Removing old silicone

[fiestaMojo]

I am changing my deck mounted running lights; the old lights were "bedded" with about 1/2" of silicone. I've managed to get a lot of it off, but the last bit doesn't want to go. What is the best way to get this off? I've tried vinegar, IPA and scraping. . .

[brak]

No chemical will help.
My own process for removing silicone is:
1) using a chisel on the largest amounts
2) using a knife (I have an old kitchen "steak" type knife with a relatively flexible blade) on what remains
3) using sandpaper on the surface to remove the "residue" (check by wiping some water on it - if water no longer "beads" or "pools" - silicone is finally gone).

While doing that, I keep cursing the PO and whoever was the first dumass that thought up the idea of using silicone as a sealant on a boat.

(Just had to rebed the dorade boxes and, you guessed it, more silicone)

[Sailormann]

Acetone helps

[brak]

Originally Posted by Sailormann

Acetone helps

I used to think that

That said, it does help in some cases if silicone is applied over something like paint that can be dissolved by acetone - in which case silicone may somewhat come off with underlying material. This does not generally help on FRP.

[noelex77]

Supprisingly WD 40 seems to work and is safe on most (all?) surfaces.

[brak]

Originally Posted by noelex77

Supprisingly WD 40 seems to work and is safe on most (all?) surfaces.

Curious. I would guess it also breaks the bond between silicone and the surface - but I'd like to try it.

[Sailormann]

That said, it does help in some cases if silicone is applied over something like paint that can be dissolved by acetone - in which case silicone may somewhat come off with underlying material. This does not generally help on FRP.

Geez - guess the sink in my head must have been painted

[sailingdog]

Unfortunately, the oil from the silicone is a pernicious contaminant on fiberglass and very difficult to get rid of. If you think you've gotten rid of it all—an easy way to check is to pour water over the surface.... if it beads at all, instead of wetting the surface, you failed.

[fiestaMojo]

Thanks all for the input, when it stops raining I'll be back at it. . .

[sawingknots]

is it silicone or 5200?just a lot of elbow grease and liquid dish soap seems about the only answer I know of