Vacuum Tube Lights: Urethane Coated Plate Cap

With a generous dollop of JB Plastic Bonder left over from a set of Bafang brake sensor magnets, I tried coating the ersatz plate cap of a triode tube:

Triode - urethane coated plate cap
Triode – urethane coated plate cap

That’s the result after leaving it hanging upside-down while it cured to push all the drips to the top.

For comparison, the uncoated cap back in the day:

Triode - plate cap plug
Triode – plate cap plug

Seeing as how the urethane is an adhesive, not a coating, I’d say it looks about as bad as expected.

As with all 3D printed things, one must embrace imperfections and striations, rather than endlessly strive for perfection.

Now, if I had a resin printer …

4 thoughts on “Vacuum Tube Lights: Urethane Coated Plate Cap

  1. I got a resin printer. An Elegoo Mars II Pro. It pretty much works right out of the box. It does have a whole new set of issues to deal with, though. Supports and required voids are brand new things to consider. Three inch thick opaque resin won’t ever cure so all you can really print is a shell of your object. I haven’t used it yet, but I suppose semi-transparent resign might be OK for thick solid regions. Supports are required to make sure that your print is bonded to the build plate more than the transparent film where the printing takes place. It’s an art and a science. Resin doesn’t produce strong objects. Also, messy. But the detail is fantastic.

    1. A friend has one and it seems like the perfect way to make LED light pipes and shapes for mold positives. Anything structural, not so much.

      I looked at them about a year ago, back when isopropyl alcohol ran well over fifty bucks a gallon, and decided I lacked that much of an itch to scratch.

      1. ABS is a way to go for smooth finish. Print at 150 or 200um layer, put the print on a sheet of glass or other acetone resistant material. Secure a kitchen paper towel sheet or two in the bottom of a mason jar, wet with enough acetone to almost saturate the towel but not so much it will drip and cover the print with an overturned jar. Check progress every few minutes and vary the amount of acetone.
        Prints take long time to evaporate the acetone back but they do look pretty :)
        It won’t work for overhangs and critical tolerance parts.

        1. I gave up on ABS when the Thing-O-Matic reached end-o-life, started with PLA in the M2, switched to PETG, and never looked back. IMO, the real way to put a nice finish on a small artsy object involves a resin printer, but that’s a whole ‘nother lifestyle.

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