Catalina 34

General Activities => Main Message Board => Topic started by: vincents34 on August 08, 2011, 03:04:40 PM

Title: Fixing leaking fixed portlights
Post by: vincents34 on August 08, 2011, 03:04:40 PM
I have looked at all the different products, discussions and it seams to be a ongoing issue?
Has anyone found a sure way to fix the four fixed windows that will actually work?
Is the pattern of the windows the same for every Cat 34? If I order the 4 from Catalina
for $400.00 will they be the right size?
I am sure all the members would love a final solid answer ?
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Ken Juul on August 09, 2011, 04:35:04 AM
Are your windows cracked or just leaking?  If just leaking no need to replace. remove them and thoroughly clean both surfaces.  Apply silicone sealant and reset the windows, using the tighten until some compression of the sealant is seen then let sit overnight to cure.  Finishing tightening the next day.  Silicone is the only thing that will stick to the window.  

I curious though about using butyl tape.  Some call it Glazers tape because it is used to set commercial windows.  But they are glass, so the butyl might not stick to the plastic.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Tom Glennon on August 09, 2011, 01:23:16 PM
Catalina uses a Dow product: Building Sealant 945?? something like that... it is used to seal the large windows in commercial buildings. You don't need screws to hold the windows in with this stuff
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Ron Hill on August 09, 2011, 05:54:58 PM
Guys : Gerry Douglas has mentioned that the biggest problem that people have with re bedding the 4 fixed port lights, is that they do not use small pieces of tap to provide standoff between the lens and the window "frame". 
What happens is that with a double curvature, you squirt out the caulk when the lens is put in place and secured.  Then there is no sealant between the lens and the frame(cabin side).   A thought. 
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mtullier on August 09, 2011, 07:35:20 PM
I just replaced all four of mine and used Dow 795.  Worked great with no leaks and is easy to work with.  The key is to clean ALL the old adhesive off.  I sanded the inside of the window with 220 where the adhesive lays against the fiberglass to give the plexy better adhesion.  The DOW 795 can be purchased from catalinadirect.com.  Hope this helps.

Mike
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Clay Greene on August 10, 2011, 03:40:52 PM
I posted the Catalina directions for re-bedding the windows in the Tech Wiki when we re-did the window over our head last year.  The hardest part of the process was getting the old cracked window out.  Good luck on taking the window out without cracking the plastic in the process.  Using a wire to break the seal around it may work if you can create a hole to get the wire through.  I would plan, however, on cracking at least one of the windows in the process of removing them. 

The second hardest part of the process was getting the window frame clean.  That required a lot of work with solvent and a putty knife.  It may be leaking but it is not going to come out easily.  Actually reinstalling the window was the easiest part, although it was messy.  We did use the spacers and you can see them if you look closely enough at the window even though we used black tape.  I try not to look too closely. 

And to confirm what someone else already said, the screws are superfluous.  Catalina used them just for securing the windows while the sealant cured.  If you secure the window appropriately to keep it in place, forget about the screws. 

If I remember correctly, Catalina Parts suggested that we draw a template of the window so they cut it the right way.  It is a special order job for them - they don't have old Catalina 34/36 windows sitting in a box in the back of the warehouse.  We sent him the window pieces taped back together instead.  The replacement window fit perfectly. 

The Dow product specified by Catalina is not easy to find.  You most likely will have to go to a commercial building supplier.  We could not find it in local hardware stores.  The local building supplier actually just gave us a couple of tubes because they deal in quantities like grosses. 

Good luck!
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Clay Greene on August 10, 2011, 03:44:12 PM
Here is the link to the instructions we received from Catalina:

http://www.c34.org/wiki/index.php?title=Instructions_for_replacing_large_fixed_side_windows
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Roland Gendreau on October 21, 2014, 09:51:19 AM
I've read a number  of threads on fixing window leaks.  On my C34, the window over the ice box is leaking - and there is actually a small crack just above the window.  The window itself is crazed a bit, but there is no crack in the Plexiglas. When I look at the outside of the window, there does not seem to be any void in the sealant around the Plexiglas, nor is there any crack in the fiberglass.  So I don't know how the water is finding its way into the crack. 

