Fixed Window Silicone Sealant Removal

[Joyride]

Hi Gang,

I decided to replace the crazed and ugly fixed windows on my 91.  I as soon as I started the project I regretted it...as they weren't leaking or weak at all.  I got the windows out finally and duplicates made by a reputable shop in Sarasota.  Now I need to get the black sealant off and its a major pain.  I've used razors, scrapers, sand paper, and finally a wire wheel to make it go fast.  Anybody have a particularly good method for doing this?  The wire wheel is making quick work but I'm also sure that I'll make some marks if it gets away. 

[paule]

Try rubbing alcohol, goof off

[Noah]

https://c34.org/bbs/index.php/topic,10228.msg78760.html#msg78760
A sharp scraper and perhaps some Debond spray. But scraper worked for me.

[Jon W]

I sprayed Marine Formula by Debond Corp, and let sit for a few minutes. Then used a putty knife and green 3M pads. Worked great.

[mdidomenico]

i've found some of the stiff plastic putty knives at lowes to be pretty effective.  you can generally sharpen them with sandpaper into a seriously sharp razor edge.  the plastic knife will general slide through the caulk.  if you do it at a shallow enough angle you can generally just rub away what's left with some acetone/mineral spirits.  the nice thing about the plastic knives it they generally aren't stiff enough to marr the gelcoat

[Jim Hardesty]

I like plastic razor blades.  Sometimes can find at home improvement stores.

https://www.amazon.com/plastic-razor-knife/s?k=plastic+razor+knife

I feel your pain, many jobs the prep is most of the work.
Jim

[Joyride]

Ok I got all the stuff off.  This did not go that well for me and I tried about every sharp tool and solvent I had and still ended up sanding a long time. 

Next question...anybody ever rebed these with butyl tape instead of the sealant (I have the recommended Dow 795)?   I had the screw holes drilled so that should give some bite to compress the butyl. 

[KWKloeber]

Use the recommended method, the adhesion tape, 795, no screws or remove them after install. Butyl is not for this application.

Edit - (The factory instructions are on the wiki site.)

[Rortega46]

Last spring, the most respected boat windshield guy around was too busy to change mine so he gave me a lesson and instructions. He has been doing boat windshields over 40 years and he uses butyl tape.  Below are his instructions which worked great for me.

- Remove existing windows and all related caulk and residue.  From the exterior, pull/push razor knife blade away from you repeatedly as you extend the blade to cut deeper and deeper until a 2nd person on the interior is able push a corner of the fixed port away from the frame.  Thereafter, cut the remainder of the caulk to remove the port as the person on the interior pushes out.  Remove all remaining caulk residue with razor knife blade and finally wipe clean with ?.
- Tape inside of window frame
- Tape outside frame and of window to nearly up to (1/16") old gasket area
- Tape exterior edge of window leaving an even gap in around
- Apply continuous loop of butyl tape around window frame opening leaving approximately 3/8 inch inner edge for adhesive (Do not remove outside paper from butyl tape yet)
- Add second layer of butyl tape only if additional offset needed
- Temporarily tape window in place and visually look inside to check alignment
- Add registration marks from tape to window paper top, bottom and sides
- Remove tape from butyl and apply caulk (Boaters life Life seal 50/50 (silicone & polyurethane) black caulk) to window frame above and below buytyl). Keep caulk 3/16" from butyl And bead should be 3/8" wide and 3/8" high. For bigger areas add caulk bead(s) so gaps will fill when compressed
- Insert window and Align registration marks
- Add 2-3 tape pieces (hangers) to hold alignment
- Push window in place (left right top and bottom)
- If outside edge not filled add caulk 6 inches at a time with caulk gun hook nozzle (smooth with soapy water and mineral spirits spray).  If caulk is not drying rapidly OK to do entire exterior bead. Leave slope so water does not accumulate
- Use small plastic squeegee to clean up caulk inside then out rapidly
- Remove interior tape and window paper
- Remove exterior tape then window paper
- You are done

[KWKloeber]

Randy

Did you use the screws to old them in place until the caulk cured? Butyl alone wouldn't seem to have enough grab to keep them tightly in place or from sliding downward?  It seems that the 3M tape is the most typical way of holding them until the 795 cures.

[Rortega46]

Ken
No I did not use screws. The butyl tape held the window after being pushed in place.  BTW, I purchased replacement fixed windows from Catalina Yachts in Florida who did a good job.

[mdidomenico]

Butyl alone wouldn't seem to have enough grab to keep them tightly in place or from sliding downward?

given the gentle curve of the window i'm liable to agree with you on this, however, the most recent batch of buytl i got from Mainesail (2yrs ago) is seriously sticky.  i have a hard time peeling it off the deck and my fingers.