Removing conformal coating for PCB re-work - Page 1
Forum section: electronics / projects

author: rossmoffett
author_rank: Regular Contributor
timestamp: November 29, 2010, 04:30:43 pm
content: I have some boards with a conformal coating that need parts swapped - I've got that part done, but after I need to re-coat. I bought some products from Techspray. A conformal coating remover "pen" and a spray-can of conformal coating. The spray-on looks awful over the top of the existing conformal coating, there are loose droplets everywhere and foggy areas. I've tried stripping the old coating with the pen so I can do an entirely new coat, but it's very slow-going. I tried acetone, and it helps but still won't strip the stuff off on its own. It seems like some kind of silicone material.Any ideas on how to effectively remove this stuff, so I can spray a new coating entirely?

author: DJPhil
author_rank: Frequent Contributor
timestamp: November 30, 2010, 01:12:56 am
content: It's super time consuming, but you can scrape it off with some dentist picks. I recommend working under UV light as it should make the coating glow so you can see your work more easily. I found it helps to heat the board slightly, just enough to take advantage of the slightly softer coating to peel up larger sections. The bits around components take the most work. If you're after nice looking results I'm not sure anything else will really work. It goes fairly quick with some practice.If there's a faster chemical method that does a thorough job without harming the parts that'd be awesome. I've got a half dozen industrial lighting ballasts I'd love to strip the parts from.

author: rossmoffett
author_rank: Regular Contributor
timestamp: November 30, 2010, 10:12:36 am
content: The Acetone softened up the coating significantly so that it was easier to scrape, soaked over Thanksgiving weekend (5 days almost) and didn't even dissolve the silkscreen. I was just hoping for something faster or more effective. I bet the conformal coating removal pen has acetone or the like inside.

author: DJPhil
author_rank: Frequent Contributor
timestamp: November 30, 2010, 11:34:43 am
content: Good call, I'll give it a shot on my boards as soon as I can arrange a spot indoors where nothing will get knocked over for a few days.The weather here just started to hit full on winter, so I've got to square away an indoor safe lab area for etching anyhow.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 30, 2010, 01:58:50 pm
content: Quote from: rossmoffett on November 29, 2010, 04:30:43 pmany pictures of the items?

author: TechGuy
author_rank: Regular Contributor
timestamp: November 30, 2010, 09:57:29 pm
content: Try methyl ethyl ketone MEK

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: December 01, 2010, 01:53:49 pm
content: Be careful with MEK. I don't know for sure, but I think it will dissolve some plastic components, and probably the plastic sleeves that cover electrolytic caps. Test it on some junk parts first.

author: TheWelly888
author_rank: Frequent Contributor
timestamp: December 01, 2010, 04:23:37 pm
content: ^^^MEK WILL dissolve plastic parts - modelmakers use small amounts of it to weld plastic parts together. And it stinks so use in a well ventilated room. Also take care not to knock the bottle over or you will have a right mess on your bench!