Has anyone had a similar crack develop and how would one fix the crack?


Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Jeff Tancock on October 21, 2014, 03:27:41 PM
This is a job that I need to do. I developed a large crack (maybe 2") down from one of the screw holes. It leaked into the galley area. I didn't have time to deal with it at that time so I smeared a generous dab of silicone on the crack until I could get to it. That was 1 1/2 years ago. Still dry and still need to get to it!
I have been dreading the removal and cleaning part, but also not sure about how to secure the window easily without using screws in spite of reading the instructions. Maybe in the spring?
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mregan on October 21, 2014, 04:49:54 PM
I replaced my starboard side ones last year.  I used a utility knife on the inside seal to get the window out.  Once I was able to get one portion free, I would push the window out a bit to expose a bit more of the sealant and cut that with the knife.  The PO had used silicone on them so it wasn't too bad to get them out.
Then spent a while with the utility knife, paint scraper and acetone & goof off to try to get rid of all the old silicone.

My windows were really crazed so I brought them to a local plexiglass shop and the fabricated new ones.  The inside edge of the window is beveled.  The plexiglass shop couldn't router the correct angle so he did it as much as he could.  I then took a grinder and ground down the edge all the way around.  Took a few tries.  I would grind, stick it into the frame, see where it didn't sit flush then grind some more.  Once it sat flush, I took some black 1/2" wide by 1/8" thick foam gasket.  One side was sticky so I cut up a bunch of pieces and placed them every 6-8" around the window frames.  This keeps the window off the frame and gives a gap for the sealant so it all doesn't get squirt out when you put the window in.

Then I took blue painters tape and taped off around the inside and outside of the window frame for any sealant that spilled out.  Then I filled the whole recessed area, that the window sits in, with black Dow 795.  I used almost a tube per window.  If you don't use enough you will get void and can see them through the window.  Use more than you think you will need.  Whatever squirts out will just go onto the painters tape around the frame.  Make sure you tape off a couple of inches thick on the outside.  The black sealant gets everywhere.

Also, leave the sticky paper on the plexiglass frame (if you get new windows)  If using the old window, I would tape off a good 2-3" around the edge of the window on the inside and outside.  On the inside, you need to leave about 3/4" of the window exposed around the edge.  This is where it will sit in the sealant.  Since I had new windows with the paper, I put the window in place, traced the outline of the window frame on the inside, then used a razor blade to trim that amount of paper off to accept the sealant.

Once I had the sealant on the frame, I put the window in place.  I found if I pushed on the window it would sit tight but then slowly start to lift off.  Not enough to fall out of the frame but enough that it was noticeable.  You would need to rig something up to keep pressure on it until the sealant sets.  I ended up putting a couple of screws around the window to hold it in place.  The screws are small and look fine.  Once it was set in place, I used my finger around the edge of the window to smooth off and push in any sealant that squirted out when the window went in.

After and hour or so, the sealant starts to set.  There is an outside skin that is dry but if it's a thick blob, the inside will still be mushy.  On the inside of the window, I took a razor blade and sliced off any sealant that had squirted between the window and frame.
Waited 24 hrs then pulled all the tape off.  Since I had taped everything really well, there was almost no cleanup needed.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Jeff Kaplan on October 21, 2014, 05:38:09 PM
Vincent,

