Unsticking epoxy glued parts?

[hotponyshoes]

So i have got a marine vhf antenna.
I got given this as the cable has been cut off.


I do have the proper connectors and a coupler so I could just fit those and cover with adhesive heatshrink but that's going to be bulky and ugly so I would rather get it apart and fit a new length of cable if possible.

It looks like the mast is fiberglass and the base is plastic. I think it's been stuck togeather with epoxy?


I did think about cutting it off at the glue line then removing the glued in bit with a dremel but there is a sharp taper on the mast section so the bit that needs to go back in will be a very sloppy fit.

I did a quick google and it looks like warm sulphuric acid will dissolve cured epoxy but I think that might also dissolve the plastic base. Along with my hands, the brush, the workbench etc.

I am currently thinking of slitting the plastic base with a dremel cutting disc and seeing if I can leaver it apart enough to break the bond?
Any better ideas?

 

[waddycall]

You could try warming it up and pulling/twisting just to see. I’ve separated kayak paddles from the shafts that way. I think they may be epoxied on.

 

[hotponyshoes]

I have got an adjustable hot air gun so I might give that a go!

 

[waddycall]

I have got an adjustable hot air gun so I might give that a go!

That’s what I used. Keep a close eye on it.

 

[Lazurus]

Acetone often works?

 

[Cobbler]

I’ve separated some epoxied jewellery that my wife made with heat, but I think the plastic would go at a lower temperature than the glue.

 

[slim_boy_fat]

Acetone often works?

Doesn't it melt certain plastic types, though?

 

[hotponyshoes]

I have got enough acetone to submerge it, I have had some types of plastic turn to mush using it though

 

[MCKDAVID]

+1 for gently heating, go slow and work the heat evenly all round it.

 

[hotponyshoes]

What sort of temp are we thinking?
I could set the hot air gun up with a shroud and heat all around it easily enough.
70deg?

 

[Screwdriver]

Gentle warming and a firm grip would be my first goto. Getting a good grip on the antenna without damaging it (!) is tricky and will require some set-up time, wooden clamp with rubber insert for example.

Boiling in water will not overheat the plastic and can bring it up to temperature without melting it. Any chemical that will destroy the epoxy will also attack the fibreglass. A drop or two of acetone carefully applied only to the join might help.

<edit> something like this. Bung it in a vice.

 

[MCKDAVID]

if your heat gun is adjustable, start low and build up, you're only trying to soften the epoxy not burn it out, so shouldn't need to go too hot, 70° would probably be a good starting point. Obviously you don't want to go so hot that you burn or damage the base fibre glass / plastic.. You'll know soon enough if it's working or not.

 

[hotponyshoes]

Gentle warming and a firm grip would be my first goto. Getting a good grip on the antenna without damaging it (!) is tricky and will require some set-up time, wooden clamp with rubber insert for example.

Boiling in water will not overheat the plastic and can bring it up to temperature without melting it. Any chemical that will destroy the epoxy will also attack the fibreglass. A drop or two of acetone carefully applied only to the join might help.

<edit> something like this. Bung it in a vice.

I can do it by hand I think.
I have ample length and a good strong grip.

 

[Screwdriver]

I can do it by hand I think.
I have ample length and a good strong grip.

Well, it's going to be hot don't forget

 

[waddycall]

Just wave your hot air gun around until it’s v warm all over. Dont stay on one spot too long and it should be fine.

 

[waddycall]

....and wear gloves

 

[hotponyshoes]

The actual antenna part has a decent taper so I cant clamp it sensibly as I will just be pulling it out of whatever i clamp it with. Its 5' long and I dont think fibreglass conducts heat that well so I should be able to hold it. Maybe.

 

[hotponyshoes]

IT'S WORKED!!

Hot air gun with one of those heat shrink reflectors on it. Set to 70degC and nothing so tried 90.
I think it's just softened the plastic enough to allow it to deform enough for the glue to pull out (that's not gone soft at all)

 

[MCKDAVID]

nice one

 

[pedrobedro]

Result ! Repair and reuse I like to see.