Loosening a thread locker - ODU(LEMO) connector disassembly  - Page 1
Forum section: electronics / repair

author: BBBbbb
author_rank: Unknown
timestamp: August 01, 2017, 06:50:07 pm
content: Does anyone have any advice on how to loosen up thread locker. My first and only idea would be heat, but is there any other way?I'm trying to disassemble an ODU (LEMO) connector to fix an intermittent contact issue with one of the pins (out of 19). I've tried to unscrew it but I started to wear it out, so I stopped until I make sure how to proceed.By specs the connector is FGG.2B.319 series by LEMO, but I'd have to change both cable and panel connector then, since I could find on stock at stores online only the ones with the opposite gender of the ones I have. Lemo's not cheap, and changing both would end up more than 200USD (for a connector!), that's why I'm thinking it twice before increasing brute force.Assembly instructions attached.

author: elecman14
author_rank: Unknown
timestamp: August 01, 2017, 06:59:04 pm
content: You could try soaking it in acetone or another solvent. The problem with this approach is that it might not penetrate the threads. Other than that heat and torque.

author: BBBbbb
author_rank: Unknown
timestamp: August 01, 2017, 07:08:29 pm
content: Quote from: elecman14 on August 01, 2017, 06:59:04 pmIt's supposed to be watertight so I doubt any liquid solvent could get through.

author: elecman14
author_rank: Unknown
timestamp: August 01, 2017, 07:28:16 pm
content: My bad, I have no idea about those connectors...looks like you are stuck with heating them.... Good luck

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: August 01, 2017, 08:37:37 pm
content: Some threadlocks dissolve in methylated spirit (industrial alcohol) This would be safer than acetone which damages some plastics.Other than that, controlled heating with the ol' Atten 858 is probably the way to go. Or warm water, can always dry out afterwards. It's kinda rare for any decent plastic to not stand 100C.

author: GreyWoolfe
author_rank: Unknown
timestamp: August 02, 2017, 01:33:57 am
content: I have used heat in the past, including a propane torch on non plastic parts.

author: amyk
author_rank: Super Contributor
timestamp: August 02, 2017, 01:58:36 am
content: Impact wrench?

author: ijchan223
author_rank: Contributor
timestamp: August 02, 2017, 02:16:41 am
content: apply heat and the proper size wrench. but to be safe i would buy a spare connector.

author: Armadillo
author_rank: Super Contributor
timestamp: August 02, 2017, 07:50:05 am
content: Turn anti-clockwise!?If you have used, thread locker like 262 Red, then I think cut at the nearest wire.The rationale behind this is that you will likely scratch and leave indelible marks behind the connector surface in the brute attempts and since this is likely a medical instrument and for such clean microbial environment is not going to be acceptable, let the institution pay for the new connector.

author: BBBbbb
author_rank: Unknown
timestamp: August 08, 2017, 03:10:57 pm
content: I bit late on a follow up, but a couple of days ago I was manually shredding some bank account statements with some scissors I found lying around on the desk. The handle broke in the process and I did sufficient damage to my hand to keep me out of any somewhat heavy manual labor. Yesterday I finally got the job done.OK, so heat and torque did it, without a problem. Seems they filled up the connector with the glue gun prior to closing, so heat was a must obviously, I doubt the thread locker was to blame in the first place.Everything is working now.Quote from: Armadillo on August 02, 2017, 07:50:05 amI'm the institution, well I am the owner now. It's a part of the imaging subsystem (microscope with a camera, control box), of a lot bigger device that is EoL, that I'd like to rework for my desk use for inspection and soldering. I will have to have some holder made and if this connector proved troublesome I would have given up since I would be approaching the cost of some simple commercial solutions..

author: HighVoltage
author_rank: Super Contributor
timestamp: August 08, 2017, 07:17:38 pm
content: LEMO in fact is using a thread lock glue and the only solution I have found is bring local hat to the thread.Also, one must use perfectly fitting wrenches with close to zero play, to apply the torque correctly.

author: Smith
author_rank: Frequent Contributor
timestamp: August 11, 2017, 06:18:05 pm
content: Have you asked LEMO? They have been verry helpfull in the past.

author: BBBbbb
author_rank: Unknown
timestamp: August 12, 2017, 11:49:09 am
content: Quote from: Smith on August 11, 2017, 06:18:05 pmWell, there's not much to contact them for. Assembly instructions on both Lemo and ODU websites are abundant, it was more of a question of loosening the tread locker - at least that is what I thought, but it turns out the tread locker was a medium strength one (probably loctite 243 as pre assy instructions). The problem was that it was filled with a glue gun (not in the LEMO instructions) and once it softened from the heat it was quite easy to take it apart.