# I need to turn clear 2-part epoxy opaque **URL:** \ **Category:** Factual Questions\ **Created:** [March 21, 2025, 10:07pm UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934 "2025-03-21T22:07:02Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 23, 2025, 12:02am UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/21 "2025-03-23T00:02:39Z")
> [@jnglmassiv](#): > > Because it’s safe, inert for electronics and epoxy curing, and black as night. It doesn’t stain or dye and handling powder is familiar to most people. What makes you think a highly conductive powder is inert for electronics? > [@Kedikat](#): > > If you are potting electronics, make sure the colour additive will not create conductivity issues. This. Toner powder is a _terrible_ idea. Buy actual electronic potting compound and be done with this homebrew silliness. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [March 23, 2025, 1:29am UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/22 "2025-03-23T01:29:44Z")
> [@LSLGuy](#): > > What makes you think a highly conductive powder is inert for electronics? I said to try toner because, among other reasons, one of its chief design characteristics is the high electrical resistance needed for electrostatic transfer. I’ve seen circuit boards packed with the stuff and it’s a complete PITA but not because it’s shorting. It builds up and cakes hard and then flies off in chips. I also used to service equipment at a factory making metal wool products, mostly household dishwashing steel wool pads, some familiar brands with blue soap, but other things like bronze wool for rodent-proofing caulks and rubber: rats don’t like gnawing the long lasting bronze. Now THAT place was a nightmare for conductive fibers getting into everything. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 23, 2025, 1:24pm UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/23 "2025-03-23T13:24:14Z")
I bow to your superior experience. Thanks for the corfection. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [March 23, 2025, 6:27pm UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/24 "2025-03-23T18:27:12Z")
I am going to second @Francis_Vaughan and recommend a proper potting compound made for this purpose. If the board is going to see any significant temperature swings you want a compound with a coefficient of thermal expansion that matches the PC board material or else you risk breaking connections on the board, especially if there are any SMD devices. ---
**Author:** ![Cartooniverse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cartooniverse/32/3084_2.png) [@Cartooniverse](https://boards.straightdope.com/u/Cartooniverse)\ **Post date:** [March 27, 2025, 1:24am UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/25 "2025-03-27T01:24:45Z")
Good thinkin’ The device will be used in all temperatures that people work in, from 110º to -20º f. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [March 27, 2025, 3:28am UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/26 "2025-03-27T03:28:10Z")
You’re probably OK if you stick with a product that specifically says it is meant for use on printed circuit boards. The one that @Francis_Vaughan suggested is nice in that it is (1) specified for PC board protection and (2) is relatively inexpensive and available in small quantities. ---
**Author:** ![Cartooniverse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cartooniverse/32/3084_2.png) [@Cartooniverse](https://boards.straightdope.com/u/Cartooniverse)\ **Post date:** [March 27, 2025, 7:51pm UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/27 "2025-03-27T19:51:32Z")
Well,Marv, I am leaning in that direction. ---
**Author:** ![Hampshire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hampshire/32/4887_2.png) [@Hampshire](https://boards.straightdope.com/u/Hampshire)\ **Post date:** [April 1, 2025, 9:27pm UTC](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934/28 "2025-04-01T21:27:03Z")
Would something organic as simple as flour work? [Previous page](https://boards.straightdope.com/t/i-need-to-turn-clear-2-part-epoxy-opaque/1015934.md?page=1)