How do I remove the "glue"?

[gmclam]

I am repairing a PSR-500 where I need to remove the RF shield near the BNC antenna connector. I have all the desoldering tools, so that is no problem. However, they've now added some sort of brown "glue" on top of several of the solder joints.

Has anyone run into this before? What is the best method of removing the "glue" so I can get to the solder?

Not sure what GRE is trying to prove with this. It makes a repair that would have taken less than 30 minutes now into more like a nightmare.

 

[gewecke]

You should be able to remove it with a heat gun, but be careful not to melt components. Use a Q tip to wick up the glue when its soft. :wink: 73, n9zas

 

[gmclam]

I don't think it is safe to use heat. Some of this is virtually on top of capacitors. The brown glue looks to be some sort of epoxy. Certainly the repair shops know a quick & safe way to remove.

 

[gewecke]

I don't think it is safe to use heat. Some of this is virtually on top of capacitors. The brown glue looks to be some sort of epoxy. Certainly the repair shops know a quick & safe way to remove.

Unless they're using something top secret or rubber, a little heat or sometimes solvent has always softened the glue for me. I'm lucky enough to have my own rework bench. .
73, n9zas

 

[ScannerSK]

If it is hard like epoxy you may be able to chip it off the top of the solder with the edge of a sharp flat/slotted screwdriver.

Shawn

 

[discombobulated]

If it is indeed a cement type "glue" I have ran into this with RC parts. They use it on antenna connections to keep them from coming apart. I have slowly removed it with an an xacto knife before.

Sent from my Nexus 5 using Tapatalk

 

[Voyager]

If it is indeed a cement type "glue" I have ran into this with RC parts. They use it on antenna connections to keep them from coming apart. I have slowly removed it with an an xacto knife before.

No - they use it to comply with FCC restrictions to components that could be altered to receive the cellular bands.

Odds are unless you have some really specialized solvents, you won't get access (which is the FCC's intent).

 

[gewecke]

I've removed the epoxy and pot wax from many pieces of gear over the years, and there's no special formula to lock down components that the fcc requires. Its more of a manufacturer issue than anything else. I've used alchohol, paint thinner, heat, a plastic tool, even nail polish remover. There's no real mystery involved. :wink: 73, n9zas

 

[gmclam]

Epoxy over solder joints

Odds are unless you have some really specialized solvents, you won't get access (which is the FCC's intent).

Thanks for your answer. I got access but I am sure there's a better method to remove it used by repair shops that hasn't been posted yet.

The problem in my case is that the connection from the antenna BNC to the PCB is a solid "wire". No place for it to flex, which is what happens normally when you're using a rubber ducky antenna. Over time, something has to give.

Earlier scanners had the same problem but not the RF shielding. I like the shielding, but the epoxy/etc is too much.

 

[gmclam]

I've used alchohol, paint thinner, heat, a plastic tool, even nail polish remover.

Alcohol had no effect. Heat must be directed to a narrow beam to avoid damaging components (some of the epoxy was on top of electrolytic caps as well). A tool to chip might work, but would take too long (and tough to use in the tight places). A metal file is a better choice, but not ideal either. Nail polish remover is usually acetone based. I'd rather not use that near metal as I just want to remove the epoxy (a desoldering iron can remove the solder). Thanks

 

[Voyager]

I've removed the epoxy and pot wax from many pieces of gear over the years, and there's no special formula to lock down components that the fcc requires. Its more of a manufacturer issue than anything else. I've used alchohol, paint thinner, heat, a plastic tool, even nail polish remover. There's no real mystery involved. :wink: 73, n9zas

Comparing epoxy to wax is like comparing a WV to a Ferrari. Wax is trivial. That said, what did you use on the epoxy?

Thanks for your answer. I got access but I am sure there's a better method to remove it used by repair shops that hasn't been posted yet.

If a repair involves those components, they just replace the board.

 

[gewecke]

Comparing epoxy to wax is like comparing a WV to a Ferrari. Wax is trivial. That said, what did you use on the epoxy?

On a timer pcb from a clothes dryer which had epoxy or something similar I used some caustic cleaner which softened the epoxy enough to pick it off the board, but resulted in some nasty fumes, but it worked. 73, n9zas



If a repair involves those components, they just replace the board.[/QUOTE]

 

[mancow]

You need a hot air rework station. There is a certain temp that it releases and will peel off. I want to say it's 120c but I can't recall right now.