Cabin windows

[Mark Maulden]

Well, there have been numerous posts about S2 window replacements. I had the local yard do mine about five yrs ago cuz me and sealants just do not get along. They were bedded in with Sikaflex 295. A yr later they fell out. Yard owner said it looked like the special primer was not used and they were rebed. Fast forward to this year and was washing the boat when screams erupted from below. Water was pouring in from a window. The Sikaflex was falling out in chunks from the outer ring and is starting to happen with the others. Since there was water ingress, that also says the flat surface coverage and adhesion is also not good. There is nobody at the yard that was there 5 yrs ago except the owner and he is sailing in AK....Obviously, this has to be redone again and before fall..There are other yards, but it seems the worker workforce seems to make the rounds between them...They will not be redone with Sikaflex. Dow 795. Dont let anybody talk you into Sikaflex if you're contemplating window replacement...I may end up taking the boat to Seattle or Bellingham after an engine replacement....or Sydney BC... Gonna be a busy fall.

 

[BobM]

I was toying with the idea of black butyl tape to set the windows in and seal them then something else for the cosmetic aspect on the surface.

 

[Mark Maulden]

Thats a lot of tape as it would have to cover the whole adhesion area or it wont look good...

 

[BobM]

Butyl tape is pretty inexpensive.

 

[jtpollock]

In the S2 History and Referral Information letter from 1998 it is recommended to only use silicone for the windows. Quote,"Don't let someone talk you into using something other than silicone. The thermal expansion and contraction rates are drastically different between the plexiglass and the fiberglass. So elasticity of the cured sealant is critical." I too tried a "modern" 3M product only to have the windows let go in one season. I should have known better since the original 30+ year old silicone held on so tightly the plastic windows split from shrinkage.

 

[BobM]

Good to know.

 

[Bob McKee]

I made 3 posts on S2 window replacement, Aug 3, 2014, July 20, 2014 and April 9, 2009. All these are under my name Bob McKee. I made about 80 posts about the S2 9.2A I owned. I didn't use the factory method of installing the window,. I believe sealant is to seal, if you want something to stay, use bolts to hold and seal to seal. For sealant I used window glazer's tape, this is 1/8 X 1" black neoprene with adhesive on both sides. I used 3/8" plexiglas and it is standing up well.

 

[Mark Maulden]

So, did you use bolts?

 

[thinwater]

Well, there have been numerous posts about S2 window replacements. I had the local yard do mine about five yrs ago cuz me and sealants just do not get along. They were bedded in with Sikaflex 295. A yr later they fell out. Yard owner said it looked like the special primer was not used and they were rebed....

I've been doing some testing for Practical Sailor (related to sail repair) that basically determined that although polyurethanes can withstand UV, the bond area is VERY vulnerable to UV. Samples of sailcloth bonded with Sika and other PUs simple pealed after the reverse side was in the sun for a year. If the reverse surface was opaque, no failures. The Sika primer is intended to block the UV from coming through the glazing, but I'm guessing something was done wrong. This is a periodic failing with Sika 295.

Just use DOW 795. No problems. You should not need bolts--this is an architectural glazing product and is what most of the hatch manufacturers use.

https://www.practical-sailor.com/issues/29_13/riprap/4836-1.html

Subscribe and you would have known this!

 

[Mark Maulden]

Well, how come you didn't tell me this 5 yrs ago! Ha! Just got through bedding in six new windows with 795. I think the times when Sika was used, they just taped up the windows to cabin side. This last time, (different yard) we put some plywood just inside the lifelines and used it as a platform to apply pressure to the windows with a length of wood and wedges until it kicked. Not to much pressure so as to let the window float...I think it worked out great. The shipwright who helped out stated he has has failures with Sika.