can do it.
 
Here are a bunch of pictures from my mad scientist lair.

They are in the reverse order from when I took them. Last is yesterday's test bed. Next is today's test harness and the very very blue liquid.

Burned the grill and rectangle deeper tonight for about an hour then applied a wash to the numbers and name.

Niece can't wait for it to be Christmas.
 
My thought is the 'field tested' Farnsworth. One that has survived even when the agents didn't.

Next up is the drilling and shaping. Only 10 days till I need to have it completed!

Senjak
 
Finished sizing and drilled the holes tonight.

Happy belt sander went slow as I worked it down to size. Much test fittings. A little annoying that the Minneapolis weather has been full or rain the last few days.

Then came the drilling.

1/4 inch board above
1/2 inch board below

For the small holes, I had the upper board half exposing the plate with the drill points marked. I drilled from the back of the plate.

It jumped around a bit, but these were small holes.

For the big hole it was another matter entirely. I took the guy at the hardware store's warnings/advice to heart and clamp everything together.

And then I clamped the rig to the drill press for the big hole.

Also, I taped down and marked the two boards so that I would know where the center of the Farnsworth plate was.

The big bit tended to stick. lots of letting up on the pressure and then slowly 'bouncing' it down little by little.

The hole was clean, but slightly larger than I was expecting. I don't think I'll be using the pins on the side, as there really isn't room for them. On the plus side, one of the domes I have fits really nicely; however it isn't the one that I like the best as it sticks up lots.

Perhaps with a spacer I'll be happier with it.

Test fitted all of the components, a little filing was required on the red 1/4" hole. Perhaps I had the wrong bit. Could have happened.

I repainted the depressed bits that I want dark and will let it dry before applying clear coat -- most likely tomorrow.

Oh, and in case it isn't clear from what I'm writing, I'm having an wonderful time with this project. It doesn't hurt at all that I'm making this for my niece who is absolutely drooling over every step -- she would have been happy with a box that made noise and had a paper insert!

If anyone has questions about any of the steps I've taken building this, feel free to PM me with questions. I'm even willing to open my mad scientist lair on occasion for locals who need help with specific tasks along the way.

My results aren't as pretty as some, but I'm really happy with the results.
 
I'm looking for the vector diagram since I'm about to have 'free' access to a laser cutter/engraver.

(free other than buying materials and paying for the laser cutter :) )
 
Fixed some paint issues, and did some test fittings. Had some interesting issues getting the button and the red light to fit into their holes, looks like I need to drill them one size larger than I should have to. Weird.

Most current picture enclosed.

Senjak
 
severe painting issues.

if you use oil based sharpie pens, you might have extreme problems with clear coating causing the pen ink to run.

Not sure that I can sand off the paint without removing the numbers and other details.

Feh.

On the plus side, my niece was over and had a blast helping me remake the Farnsworth plate. We're not so happy with how the plate turned out; however, we going to keep working on them till we get them right!

My garage is getting cold!
 
Not really a lot of pictures today, as my Niece was taking and posting the pictures to her FB account.

Lessons learned today:


  1. Sharpie Paint pens work great for masking. Terrible for painting cracks. Even when dry will absorb clear coating liquid and flow.
  2. You can only remove paint plus clear coating so many times.
  3. Attach the plate to the 1/4 inch thick wood strip first. Then drill a small alignment/pilot hole. Then clamp both to the 1/2 inch thick wood strip. you will be much happier about the placement of the 3" hole.
  4. Etching takes longer than you might think. Etch speed depends on how much is exposed. Yesterday's deep etch came due to a very small surface area exposed.
  5. Scrap area around the 1/4 inch thick wood strip makes a great spacer for around a too deep Farnsworth lens.
  6. Sharpie paint pens make for some very interesting etch patterns.
  7. The wire attached to the item to be etched will get really, really, really hot.
 
This morning's lesson.

Scrape over sharpie induced mess with the brass brush. Then apply nail polish remover. Wipe clean.

Well mostly clean, the bits I wanted to leave behind stayed! Wow. Niece will be bouncing off the wall with excitement when she sees the results.

Senjak
 
Looks like a good job to me.
Question - THe speaker grill on the faceplate, was that done with prolonged etching process (Until it ate right through the entire brass), or did you drill/cut those out?
 
The speaker grill was done with prolonged etching. I may do some additional etching from the reverse side, or not for this face plate.

After cleaning up I'm *really* happy with the look of the lettering and the 'used in the field' look.

And this is just the plate for my niece's Farnsworth. I haven't started on the one for me yet.

Course I've told her that she is welcome to swap plates with me at a later time if she likes the look of one of the later plates. I've been very successful at getting her hooked on making stuff, and she's even starting to make noise about the next prop we tackle making *together*.

Her mom and dad just think it is cool. Her much younger brother is a grinch shade of green right now.
 
Some notes on etching with electricity.


  1. Surface area of exposed conductive surface greatly affects the speed of the etching.
  2. Higher concentration of Root Kill really makes a difference.
  3. Need to find a better way to transfer images, I'm having so-so luck with the transfer.
  4. Need to follow up on the thread that mentioned that Brother laser printers put the toner onto the media at a higher temp. Different laser may have different results.
  5. Sharpies oil based paint pens work pretty well, but not quite as well as laser toner. But I really like the effect on the material.
I hope folks are finding my adventures with building a Farnsworth interesting and useful.


Senjak
 
Mark-I is completed. We ended up taking some short cuts to get it done tonight -- the sound isn't installed; however, the rest of it looks great. We took it along to the TC Makers group to show off.

Senjak
 
Notes for the Mk-II.

  1. Better looking lens.
  2. Better pots to hold dials in place.
  3. Longer Etching time.
  4. Improve Etch mask transfer.
  5. Better offset from case.
  6. Smaller big drill hole.
  7. Larger red flasher hole.
  8. Keep the aged look.
  9. Look for better masking pens. Sharpie was only okay, not great.
  10. Cell phone ringing module to engage sound?
  11. External trigger for sound.
  12. Use sound module!
  13. Get a grinder.
  14. Replace belt sander.
  15. Get a real work bench!
That seems to be about it for my todo list.


Senjak
 
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