|Topic Review (Newest First)|
|11-24-2011 05:41 PM|
Once again, thanks very much for the input for this thread. For anyone else contemplating a similar repair, the messages make an excellent "how to do it" work plan.
I would like to add a few points. My first attempt at it was unsuccessful because I didn't use enoughput tape and/or because there were pits and holes in the fibreglass cabin side. These weren't easily noticed but probably contributed to the failure of the first attempt. I removed the portlight once again (warming with hairdryer really helped), cleaned up, filled the pits etc. with gel-coat micro-balloon filler, smoothed everything and then reapplied the butyl tape at double thickness. I put one strip on the fibreglass around the opening and another one on the aluminum frame. Trying to add a layer of tape on top of another layer of tape was a little tricky as the tape sticks to tape very well and is difficult to move if you make slip during application.
Since it was quite cool on the day I was working (~45 degrees F. ), I used a hairdryer to soften the tape while I was re-applying the screws. Worked very well.
One warning about this kind of job is that if the inner frame screws directly to outer frame (not through-bolted) you have to make sure that you have enough tape at the joint that it will actually squeeze out the edges before the screws bottom out. This just barely happened to me and I think I would have been ok, in my case, with perhaps a third layer of tape, though it might entailed doing a lot more clean up afterward.
Cheers and thanks again for the help,
|09-30-2011 04:41 PM|
Some auto windshields are sealed with a butyl "rope" rather than a flat tape. Black, gooey, sticks and conforms and fills gaps.
I'd suggest a visit to an auto body or glass supplier, ask them about the butyl rope and about the urethane or other adhesives they use with it, to bond windshields.
You don't find the good stuff in RV stores or Home Depot.
|09-30-2011 01:16 PM|
Originally Posted by MastUndSchotbruch View Post
|09-30-2011 11:55 AM|
Thank you all, very, very much for your contributions, responses and suggestions. I am now actually looking forward to the project instead of dreading it.
Cheers and thanks again,
|09-30-2011 12:31 AM|
I recently re-bedded my through bolted ports with butyl, worked well. We have had a few big fall rainstorms with no leaks yet. Most of the points have been made, but...
I agree with "cutting" the butyl ooze with a putty knife prior to the stab and pull step. Otherwise there is a tendancy to pull some butyl out of the seem.
Get all of the old stuff off, it will be hard if it is silicone. I used Mainsails method of a sharp chisel used very carfully at a low angle to get it off the gelcoat followed by wet sanding and a final solvent wipe.
Use lots of butyl, it is cheap. It will slowly ooze into the nook and gaps if you do it on a hot day and go slow. It is much easyer to clean up than most caulk.
The stuff sold through his compass marine site really is better than what was available at my local RV dealer. It is the proper thickness for port work and although stickyer, is easyer to handle because of its size and packaging. I found that the corners of the ports tended to get starved of butyl, and a double layer helped, the strait sections did not need as much, your milage may vary.
|09-29-2011 11:51 PM|
|MastUndSchotbruch||Yes, I am glad you agree. In my situation it is hard to apply pressure which makes butyl an inefficient choice. Live and learn!|
|09-29-2011 07:05 PM|
Originally Posted by MastUndSchotbruch View Post
I've bedded lots of chain plates with butyl, and none have leaked, but I choose them carefully. I don't however use butyl on all chain plates and base my decision for its use on the particular design I am working with.
The original chain plates on our CS lasted 31 years without leaking. I only pulled them to inspect them. I then rebedded them with butyl and they've been bomb proof. Our chain plates are a different design though and the plates are through bolted...
Butyl is not always ideal for every bedding situation so don't let one situation get you down on it.
|09-29-2011 06:08 PM|
not so much luck with chainplates
Hm, to add a negative note, I rebedded all my chainplates with grey butyl tape but most of them are still leaking. The holes in the deck where pretty big (chainplates not well fitting) and it was hard to exert enough pressure with the cover plates to squeeze the tape into shape (the plates are held by small screws). I am considering taking them all out again and redo with polysulfite. Big disappointment!
|09-29-2011 05:59 PM|
|ilikerust||By the way, make sure you remove every last bit of that old sealant - it does sound like silicone, based on your description. I used a utility knife blade to scrape away all the old adhesive from the aluminum frame and the perimeter of the fiberglass opening, followed by sandpaper to really get it clean, followed by a solvent wipe.|
|09-29-2011 05:56 PM|
I have the same port lights, if I'm understanding your description correctly, on my 1968 Pearson. I re-bedded two of them that were leaking, using butyl tape, after reading all of Maine Sail's excellent tutorials. The previous owner had bedded them in BoatLife stinky caulk. What a stink that made, scraping all that crud off!
Anyhow, it worked extremely well. Nary a drop since.
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