Conformal coating - Page 1
Forum section: electronics / beginners

author: cybermaus
author_rank: Frequent Contributor
timestamp: December 15, 2023, 07:18:55 am
content: What to best use. Cheap, easily available, robust.I could just order some, but well, I'd still have to wait a few days. And I am frugal.Even if not made-to-purpose, can I just use any acrylic clearcoat spray-paint, or should I really better not.and as I may need to consider compatibilities, if I am fixing a board made in the late 90s, what stuff is most likely to have been used?Wikipedia lists acrylic, urethane, silicone, and varnish as options.Thanks

author: LinuxHata
author_rank: Frequent Contributor
timestamp: December 15, 2023, 08:32:58 am
content: 1B73.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: December 15, 2023, 09:51:24 am
content: https://mgchemicals.com/category/conformal-coatings/I'd try some poly from the local hardware store.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: December 15, 2023, 10:16:48 am
content: Conformal coating spray from the main distributors is very expensive. I still have an old can of aerosol spray that cost 1/4 of the cost of the lowest priced spray from Mouser, it came from a now closed high street chain in the UK (Maplin). Beware that aerosol cans are restricted in terms of shipping overseas... In Europe, look for these at reasonable prices:Kontakt-Chemie 74309-AH Plastik 70 PCB LacquerElectrolube AFA200 Aromatic Free Acrylic Conformal CoatingThe Electrolube spray has industry standard approval and is not much more money than clear acrylic spray from a hardware store, although it's probably very similar.SJ

author: jpanhalt
author_rank: Super Contributor
timestamp: December 15, 2023, 10:38:46 am
content: The branded conformal coating I have is acrylic. One might ask, why do you need solvent resistance? In fact, if you ever need to repair, poor solvent resistance might be an advantage. Acrylic has a leg up on repair, namely you can solder through it.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: December 15, 2023, 06:12:33 pm
content: Quote from: jpanhalt on December 15, 2023, 10:38:46 amBecause common chemicals in the environment would constantly attack the coating. Read that as "poor chemical resistance"

author: jpanhalt
author_rank: Super Contributor
timestamp: December 15, 2023, 08:34:16 pm
content: Please be more specific with data. What "common chemicals" in the environment are present at sufficient concentrations in the air to affect such standard acrylic conformal coatings. My acrylic version is MG branded. To me, the potential need to do a repair/modification (as a hobbyist) is a more important consideration.

author: rdl
author_rank: Super Contributor
timestamp: December 16, 2023, 02:37:00 pm
content: Why do you think you need a conformal coating? It is not commonly used.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: December 16, 2023, 05:40:46 pm
content: Quote from: jpanhalt on December 15, 2023, 08:34:16 pmBug spray, rubbing alcohol, acid rain, smog, pollen

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: December 16, 2023, 06:07:45 pm
content: “Why do you think you need a conformal coating? It is not commonly used.”I use it on home made circuit boards (bare copper tracks) that would otherwise tarnish. I also use it on boards that are used outdoors to avoid condensation causing problems. Acrylic spray is fine for this job and doesn’t cause any problems for reworking.Commercially it is also used on boards In intrinsically safe equipment, generally using a tougher coating than acrylic… I used to repair boards that were epoxy coated, that took some removing.SJ

author: cybermaus
author_rank: Frequent Contributor
timestamp: December 16, 2023, 07:04:47 pm
content: Quote from: rdl on December 16, 2023, 02:37:00 pmNot sure why you would say that. In the hobby world maybe, but even as a hobbyist I work on plenty of factory made stuff that is coated.Of course, it is a hassle to rework on, which may explain with the non-use in places where you often have to rework (hobbyist and professional prototyping alike)But as soon as it is meant for outdoor or even consumer bathroom, and it is the barest of quality (so not china or dollar store junk) it is coated. Even more so for industrial environments, which is where this board goes back into... well, into a old industrial CNC in my workshop. My workshop is also an industrial environment right? It sure gets dirty enough.Anyway, I put on 3 layers of plain acrylic clear coat. It does not beep anymore on my multimeter continuity test, so it is probably fine.For the rest, I'll order some of the Kontakt-Chemie 74309-AH Plastik 70 PCB Lacquer and Electrolube AFA200 Aromatic Free Acrylic Conformal Coating mentioned above, next time I order stuff.