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Tips on How to Repair Leaking Aluminium Boat windows

Posted by Robbie 
Tips on How to Repair Leaking Aluminium Boat windows
19 December, 2017 16:10
I recently posted a Question and was looking for advice on fixing leaking Motor Boat windows,
I did extensive Internet research, and approached the task with the knowledge gained

I have put together the process I used on one of my more Awkward windows, YES I have more,
Later when I am putting the windows back in Place on the Boat, I will Post this process also. As this is a different process

IMPORTANT Before you start this process you have to understand that pasting Sealant on the outside of the glass or frame is not a solution, this is only temporary and cause more Problems

Repairing my Leaky boat windows

Tips before you start
1. Have a clean uncluttered work area
2. Essential have some one to help, this is not a task that is easily done on your own
3. Mark all the parts before you dissamble
4. Make sure you Put alignment marks so the glass will go back to the exact same Position, in the frame ( I failed to do this on the 1st window and had to take it apart) and this was a very messy task
5. If you can do a dry run
6. Cut 2 blocks of wood with some channels to hold the glass and frame upright, this will make assembly easier
7. Have all tools & Clean rags and Thinner ready NOW, as when you apply Marine Sealant, it has a relatively short setting time
8. You want the Rubber seals to run continuously around the frame, ie only one joint

My Proceedure

1. Remove and clean all parts really well with scraping and wiping with thinners
2. I started by working from the Bottom up, so any rubber Seal butt joints would be at the top of the frame
3. I ran a bead of Marine Silicone into the Rubber U Channel, and then fitted to the cleaned Glass
4. At the corners I cut off the bulging excess Rubber and formed a tight miter type joint, with extra Sealant here to compensate.
5. I ran my hand firmly around the Rubber to squeeze out sealant to the sides of the glass
6. Now apply a small bead of Sealant to each side of the Aluminium channel just at the top edge, this will act as a lubricant to the glass/rubber and when dry a sealant
7. Working from the bottom of the fame upwards I aligned the Glass to the register marks I placed earlier, and tapped lightly with my Rubber mallet to slid the glass into the recess
8. We assembled the 2 sides, and secured the bottom corners with the screws, tapping gently and nursing the rubber into place
9. Lastly we put the longer top piece on and secured the corner screws
10. we placed a set of clamps across the frame as one of the Alu tracks was offering resistance to staying in place, and from the picture you will see how we stopped the clamp from slipping
11. We cleaned up as much of the excess sealant off the glass and track, but this was minimal.
12. when the whole unit was dry the next day we cut back any excess rubber and pared back any Sealant that oozed out.
12A. Job done and we are very happy with result
14. This is a task that I would definitely get better at as I go forward, especially the amount of Sealant that needs to be placed in the Rubber U channel and on the Alu frame.

I know you are probably thinking why do you need Sealant with a Rubber U seal, well 2 reasons that I can suggest are

1. The Sealant actually helps you squeeze in the glass to the Frame, as it acts as a Lubricant
2. The Sealant when set, Holds fast all parts and makes a complete weather tight seal, that will last for many years, Marine sealant is UV Safe and forms a permanent Weather seal between the rubber & Glass and the Rubber and the Aluminium Frame, it is also very Flexible. The sealant we used was Rubber, Glass and Aluminium Friendly

View Images at Link below ........ Scroll down and click on ....... "View Album" []

I hope this is of help to some other boaters, & if you have any questions, you can either PM me or leave a comment.

Edited 1 time(s). Last edit at 19/12/2017 16:26 by Robbie.
Re: Tips on How to Repair Leaking Aluminium Boat windows
19 December, 2017 19:44
Very interesting. Thank you for posting!

I think this job is ahead of me at some point. I assume that, when you put the windows back in, you will use some sealant between the frames and the window openings? Also, where did you find replacement marine grade rubber U seal?
Re: Tips on How to Repair Leaking Aluminium Boat windows
21 December, 2017 14:06
Hi Doug
Thanks for commenting.
I got the seals from [] there are Irish suppliers but to be honest I found they didnt respond in time or were not interested or helpful...!!!!!!
Make sure you get a seal that is not too tight....... they will send you samples, Reason for this is that if the seal is tight it will push all the Sealant away and you wont get a great seal, too loose will be opposite.
My gauge here is you should be able to push in the glass with the seal into the frame without resorting to bashing it with and force.
Also make sure you use a good Marine grade sealant
I will be rebedding in the Frames soon, this is a different process and I aim to use Semi setting Butyl sealant.
I will post on this later .. Hope this helps.. you can PM me if you want to chat
Re: Tips on How to Repair Leaking Aluminium Boat windows
18 October, 2018 14:31
Good information there thanks.

I'm doing the same thing at the moment, I'm going to have major problems taking the windows apart though. They are made from extruded aluminum (profile is a lower case "h"), each frame is made from two single pieces with the top half and bottom half of the window being joined with 4 countersunk flat head screws on either side, these won't budge. I drilled out 4 of them last night.

Were the rubber seals expensive?

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