The salon windows have been curing for over 7 days, so it was time to remove the clamps and blocks that were holding them in position and apply the remainder of the sealant to finish this project.
After breakfast I once again masked off the area around the windows in an attempt to try and keep the black goo from getting all over the gel coat. Between all the masking and the paper towels, I'm starting to wonder if there isn't a joke about how many trees you have to kill to install a plastic window.
After masking everything, it was time to see if the window holds without the clamps. I slowly removed the screws and fender washers, watching the nearby edge of the window for movement. The windows didn't budge as the screws were removed, so I now have proof that they not only don't leak (courtesy of the rain a few days ago), but seem to be adhered in place. Yay!
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| Some of the project supplies and tools |
I noticed there were a few places where I could not see sealant squeezing out of the back edge of the glass where the screws and blocks were, so I started by cutting the nozzle on the first tube of sealant rather small and trying to inject it into the voids. I then used my bent putty knife to push it around and pack it in behind the glass. Trying to work sticky goo into a 3/8 inch gap and around a corner is...lets just say it tries your patience. I then used the smaller nozzle tubes to fill in the back of the remaining gap between the window and the opening.
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| The better part of the tooled sealant bead |
Finally, I cut the tip to a larger bead and filled in the remaining gap. Someone who does this for a living could probably make it look nice right out of the caulk gun...but I am not that person. I ended up using my scrap from the flexible cutting board that I used on the anchor locker repair to "tool" the sealant edge. This produced a reasonably nice looking joint.
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| Windows all installed. |
But only to a point. The sealant started curing a bit and by the time I got all the way around the window, the joint didn't look as good. The stuff takes up to 21 days to fully cure, but apparently will start getting tacky in under 15 minutes. Oh well. I'll have to live with Bill's 20-foot rule....if it looks good at 20 feet away, it is good enough. Removing the masking and the film that protected the glass was equally challenging as it was starting to skin over. If you ever try this, try to have an assistant or two available so you can do these steps fairly quickly.
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| I can see outside again. |
In the end, I only needed 13 tubes of sealant for both windows. I guess those that needed more didn't do the second ring of foam 5/8" from the edge of the glass and probably also used the 1/2" foam so the window was flush with the opening instead of recessed like the original installation.
So, all the sealant is applied and one more big project is ticked off the list. Good thing since I want to be headed south in a week.
I'm about to attempt a similar project on my boat and found your write up helpful. Erick at Quest For Wind and Waves also did this and extensively documented it in his blog. He used Sikaflex primer rather than thinning the 795, but basically did the same thing you did.
ReplyDeleteI'm wondering if or how you masked off the interior from squeeze out. I'm replacing old ports, and will have to epoxy the unfinished edge around the hole and want to keep it looking nice from inside as well as out.
Glad you found the posts helpful. I *think* R&C originally used Sikaflex products for the install and the specific failure requiring the windows to be rebed ended up being the blackout paint failed to adhere to the acrylic...so I didn't want to risk that happening again. Thinning the 795 was a trick I found on the LeopardCat owners group on Yahoo and it seemed to be meeting with success.
DeleteIn my case, there was no need to mask the interior. The windows are installed over a 3/8" foam weatherstripping to hold the glass away from the hull and provide a gap for the sealant. You can see the foam in first picture in this post. The foam acted like a dam for the sealant, and since there were two rows of the foam between the sealant channel and the interior, any small amount that managed to make it over the first would be blocked by the second. There was no squeeze out on the inside. Hope that makes sense.
This all worked well for the large mounting surface in my Leopard, not sure how it will apply to other boats though.