Advice for removing old window sealant

[marto26]

The long overdue maintenance of our Cobra 750 continues.

I removed the side windows on Saturday ready for replacement. Or rather, I removed the screws and the windows fell out. No wonder they leaked as badly as they did!

Any suggestions how to remove the hard black residual that’s left behind?

Looking back through some old posts in the forums here, and based on the information in there I plan to seal the new windows with butyl tape but how thick should I go?

Lastly, I'm sure I read an article somewhere that suggested adding a small washer at each screw hole to prevent over compression of the sealer. Any thoughts on whether that's worth doing or not?

Thanks in advance!

 

[jpd85]

Came across this article recently. thinking about doing it at the end of the season so would love to hear how you get on

Resealing boat windows - DIY project on a Sadler 32 - Practical Boat Owner

 

[LadyInBed]

Any suggestions how to remove the hard black residual that’s left behind?

If it's butyl, then two stroke mix should soften it. A wide wood chisel will help with the stubborn bits.

 

[kacecar]

Hadlow Marine, a specialist marine window supplier in Kent that supplied me with a kit for relacing the acrylic in an old Lewmar hatch, recommend stuff called "Detak Chewing Gum Remover", by a company called Clover I believe. They also recommend a scraper made from a bit of acrylic plastic. The Detak worked well for me, as did the acrylic scraper (sharp enough to remove the stubborn bits of old sealant, generally soft enough not to scratch whatever the sealant was stuck to and easy to sharpen as necessary).

NB: Usual caveat. I have no association with Hadlow Marine other than as a satisfied customer.

 

[Plum]

The long overdue maintenance of our Cobra 750 continues.

I removed the side windows on Saturday ready for replacement. Or rather, I removed the screws and the windows fell out. No wonder they leaked as badly as they did!

Any suggestions how to remove the hard black residual that’s left behind?

Looking back through some old posts in the forums here, and based on the information in there I plan to seal the new windows with butyl tape but how thick should I go?

Lastly, I'm sure I read an article somewhere that suggested adding a small washer at each screw hole to prevent over compression of the sealer. Any thoughts on whether that's worth doing or not?

Thanks in advance!

Agree with others that the best tool for removing old sealant is a scraper made from 8 or 10mm thich acrylic. I used the old panel from a forehatch. Sharpen one end like a wood chisel, but with a 45 degree bevel, to a very sharp edge and keep it sharp with a fine file. The width can be made to fit the need. Round off the other end to make it comfortable to hold. Does minimal damage to the frames/coachroof.

Www.solocoastalsailing.co.uk

 

[LoneHort]

been there done that , get a scraper as others said, also get a few can of this , Multisolve - CT1 great stuff

 

[waynes world]

Having done many windows over the years i have worked a few ways and this is easy and best for me. Once i removed the windows and stripped them back to the frame its out with the wire wheels in a fast drill to remove all left over adhesive/sealants from the frames. For the apertures i use a scraper then a sander with 120g , in my case a Multi sander to clean all the gunk back for new Butyl to stick to. Once all surfaces have been cleaned with acetone.

For butyl gun grade yes, use a small SS washer. But to make life easier use Butyl tape. It doesnt need a washer, less messy and you tighten down untill you see it come to the frame edge as you stick it to the frame first.
Use 3mm thick tape and a few mm narrow than the frame if you can, if bigger dont worry jus tighten down until it bites then a full turn and it will seal. then trim back the butyl from the frame. If you cant trim back if out of time, no worry do it another day. easy way is with a blade and run it around the frame edge and then peel off the extra butyl.

 

[Neeves]

Agree with others that the best tool for removing old sealant is a scraper made from 8 or 10mm thich acrylic. I used the old panel from a forehatch. Sharpen one end like a wood chisel, but with a 45 degree bevel, to a very sharp edge and keep it sharp with a fine file. The width can be made to fit the need. Round off the other end to make it comfortable to hold. Does minimal damage to the frames/coachroof.

Www.solocoastalsailing.co.uk

To add to this excellent advice - if you are replacing multiple windows then make up lots of these scrapers, all as sharp as possible. They dull easily and you are there to clean up the frames not sharpen acrylic. You can usually find scrap pieces of acrylic in the scrap bin of the supplier to you of the new windows. Put time into making the 'handles' comfortable to use. Acrylic will not damage the gel coat.

Jonathan