Well I got the hydraulic leak solved but now the sunroof (which I believe is polycarbonate) has come loose again. I recently re-installed it with Dow U-428 glass adhesive but the bond between the adhesive and the polycarbonate came loose after using it for a couple of hours. Does anyone know what the proper sealant is for this application?
My two cents, call your local CAT dealer, they may sell some factory OEM sealant for that, worth a call
Here's the procedure for installing a polycarbonate roof window on an excavator. You might be able to use the same adhesives & procedure for your SSL.
Is the plastic panel a genuine part or a locally cut piece? The original one has a machined, roughened band around the perimeter for the adhesive to bond to. I use Sikaflex and don't have any problems.
It's most likely polycarbonate and, as such, Sikaflex is the adhesive of choice. I purchase it through Jamestown distributors as they turn the stock quickly (it has a shelf life).
Yes, the plastic roof panel (which I understand is polycarbonate) is a genuine Cat part with the roughened band around the perimeter. Looks like Sikaflex has multiple sealants - is there a particular one that you've found to work best for this application? I called the local dealer and the lady was most helpful; unfortunately she thought I was having issues with the back window, not the sunroof. Thanks for all the help!
If you re installed it, the problem was more likely the surface preparation than the adhesive used. I'd clean the plastic with a wire brush, and solvent if you trust it. They make primers for polyurethane sealants for applying to existing sealant or plastic, which are harder to adhere to than glass or masonry. The dow product is designed for glass and says not to use on hard plastic. You'll probably be fine without the primer if you get the failed sealant off the window, it will probably stick to the existing sealant fine. Is your skylight solid plastic, or glass like Nige's procedure, and did it fail at the skylight or at the old sealant?
The skylight is a solid sheet of plastic. I cleaned it all the way down to the bare plastic on the skylight and painted metal on the roof (was clean as a whistle). I did not use any primers on either surface. The plastic skylight pulled away from the fresh sealant I had installed a couple weeks earlier. At this point I'm thinking I should clean it all off again and use the right Sikaflex product (not sure which one).
Just for clarification the procedure I posted up was specifically for a polycarbonate roof window, so IMO exactly the same primers/adhesives and the same procedure ought to work on this machine.
The procedure referred to "bonded polycarbonate glass" so I didn't know what material was involved, regardless, the primers are mentioned in that procedure. The dow glass adhesive specifically says not for hard plastic. Any Sika, Vulkem, Dymonic etc. polyurethane available locally will work, they also make primers that will improve the bond to the plastic, the primer will be many times the price of the polyurethane and less easily available. I would not use PL, DAP etc. the other brands mentioned are available at the big box stores.
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