Removing potting compound to allow repair - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: January 24, 2022, 03:16:55 am
content: I've got a chinesium DC-DC converter 12V to 18V 8A.It's one of these:https://www.ebay.co.uk/itm/165145242820and is potted with a very solid black potting compound.This the second replacement that I've purchased because the originals failed (after > 1year).Next time if it fails I would like to try to repair, but removing the potting is problematic.Any suggestions on how to remove the potting compound without damaging what's inside...ThanksDavid

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 24, 2022, 08:14:30 am
content: On another post, someone suggested soaking in acetone rather then IPAI have not tried it myself though.Also, if you already have two broken ones, why wait for the 3rd one to fail. Open one preemptively.Though of course the suggestion of chemicals into the environments is a valid one.What is more circular: Using chemicals to fix one, or allow the Chinese to waste resources to build yet another one?

author: jonpaul
author_rank: Super Contributor
timestamp: January 24, 2022, 08:58:14 am
content: Chinese wall PSU are the cheapest , poor specs, bad reliabilitySurprised they last a year.Depotting is difficult, may be hazardous and the units are not useable afterwards.Suggest to buy a quality PSU from a supplier with a warranty and support and no0t Chinese junkJon

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 24, 2022, 09:42:29 am
content: Basically there are 2 that could help: gasoline or butanone aka mek.

author: ESTechnical
author_rank: Contributor
timestamp: January 24, 2022, 09:59:33 am
content: Hi,We have had some success with removing potting with paint strippers that contain dichloromethane or methyl ethyl ketone. Try Paint Panther or Power Strip. Also, silicone remover gel contains MEK, so that might work too.Be aware that this will also strip soft PVC cable insulation, the epoxy coating of some capacitors etc. Most SMT parts survive completely unscathed but dipped capacitors will probably turn gooey!An ultrasound cleaner and acetone (outside!) may also help clean it up.Good luck!

author: Martin Miranda
author_rank: Regular Contributor
timestamp: January 24, 2022, 10:04:32 am
content: heat it with a hot air station. then dig out the epoxy potting. it's slow but just options to skin a cat.

author: perdrix
author_rank: Frequent Contributor
timestamp: January 24, 2022, 02:16:41 pm
content: Quote from: jonpaul on January 24, 2022, 08:58:14 amWell if I could find a good one with that specification ... Pointers gratefully accepted.

author: ESTechnical
author_rank: Contributor
timestamp: January 24, 2022, 03:21:20 pm
content: https://www.ebay.co.uk/itm/174696916905Is this more suitable? Certainly an easier task to fix if it breaks haha

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 24, 2022, 05:10:28 pm
content: Personally, I really rather have a potted and encased one if I were to mount it in my vehicleThough one that does not break, so the 20 Amps may be a good idea.Which reminds me: You are giving the 8Amp one proper cooling? Its not like you buy one with integrated heat sink, and then stuff it between the padding of two seats without air or metal? If you run them hot they will indeed no last long. Solid connection to metal on one side, open air on the other.

author: perdrix
author_rank: Frequent Contributor
timestamp: January 25, 2022, 10:55:42 am
content: In real use for my application the current draw is below 1A most of the time with very occasional peaks of up to 5A for short durations, so 8A rating seems reasonable.The module always ran cool.D.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 26, 2022, 04:26:14 pm
content: Do hot air gun at least 153oC and immediately slowly chipping away the glassed compound. It'd be time consuming true, Imho no way else