Years ago I replaced the four ports on #219, got them made at a plastics company. As others have stated, it was quite a job getting the old ports out, but I got them out intact, and the plastics company used them as the templates, beveled correctly and holes drilled. I got smoked grey lexan.  Make sure you clean the structure very good.  I got a roll of butyl rubber, maybe 3/4" wide and formed it around each port.  Placed the new ports on and screwed  them in place, trimmed excess off.  As fate would have it, a rain storm came in a few days later.  I went to the boat to check for leaks and found a few. To fix, I just took a few small pieces of the butyl rubber and forced them into the leaking areas,from the inside. The butyl will stay flexable for years.  The ports have been in for years now, and I have never had another leak. A tiresome job but the end results are worth it. good luck.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Andrew Harvey on October 22, 2014, 08:16:42 AM
I agree with Jeff.
I took the old windows out and they were used as template for a plastics company to reproduce in Lexan.
Black Butyl tape has been in place for about 5 years with no leaks.
Only mistake I made was not choosing a darker tint. it looked the same in the shop but they are much lighter or transparent on the boat.
Andrew
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Jeff Tancock on October 22, 2014, 09:44:44 AM
Butyl tape sounds like an interesting option.
I have never used it......does it skin over or does it smear if you touch it?
Is it easier to work with compared to a tube of sealant?
Any cons using tape?
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mregan on October 22, 2014, 12:38:51 PM
Easy to work with.  Doesn't smear or skin over.  To make a good seal with it, you need to apply a good amount of pressure.  Best thing would be to use the screws to hold the window in which would put a good deal of pressure on the butyl and create a good seal.  The nice thing with he butyl is, once you get a good seal and it's sticking to the window, you could pull the screws out and it would stay in place just fine.  It's the initial adhesion that is important.  That being said, if you had the windows stuck on and needed to pull them off, you can re-use the butyl over again.  Doesn't need to be replaced everytime.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Ron Hill on October 22, 2014, 02:19:48 PM
Jeff : Mainsail does not recommend using butyl rubber tape bedding the fixed port windows.

A thought!
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Jeff Kaplan on October 23, 2014, 10:20:34 AM
Ron,

I got the butyl tape from a company that makes replacement ports for all boats.  As stated, I got the ports replaced by a local plastics company.  The ports have been in place for over 6 seasons and never a problem.  The rubber never dries out, remains flexable, completely seals out water and I would recommend this proceedure be done as the most effective way to re seal, replaced ports.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: KWKloeber on October 23, 2014, 05:20:48 PM
Quote from: Ron Hill on October 22, 2014, 02:19:48 PM
Jeff : Mainsail does not recommend using butyl rubber tape bedding the fixed port windows.

A thought!

Ron,

Wow that's something I haven;t heard - I know he had used it on other ports and wonder why the difference?
Do you have a pointer to the article or RC's post on that?

Ken
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Jeff Tancock on October 24, 2014, 07:54:03 AM
I believe that Mainsail wouldn't recommend Butyl for this application is because it is a good sealant but not an adhesive. If there isn't a mechanical attachment (screws or bolts) it won't work so well as it wouldn't be secured. That would suggest that it all depends on how well the screws hold the lens in place....
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: KWKloeber on October 24, 2014, 08:04:07 AM
Quote from: Jeff Tancock on October 24, 2014, 07:54:03 AM
I believe that Mainsail wouldn't recommend Butyl for this application is because it is a good sealant but not an adhesive. If there isn't a mechanical attachment (screws or bolts) it won't work so well as it wouldn't be secured. That would suggest that it all depends on how well the screws hold the lens in place....

WOW.  Duh. Apologies.  I had my C30 hat on (framed windows.)  Of course one wouldn't use butyl on the PGlass windows!

Ken
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: stevewitt1 on October 24, 2014, 05:06:35 PM
hey all:

Sometimes I think I ate dumb donuts for breakfast but I'm really having a hard time following the conversation here.  I hear references to screws, frames, the deck (not cabin trunk), the head and I'm still not clear on what is being replaced.  My 34 (1989) has two large plexiglass fixed windows on the "cabin trunk sides" and three opening ports overhead. (one in the main salon, one in the V-berth and one overhead in the head.  Then there are 6 (three on each side of the cabin trunk) opening ports as well as two opening ports in the aft cabin that open to the cockpit.

