De-Bond 5200 and Silicone!

[botanybay]

Originally Posted by hellosailor

In the interest of DRY BERTHS and other good things...

I'd first peel/scrape off the silicone sealant. Often it just peels from lexan and plexi. Then, because the silicone often leaves residual oils, use an appropriate solvent cleaner, i.e. 3m "Prepsolve" used to remove silicons and waxes before paint jobs. The solvent needs to be something that won't attack the plastic but will attack residuals.

After the solvent, follow the instructions for the adhesive. Sanding alone sometimes just embeds residual solvent--so you prep clean before any sanding. Then prep clean again to get rid of any sanding dust. The adhesive may require that a special primer be used, and they're usually not cheap but if you skip them, the adhesive may not work properly.

Once you find out what the proper adhesives are, whether it is what GE (makers of Lexan) suggest, or what Goiot suggest, whoever, the rest will be detailed in the instructions for that product. Anything from the top names should do the job and do it well, if they are followed, and if the hatches were originally built properly.

As to why they leaked in the first place...We'll blame that on the usual suspects. You didn't hold a proper wedding, didn't place a gold coin under the mast step, didn't make adequate libations, so Poseidon is reminding you.

:-)

On the large portlights on my Cruising CAL 35 I used 1/2" Lexan ports with aluminum which covered the deck by 1" and covered the Lexan by 1" with the holes through the aluminum only going through the deck, no holes in the Lexan.

At any rate, I used two sealants over the years, both recommended by GE plastics division: Silpruf and Lexsil, both worked well in this application but I was always using new Lexan when reinstalling so cleanup of the Lexan was not an issue.