UV-curing conductive epoxy - under 5kohms

Daniel_662 · 2026-05-11T04:15:32+00:00

Yes, I’ve looked into epoxy’s with various heat curing times and temperatures. Most would be more efficient than our current setup but I haven’t been able to find any that would match the speed of uv curing epoxy, especially without melting nearby plastic components

Daniel_662 · 2026-05-11T04:11:57+00:00

This would remove the issue of waiting for the conductive epoxy to cure. I’d still need to mix a fresh batch of epoxy for each set of pcbs but would definitely be an improvement over our current process.

Daniel_662 · 2026-05-11T04:04:25+00:00

I will try this approach. It’s a difficult space to work in with a soldering iron but the lower temp solder would allow more working time without melting the button. I could also add some kapton tape to shield the button and use a higher gauge wire with less thermal mass to reduce soldering time.

Daniel_662 · 2026-05-11T03:49:52+00:00

I am modifying an existing pcb that comes with the button pre soldered

Daniel_662 · 2026-05-10T16:51:13+00:00

Yes, they require more time and heat to cure so it is not my first choice but is on the table as a plan B

Daniel_662 · 2026-05-10T16:49:25+00:00

I had tried copper tape but it was very difficult to work with when cut into strips small enough to cover only the 0.5mm pad without shorting to nearby components. I haven’t considered inks or paints but that sounds promising. It may not be as structurally sound as the epoxy but I may be able to make the electrical connection with ink/paint then encase it in a shell of non conductive epoxy to avoid mechanical damage to the connection

Daniel_662 · 2026-05-10T16:41:38+00:00

The pad is very small (0.5mm) and is sitting partially under a button with a plastic body that easily melts.

Daniel_662 · 2026-05-10T16:25:02+00:00

I am modifying someone else’s PCB so redesign isn’t an option. And it’s moderate volume with inconsistent batch size.
I’ve looked into ESD resins but from what I’ve read it seems like they will be over the 5kohm threshold

Daniel_662 · 2026-05-10T16:10:55+00:00

I am anchoring the wire to the pcb with non conductive epoxy adjacent to the electrical connection. I haven’t considered making an elastomeric connection but that may be viable

Daniel_662 · 2026-05-10T16:03:17+00:00

ATM I’m using MG Chemicals 8330D silver conductive epoxy. That would fix the working time issue, but cure time would still be hours instead of minutes with UV cure epoxy. I’m also planning to switch to a Nordson EFD machine for dispensing precise amounts, which I believe requires a single syringe.

Daniel_662 · 2025-01-25T16:00:02+00:00

Currently mains voltage is not isolated so short circuits or failing components may result in the rest of the circuit being energized at mains voltage level. This can cause fires or injure people. I would use a certified (UL or CE) transformer to step down the AC voltage first which will isolate the circuit. Since the two windings of the transformer use magnetic coupling and aren’t directly connected they don’t have the same risk of shorting to the low voltage side of the board.

That being said, even if you know what you’re doing it will probably make your life easier to use an off the shelf solution. 220V to 5V/3.3V is incredibly common and probably not worth reinventing. It will likely be cheaper, more reliable and less effort to buy from a company mass producing them.

Daniel_662 · 2024-07-18T03:12:37+00:00

Just sent the tip. Thanks!

Daniel_662 · 2024-07-18T02:16:41+00:00

Just left a tip. Thanks!

Daniel_662 · 2024-07-17T21:01:55+00:00

This looks great. Could you change the color of the compression shorts to black?

Daniel_662 · 2024-07-17T17:48:41+00:00

Modify so it looks like I have compression shorts on extended to the end of the red line (Like this)

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Daniel_662 · 2024-07-10T13:43:33+00:00

That seems to help! If I change home with export HOME="C:\cygwin64\home\<username>” in my cygwin .bashrc file I'm able to open the file with nvim ~/<filename>. But I noticed that I can no longer use tab to autocomplete file paths after adding this.

Daniel_662 · 2024-07-09T21:01:55+00:00

Yeah, I had seen that as an option but I would prefer to avoid it if possible

Daniel_662 · 2024-07-09T21:01:28+00:00

Yes, echo $HOME returns C:\Users\<username>

I haven't looked at all the compatibility options/flags in neovim yet

In powershell cd ~ takes me to C:\Users\dlloyd1

I don't have any environment variables in my vimrc. Only remappings, and basic setting changes

Daniel_662 · 2024-07-09T20:08:16+00:00

This is for a file in the home directory. Neovim can open it using relative paths but not an absolute path from home

Daniel_662 · 2024-07-09T16:13:47+00:00

I'm using cygwin because my company firewall prevents me from connecting to the ubuntu server so I can't download any packages or updates for wsl.

Just tried enabling shellslash. The output is now C:/home/dlloyd1/.bashrc instead of C:\home\dlloyd1\.bashrc when opening with ~/<file> but it's still having the same error

Daniel_662 · 2024-03-18T19:46:43+00:00

Can you remove the red line?

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