Apply 30# of lead weights eliminates the large plexiglass windows on the cabin trunk sides

Screws seem to eliminate inserts on overhead hatches but I have corner screws in my large plexi fixed cabin trunk side windows.

Or are we talking about the opening ones??

I haven't been able to visualize the spacers being talked about.

Someone please help steer this feeble mind in the right directions.
Thank You in advance


Steve

visit us at ......www.ocontoyachtclub.com (http://www.ocontoyachtclub.com) and www.warbirdsix.com (http://www.warbirdsix.com)
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mregan on October 24, 2014, 05:15:53 PM
We are talking about the 4 fixed windows.

Originally, at least on the MK 1, there were screws in the fixed windows along with sealant to hold them in place.  I think, and I don't know because I don't have one, the newer 34's had the fixed windows without screws.  When some people replaced their fixed windows on the MK1, they didn't use screws.  Others did.  They aren't really needed but I found when I replaced my windows, the screws held the window compressed against the cabin so the sealant could get a good hold.

As far as the spacers.  If you were replacing the windows and just applied sealant to the cabin frame, then pressed the windows onto the sealant, if you pressed too hard, there is a chance all the sealant would squirt out and you wouldn't get a good seal.  With adding a thin foam spacer, say 1/8" thick, no matter how hard you press the window against the cabin, you will always have a 1/8" gap which will be filled with sealant so you don't have to worry about the sealant squirting out.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: KWKloeber on October 24, 2014, 05:20:26 PM
Quote from: stevewitt1 on October 24, 2014, 05:06:35 PM
hey all:


Apply 30# of lead weights eliminates the large plexiglass windows on the cabin trunk sides


Steve

visit us at ......www.ocontoyachtclub.com (http://www.ocontoyachtclub.com) and www.warbirdsix.com (http://www.warbirdsix.com)

Steve,

Here's the object of the topic:
http://www.c34.org/wiki/index.php?title=Instructions_for_replacing_large_fixed_side_windows'

I missed any mention of 30# of lead?  I must have a carrot deficiency.  Too many doughnuts?

Ken
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mregan on October 25, 2014, 02:58:32 AM
I used screws when I did mine.  Didn't need the weights.
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: Noah on October 25, 2014, 08:30:24 AM
Nice research/directions post Ken! When I do mine (they are crazed but can wait awhile down the road) I am considering foregoing the screws and usong the "Fred K" jig technique.
http://c34.org/bbs/index.php/topic,7688.msg52834.html#msg52834

Seems like it will apply the best even pressure. Just wondering how many black foam tape spacers to use and where to buy them?
Title: Re: Looking for best way to fix leaking windows on 34 Cat
Post by: mregan on October 26, 2014, 02:27:44 AM
I spaced the foam spacers about 6-8" apart.  You can get a role at any hardware store.  I used 1/8 thick.  Make sure you get black.  If you use grey or white, you will see them through the plexiglass.
Title: Re: Fixing leaking fixed portlights
Post by: Fred Koehlmann on October 27, 2014, 07:24:55 PM
Noah, here is a link to the complete operation of me replacing the windows in an older C&C 30 [http://blog.koehlmann.ca/marine-maintenance/replacing-the-main-port-windows/ (http://blog.koehlmann.ca/marine-maintenance/replacing-the-main-port-windows/)]. It should be reasonably self explanatory. Let me know if you have any questions. Foam or rubber spacers from a home build centre will work. If using foam, it should NOT compress easily. Also to make life easier, you may want to tack or glue them in place, so they don't move when laying up your window over the silicone. On the Catalina you have a slight advantage because the window sits inside a slight well or depression, but you may still have to help centre it within that space.
Title: Re: Fixing leaking fixed portlights
Post by: Noah on October 27, 2014, 09:30:27 PM
Thx Fred. I appreciate it!
Title: Re: Fixing leaking fixed portlights
Post by: KWKloeber on October 28, 2014, 12:45:54 AM
Quote from: Fred Koehlmann on October 27, 2014, 07:24:55 PM
Noah, here is a link to the complete operation of me replacing the windows in an older C&C 30 [http://blog.koehlmann.ca/marine-maintenance/replacing-the-main-port-windows/ (http://blog.koehlmann.ca/marine-maintenance/replacing-the-main-port-windows/)]. It should be reasonably self explanatory. Let me know if you have any questions. Foam or rubber spacers from a home build centre will work. If using foam, it should NOT compress easily. Also to make life easier, you may want to tack or glue them in place, so they don't move when laying up your window over the silicone. On the Catalina you have a slight advantage because the window sits inside a slight well or depression, but you may still have to help centre it within that space.

