Removing two part polysulphide

Capn_Tom · Post by **Capn_Tom** » Sat Jun 02, 2007 1:38 pm

After removing my teak decks I am left with a coating of what I assume is two part polysulphide. I am planing down the deck boards and reinstalling with epoxy rather than screws. I need to remove the old adhesive in order to ensure a good bond from the epoxy. It would seem that if I grind off the sealant I will contaminate the remainig gelcoat. Any thoughts on a chemical remover?

Hirilondë · Post by **Hirilondë** » Sat Jun 02, 2007 1:59 pm

If it is in-fact a polysulphide then I know of no chemical remover. I use a semi-sharp chisel layed almost flat on the surface to scrape the stuff off. Lifecaulk, a one part polysulphide is supposed to be sandable, though I have never tried sanding large areas of it. If you are going to glue the teak down with epoxy then I wouldn't worry too much about removing a little gel coat as you will be waterproofing during the gluing phase. Unless someone knows of some miracle stripper I think you will have to try a few physical techniques (sand, scrape etc.) and develop a process you feel comfortable with.

Capn_Tom · Post by **Capn_Tom** » Sat Jun 02, 2007 3:41 pm

Should I be concerned about sanding the polysulphide into the glass? Will this cause adhesion problems?

Post by **Tim** » Sun Jun 03, 2007 7:05 am

Scraping the bulk of it is your best bet. I have sanded one-part polysulfide with good results, so that might take care of the remaining residue. I don't know about 2-part, but it ought to react similarly. As a flexible substance, grinding it isn't necessarily fun, but it is possible. Use coarse open-coat sandpaper, and modify your technique as required to prevent the pads from overheating and turning the polysulfide into glue. I think you'll need a lot of sandpaper.

If you grind, I suggest an heavy-grit grinding to remove the bulk of hte material, and then going over the areas again with new sandpaper to clean up, changing discs frequently to prevent overt contamination. A good acetone bath ought to take care of the final cleanup and prepare the surface for the epoxy. Grind more, not less, and I don't think you'll have a contamination problem. I've ground off plenty of regular polysulfide residue with no ill effects.

While you want to avoid obvious contamination, the good news is that polysulfide will not contaminate in the same way as the evil product silicone. I think you should have good sueccess.

Ric in Richmond · Post by **Ric in Richmond** » Sun Jun 03, 2007 9:05 am

Here is one of those jobs a fein tool and a stiff scraper blade is your best friends.

Try it you will like it!!!

Ric

Capn_Tom · Post by **Capn_Tom** » Sun Jun 03, 2007 9:42 am

The residue is not vey thick and the deck surface is molded non-skid so I dont think the multimaster would have much value in this application. Since the consensus is that contamination isn't a real threat, I'll grind the non-skid off with my pc sander. Given the need for frequent disc changes this may be an instance when the "Only Sanding Discs for your Project" are not the best choice. I'll know as soon as the weather clears! As an aside the deck boards were firmly stuck to each other by the seam caulk but the entire section lifted from the deck without any effort. Anyone with older teak decks might want to check theirs. On the plus side I haven't found any spongy areas but it is difficult to sound the side decks since the polysulphide softens the blow. After sanding I will sound the decks and take samples if necesary.