Using quite a bit of 2-part epoxy. Not many gallons. More like…2 cups of each, or whatever ratio the bottles tell me to use. I’ve used this stuff in the past, works great, sets up in 24 hours like rock. ( Just cannot remember the ratio but I’m not worried. )
Here’s the issue. I need it to be opaque when it sets up. It’s being drizzled over electronic wiring. Doesn’t have to be black, just has to stop prying eyes from seeing the small circuit buried within.
Using something thicker/ goopier has proven to be just a hella mess. Something like black silicone caulking? Atrociously hard to manage. Using it in this context reminds me of Bill Murray in “Ghostbusters” when he gets the slime all over his hands in the Public Library, and in trying to flick it off, gets it on his face, etc.
Thoughts on what I can stir into the 2-part mix as I’m mixing it to turn it opaque? I actually thought of using ground pepper, but somehow I think that’s not a good idea. Or, is it?
What could I put in that wouldn’t mess with the epoxy and would do the trick?
You might consider a made for purpose epoxy potting compound. Depends how price sensitive and how critical the application is.
So long as your additives are chemically neutral and your epoxy is properly mixed and cured you will probably be fine with a home grown mix. But made for purpose compounds will be a known good product that won’t cause long term problems. You likely don’t want it corroding the circuit over the years.
I would try carbon black, or talcum powder, etc., for artistic purposes, but for electronics they make special electronics-grade potting compound, stable and with known properties, as said.
Waaay back (90s…maybe late 80s…I forget) I was doing temp work in a lawyer’s office. The photocopy machine had a bottle of toner it would use. One of the secretaries went to replace it. She opened the bottle in the storeroom and carried it across the office. For some reason, she dropped it. That shit poofed out everywhere and stuck to everything. An almighty mess.
They told me to clean it up. I quit on the spot. I was paid basically nothing for a summer job (like $3.50/hour). No way was I cleaning that mess up. Wasn’t something I did (if I was responsible I would have cleaned it up).
Thomas Johnson Antique Furniture Restoration is a YouTube channel. A very down-to-earth guy in Maine, and very attentive to historical accuracy. But once in a while, in parts that can’t be repaired otherwise like bad breaks with missing bits in the join, he uses epoxy to make sure there are no voids. He usually has to color it, and he uses dye powders that he has in little canisters.
There have probably been better answers to OP’s question already, but this is factual, and it is also a chance to plug one of my favorite channels.
I used to service equipment at toner factory. And not a cartridge filling op, they mixed black and hot plastic(?) by the ton. I remember watching it it roll off a machine onto a conveyor like a long loaf of bread dough or taffy but as black as can be. After it cools, they crush it into the fine powder we all know & love.
You pretty much start getting it on you when you pull into the parking lot. It in your nose, the corners if your eyes, ears, between your toes, all of it. They say it’s pretty inert but I was always happy to get out of there.
I am loving these replies.
The corrosion aspect does concern me, so I’ll tap into the link up there and use a dye specifically designed to be inert in epoxy.
Best just get some resin dye or pigment - it’s cheap on eBay and other places and a little goes a long way. The mica-based decorative pigments can tend to settle out if you are using resin with low viscosity, but finely-ground pigments and liquid resin dyes won’t.
If you want to use some household stuff you have to hand, this guy has done quite a bit of experimentation on that:
If you’re potting electronics, it’s probably worth considering whether your pigment might be conductive, so I wouldn’t use carbon for example.