Fred,

Thanks for the great write up and pix of the window replacements -- this is especially germane to us C30 MK-I folks without the recessed windows, and with the "RV" aluminum frames.  Ours are NOT thru bolted or screwed to the coachroof, the screws between the inner and outer frames are totally within the cut opening.  As such, the holes in the coachroof are large, and at least on the C30 sometimes is difficult to center the frames in the holes because there may be only a half-inch overlap of the frame on to the fiberglass -- if pushed all the way in one direction, you see sky!

Using the trim piece is genius - usually it involved fiberglassing the gap between the outer and liner, and finishing off the openings to nice smooth, straight lines, and gel coating or painting them.  

I'm unsure whether the trim will easily work, at least on the c30.  The openings were cut so roughly and unevenly it's shameful.  The factory techs who cut in those windows definitely took "out of sight, out of mind" literally.  

I ran across an old, unretouched photo of an actual catalina tech eyeing up to make the precision window cutouts:

[attachimg=#]


I suppose we'd need grind out the openings to "oversize" so the lines are at least straight, and then apply the trim and (over)size the plexi accordingly?

Theres is actually a question in all this -- the foam or rubber blocks -- don't they detract from the adhesion?  I picture them eating up some of the space where 795 would have been sitting. I'd be afraid of a failure point -- not re: total adhesion of the plexi, but maybe just a "thin spot" and possibly a future leak point?  Also doesn't the trim piece outlining the hole, provide enough of a "block" to totally squeezing out of the 795?

Your thoughts?

Thanks,
Ken K
Title: Re: Fixing leaking fixed portlights
Post by: Fred Koehlmann on October 28, 2014, 04:07:24 AM
Hi Ken,

To be honest, I have not had to use the spacers (foam or rubber) since the trim piece provided me that spacing by default. These spacers however do not need to be large or continuous, and in some scenarios they can not. We have a glass shower stall at home and the installer just used small squares of clear rubber to ensure the space in the gap between the glass and the sill, wall and ceiling remained a constant thickness. Ultimately that is all you are trying to ensure, that the silicone remains at its ideal thickness to ensure adhesion while it sets (the ideal thickness - or the products limits, should be noted in the directions, as it was on the side of the tube of Dow Corning 795). The internet is pretty informative these days... you can easily look-up the products spec's.

If you also have an inner and outer layer deck layer, then I would also make sure that you seal the space between. I did this with West epoxy, buttered into the gap all the way around. To ensure that you're not continually pushing more in, first push a a small cord or rounded foam spacer to act as a backer. In my case it was less critical since I finished off the edge with the trim piece, and thickened my epoxy a fair bit. I also clamped the two together, but that may not be appropriate in your case.
Title: Re: Fixing leaking fixed portlights
Post by: Clay Greene on October 28, 2014, 08:35:39 AM
FYI, the Catalina instructions for replacing the windows is in the Tech Wiki. 
Title: Re: Fixing leaking fixed portlights
Post by: Stu Jackson on October 28, 2014, 12:27:00 PM
I added a link back to this in the Tech wiki under Port Lights & Hatches, and also to the "101 Topics" Leaky Portlights 101.
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on July 21, 2017, 12:06:49 PM
https://youtu.be/MQyjxVUskd8

