seattleboatguy
Senior Member
I need to re-bed this plastic window frame on the side of my Marine Trader. What type of caulking would you recommend? Is there any way of preventing the leftover caulking in the tube from turning into a brick?
re-bedding outside window frame
- Thread starter seattleboatguy
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Your photo shows a lot of dried out cracking chalk around the the window flange. I’m wondering if whoever installed the window used the same chalk under the window flange and it has failed. If so the fix would be to remove the window and use butyl chalk under the flange. The bead of chalk around the exterior should be more cosmetic than a way to waterproof the window.
firehoser75
Guru
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Caveat, I am not an expert in this area, but I have replaced a plastic Beckson porthole on my Nordic Tug.
According to Beckson and NT, the porthole had to be completely removed with everything cleaned up WELL. Then they recommended the "dreaded" clear silicone as the product of choice FOR PLASTIC. Not your home store kind of silicone but a specific product. Dow 795 or Boatlife Marine Silicone. Other sealants can react with the plastic according to Beckson.
I strickly followed their directions, and my porthole went in fairly easily, with no leaks and is still not leaking 2.5 years later. Not a long time, but that is all the experience with this type of replacement (plastic port using silicone as recommended by the manufacturer). Hope that helps.
According to Beckson and NT, the porthole had to be completely removed with everything cleaned up WELL. Then they recommended the "dreaded" clear silicone as the product of choice FOR PLASTIC. Not your home store kind of silicone but a specific product. Dow 795 or Boatlife Marine Silicone. Other sealants can react with the plastic according to Beckson.
I strickly followed their directions, and my porthole went in fairly easily, with no leaks and is still not leaking 2.5 years later. Not a long time, but that is all the experience with this type of replacement (plastic port using silicone as recommended by the manufacturer). Hope that helps.
Lou_tribal
Guru
I used Sikaflex 291 LOT to do the same job and I am very happy with the result.
If I can give you some advice it would be first to be well prepared and setup with rags etc and to be focused and careful at what you are doing. Caulking can easily become a big mess when you start putting your fingers in it by mistake.
To collect excess take a piece of tube (like pex tubing for water) cut in beveled (like cutting it at 45 degrees) and slowly pass it along the edge, the tube will collect extra caulking in it.
I used WD40 degreaser (not the lubricant) to clean what was left while fresh.
L
If I can give you some advice it would be first to be well prepared and setup with rags etc and to be focused and careful at what you are doing. Caulking can easily become a big mess when you start putting your fingers in it by mistake.
To collect excess take a piece of tube (like pex tubing for water) cut in beveled (like cutting it at 45 degrees) and slowly pass it along the edge, the tube will collect extra caulking in it.
I used WD40 degreaser (not the lubricant) to clean what was left while fresh.
L
firehoser75
Guru
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- Canada
- Vessel Name
- former owner of "Pilitak"
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- Nordic Tug 37
Lou,
I use Sikaflex 291 or 295 quite a bit for other sealing purposes (and like it alot), but not for plastic parts/windows. If I remember correctly, even Sikaflex (the company) does not recommend it for that purpose?? but my old memory could be failing me in that regard.
If the port was bronze or stainless, I would recommend either the Sikaflex or Butyl tape, based on what I have read (from "experts") and the experiences that I do have.
I use Sikaflex 291 or 295 quite a bit for other sealing purposes (and like it alot), but not for plastic parts/windows. If I remember correctly, even Sikaflex (the company) does not recommend it for that purpose?? but my old memory could be failing me in that regard.
If the port was bronze or stainless, I would recommend either the Sikaflex or Butyl tape, based on what I have read (from "experts") and the experiences that I do have.
Lou_tribal
Guru
It was an aluminium frame for me so you may be right, did not check for plastic, good catch!
L
L
FF
Guru
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Rebding items is better a PM job than a leak cure repair.
Windows , ports ,hatches, deck fittings , stanchions windlass, all need their goop replaced at an interval.
Its old style but Dolphinite is the easiest to use , as the old stuff cleans off easily , and any that squishes out is also easy to clean.
The roll tape with sealant from the RV and house folks also works well, but is best for sealing items built to use it.
Windows , ports ,hatches, deck fittings , stanchions windlass, all need their goop replaced at an interval.
Its old style but Dolphinite is the easiest to use , as the old stuff cleans off easily , and any that squishes out is also easy to clean.
The roll tape with sealant from the RV and house folks also works well, but is best for sealing items built to use it.
boathealer
Guru
I am a big believer in (and user of) Butyl tape. Has been flawless so far on ports, windows, stantions, and more. Cleanup a breeze, easy hardware removal when needed. I use Compass Marine's version - https://pbase.com/mainecruising/butyl_tape (no ties).
seattleboatguy
Senior Member
I've never used Butyl tape, but I see it used often on the boat repair YouTube channels, so maybe I'll give it a shot. HiDHo had a reply similar to yours, but he mentioned Butyl "caulk". I checked amazon, and there does appear to be Butyl "caulk" that comes in a tube. Is the "caulk" and the "tape" pretty much the same thing?
Comodave
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I use butyl tape with things that can be bolted down. It takes a lot of force to squeeze the butyl tape. With plastic I am not sure that butyl would compress properly without cracking the plastic. I replaced 11 plastic portholes with cast S/S portholes and used butyl. I had to use clamps to squeeze the portholes tight.
