I need a solution to a developing problem

I glued the 1/2" thick tempered glass windows in my pilothouse w/3m5200 (black). They are glued into a routed wood grove 1/2" x 1/2"; glued to both reveals. After only 1 year the 5200 is releasing from the glass on the back side. I checked on the expansion/contraction rate of both the wood frames and the tempered glass before I assembled the two. The rate is nearly identical so why the separation? I have been told that anything glued with 3M's 5200 will never come apart. Do any of you experienced boat builders have a clue whats up or how to remedy this issue?

Have a Spiffy G'Day
Earl

 

See this thread.:
http://www.boatdesign.net/forums/wo...on/bedding-new-windshield-what-use-33162.html

 

Yes, the stuff has (reportedly) not the flexibility to stand that. Sikaflex would have been the right solution!

http://www.boatdesign.net/forums/wo.../bedding-new-windshield-what-use-33162-2.html

Regards
Richard

 

ecflyer, this is not my chosen field but we work on a lot of fast sport fish boats with way too much "window glass" area and it has been interesting to note the way the factory reps have attempted to improve the situation. You may have noticed that 5200 has changed in recent years. The new formulations won't work on glass as well as some of the Sikaflex products currently available. Some of the "pros" from the factories have been using Aerolite with a primer supplied. Some like Sikalex (sorry, don't know the part #). But it seems like the most important part of the process is to sand the bond line on the glass. Pretty obvious because glass is so damn slick, but it's surprising how many techs don't do it.

 

That sounds logical but is untrue.

Sika primer, as mentioned above, does stick to a non etched, non sanded glass strucure.

Sanding glass in a wheelhouse or saloon application on a ocean going vessel is a mad idea!!!!

It weakens the glass structure to a inacceptable extend.
Every scratch in a glass structure is a weak point, sanding makes lots of scratches..........

Leave that!

Regards
Richard

 

Nonsense.

 

sika seems the logical way, we always use it BUT the correct primer is essential
i recently had a windscreen replacement on a car in UK, the man used sika a number, and primer I had not heard of, he said he and his three men did 18 a day
Cars are not boats, but they do blast through rain at 100mph
i would contact Autoglass uk OR Carglass Germany, because as sure as sure is sure I am going to use it next time
i found this but really I would go straight to them and ask My guy did not wait two hours
Sealing glass first requires use of Sika Activator, which is a specially designed cleaner for glass. Allow the cleaner to dry for two hours as well. Using Sikaflex-296, applying a thin coat at the gaps between the glass and the adjacent material to which you want to seal the glass. If there is excess Sikaflex-296, use Sika Cleaner 205 to remove the excess. Allow the sealant to dry overnight.

 

I must disagree. Having cut customized glass for customers, I always began by introducing a scratch along the surface along the line or arc of the cut. It was "prescribed".

 

I am contemplating taking a crash course in brain surgery.

Please volunteer for a lobotomy, you'll do us all a big favor.

 

5200 has no UV filters. Sika makes a product specifically for that. I think 3M has something now too.

 

Wouldn't the wood frame expand and contract as it absorbed water and then dried out? Maybe that problem should be taken care of before sealing the glass to it.