Anyone tried this approach for fixed port rebedding using 3M VHB tape and the Dow 795?  I love the idea of the tape taking the mechanical load, but would love to hear about any experience you guys might have had for good or for bad.
Title: Re: Fixing leaking fixed portlights
Post by: Jeff Tancock on July 24, 2017, 08:29:41 AM
Looks interesting.
I need to do this project but procrastinating...........
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 13, 2017, 03:04:19 PM
I love the tape, but the approach didn't work for me... There isn't enough clearance between the edge of the lens and the fiberglass to get a good bead of 795.  I removed the lens... TWICE... from the VHB, which is quite tenacious!

I'd use this approach if I was cutting new lenses, which I'd make without the beveled edge.

For now, back to plan A. :)
Title: Re: Fixing leaking fixed portlights
Post by: DaveBMusik on August 13, 2017, 07:21:17 PM
Quote from: rmbrown on August 13, 2017, 03:04:19 PM
I love the tape, but the approach didn't work for me... There isn't enough clearance between the edge of the lens and the fiberglass to get a good bead of 795.  I removed the lens... TWICE... from the VHB, which is quite tenacious!

I'd use this approach if I was cutting new lenses, which I'd make without the beveled edge.

For now, back to plan A. :)

Which tape did you use? 5952, 5962 or something else?
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 14, 2017, 06:07:13 AM
I bought 5292, although I might get thicker next time.  Casey recommends 4991. (https://www.sailmagazine.com/diy/replacing-fixed-portlights (https://www.sailmagazine.com/diy/replacing-fixed-portlights))

To be clear, the issue wasn't with the tape.  That stuff is the bomb, in my opinion.  The issue is how tightly that lens (at least mine) fits into that opening.  There's no groove or gap around the lens, or not enough of one to matter, even with 2mm of tape ( I double mine up as an experiment) the beveled edge of the lens touches the fiberglass.

The technique would work fine if I cut the bevel off the lens but no need for that.  I'll figure out a way to hold those lenses in place and just use the 795.
Title: Re: Fixing leaking fixed portlights
Post by: Noah on August 14, 2017, 06:47:36 AM
If you don't put screws to hold it (at least temporarily) you could use a clamping fixture like Fred did.
http://c34.org/bbs/index.php/topic,7688.msg52834.html#msg52834
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 14, 2017, 07:35:56 AM
Thanks Noah (and Fred!)... That's the path I'm on. :)
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 21, 2017, 02:17:35 PM
I tried the wooden jig on the starboard forward fixed port.  I blame my execution rather than the idea, but let's just say it wasn't my best performance.  In the end, I believe it's resealed and, if you don't look too close, cosmetically adequate.

Both a dock neighbor and my local go-to boat maintenance guy suggested suctions cups so I tried that for the port window.  It went fabulous!
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 21, 2017, 02:19:45 PM
I apologize for the non-rotated images.  They show up on my phone and computer correctly.  Anyone know what I did wrong, speak up!
Title: Re: Fixing leaking fixed portlights
Post by: Noah on August 21, 2017, 02:32:31 PM
Suction cup are an interesting approach. My current ports have screws and I believe I will go with screws again when I do them this later year.
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 21, 2017, 02:34:11 PM
If I'd had screws, I'd definitely have kept them!
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on August 21, 2017, 02:35:49 PM
If anyone goes for suction cups... The following is a link to show you what I used.  Mine were $4.97 at wal-mart, however.

