Softening or removing silicon sealant

[feetup]

There are two decklights on a boat I recently bought set flush into the deck and held with sealant. The previous owner has attempted to seal them with what looks like an entire tube of silicon. The lights themselves appear to be of 3/8 to 1/2 inch plexiglass or lexan with about 1/8 inch of space around the perimeter for sealant and about a 1/2 inch lip under to support them. The question I have is this...How do I remove the silicon, and loosen the plexiglass so that I may re-seal properly, without destroying all and sunder?
Is there anything that will soften silicon? Could I use slow, increasing pressure from underneath till they pop? Heat?
Gratefull for any help.

Feetup

[cardiacpaul]

razor blade & elbow grease.

[sailingdog]

And lots of the latter..

BTW, using brute force is generally a really bad idea.

[niorn]

Hi,

You should try a product called Debond or 3M Silicone softener. Debond works the best.

[feetup]

Thanks niorn
I suspected there would be a product to soften silicon, do you know if it is safe on fiberglass os lexan?
The reason I am looking for an alternative to a razor blade is that the interface between plexiglass and fiberglass forms a right angle that would be very difficult to cut into.

Feetup

[redcorvette1995]

Hi!

Debond will attack lexan.
I don't have any experience with the silicon softener.
I would try and test it first.

Todd

[hellosailor]

Feetup, I would expect most of the solvents could hurt (eventual cracking and crazing) your deadlights, whether they are polycarbonate or (more likely) plain acrylic. If you can drill or pick or chew one small hole all the way past the edge, you can pass a piano wire or mono fishing line ("Spidersilk" or other aramid/kevlar material) through the hole, and working with two people, saw it back and forth around the deadlight to cut the sealant.

Depending on what it was bonded with and how well it was bonded, simply pulling or pressing just may not do anything. Using a heat gun and really heating it up as much as you dare, might help release it.

But you may just need to replace the deadlights, or find that's the easiest thign to do. If they are just 1/2" sheet plastic, any plastics shop should be able to made replacements for you at a reasonable cost.

[sailingdog]

The product manufacturer should be able to tell you if it will attack different materials.

[Doug_53]

Try WD 40 and a plastic scraper

[hellosailor]

WD40 is effectively kerosene, it will harm both lexan and plexi unless immediately and thoroughly washed off. Makers of both say simply "never" to get petrochemicals on them. (Long term crazing downline.)