https://www.amazon.com/Peerless-3006C161PK-Mount-Suction-Chrome/dp/B005SQBZKK/ref=sr_1_fkmr0_1?ie=UTF8&qid=1503351301&sr=8-1-fkmr0&keywords=peerless+shower+suction (https://www.amazon.com/Peerless-3006C161PK-Mount-Suction-Chrome/dp/B005SQBZKK/ref=sr_1_fkmr0_1?ie=UTF8&qid=1503351301&sr=8-1-fkmr0&keywords=peerless+shower+suction)
Title: Re: Fixing leaking fixed portlights
Post by: Whiskymac on January 06, 2020, 01:31:56 PM
Sorry to resurrect an old post here but I am planning to to reinstall my aft windows/port lights
I read that a combo of the 3H VHB/Dow 795 is not recommended by those who have tried but I was wondering whether a 3H VHB/Butyl tape combo might work any better.? I was thinking the tape would provide the adhesion qualities needed and then if I ran a generous bead of butyl next to it it would provide the water proofing/gap filling qualities?
Title: Re: Fixing leaking fixed portlights
Post by: rmbrown on January 06, 2020, 01:47:57 PM
I think that butyl tape is the right material for almost everything... but not here.  problem is, with my windows anyway, that there's no mechanical fastener... If there were screws I'd use butyl tape and nothing else.

The VHB is a fantastic idea, and would no doubt work if you either had windows with 90 degree edges going into an oversized recess or if you had a tapered edge (like mine) and a lens that had more room around it.  My problem was that, once the old sealant was out, if you tried to put the lens in the hole, it was too big, IF you tried to get it near the bottom.  It was sized to have a pretty hefty bead of 795 underneath it and the stuff I had was maybe 1/8" thick... I even tried doubling it up, but it was too big, relative to the recess, to make good contact with the tape all around.  Thicker tape might well have worked.

While the tape may be strong enough to hold plate glass in a metal frame on a skyscraper, I have my doubts about it holding plexi to my fiberglass hull, and even more doubts about my ability to make it waterproof, so I just considered the tape as a "clamp" while the 795 cured.  When the tape failed, I got creative and held the lens in place a different way.
Title: Re: Fixing leaking fixed portlights
Post by: KWKloeber on January 06, 2020, 10:52:25 PM
Quote from: Whiskymac on January 06, 2020, 01:31:56 PM
Sorry to resurrect an old post here but I am planning to to reinstall my aft windows/port lights
I read that a combo of the 3H VHB/Dow 795 is not recommended by those who have tried but I was wondering whether a 3H VHB/Butyl tape combo might work any better.? I was thinking the tape would provide the adhesion qualities needed and then if I ran a generous bead of butyl next to it it would provide the water proofing/gap filling qualities?

The VHB doesn't have enough long-term holding oomph (for the butyl tape, which has to be held in tight compression (as in under a deck fitting) in order to not fail from weathering, etc.)

The way to go is 795 with the plexi temporarily held in place by internal suction cups, or external duct tape or wood blocking.  You don't need (in fact you don't WANT) compression during the cure - just held in place.
Title: Re: Fixing leaking fixed portlights
Post by: Whiskymac on January 07, 2020, 11:17:05 AM
Ok thanks for the reply.
Maybe I could use small pieces of the tape to hold window in place while the 795 dries as well as providing the spacing?
Title: Re: Fixing leaking fixed portlights
Post by: Jon W on January 07, 2020, 01:58:35 PM
Noah and I teamed up to remove and replace our fixed portlights. The toughest part of the job is removing the old in a good enough condition to be used as a template for the new portlights.

We used DOW 795 with small pieces of foam as spacers. The portlights were held in place with the screws from the originals while the DOW 795 cured.

According to Andy at Boatworks Today, VHB tape is the way portlights are installed on new production boats. The VHB has no forgiveness. That's why we used the adhesive/sealant spacer method.
Title: Re: Fixing leaking fixed portlights
Post by: Noah on January 07, 2020, 03:35:59 PM
I second what Jon says however, even when manufactures do use VHB tape to hold the windows in, they apply a bead of caulking on top—around the edge of where the plexi meets the fiberglas, to serve as a seal against water intrusion.