P42 fixed port light replacement / reseal

eianm

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Jul 7, 2010
517
Hunter 42 Sydney
I finally got around to removing my starboard side fixed port panel to re seal to overcome a small but persistent leak.Getting the panel out was easier than expected. I found the factory had used a combination of a butyl barrier and then the Dow 795 as the bond and seal.Chased around for ages looking for butyl tape but was repeatedly told they now use UV stabilised foam double sided tape, so ordered that.
I guess I simply wanted to ask of those who have done this job, do you have any advice on mistakes to avoid, or tips on getting the best result please. My biggest question is how much 795 / what size bead to lay down??
Cheers!
 
Last edited:
Jul 25, 2004
359
Hunter 42 currently in New Zealand
Hi Eian,
I've done that job more than twice, and I STILL make the same mistake (and now have to do it again). Fortunately it's not too big, tedious, or time consuming a job. My mistake is that I always tighten down the screws (that hold the port to the fiberglas) too tightly and squeeze out too much 795. The NEXT time I do this job I will just screw in the screws enough to get a very minor bite on the thread and then let it dry. Mine have leaked because I didn't leave enough 795 in there.

I recently watched another boater do his side ports, and he didn't even use screws. He set up a couple of diagonal boards to hold the port in place while the 795 set.

I always go overboard with masking and dropcloth covering for everything, since 795 likes to find its way all over the place. Then I lay a ridiculously large bead and end up tossing some 795 away from all edges. I see it as cheap insurance against having to do the job too soon once again . . . . I've seen some people use spacers in between the fiberglas and the port to protect themselves from squeezing out too much 795. I might try that one time to see if I can protect myself from myself.

I did my large front windshield last year and purchased a case of 795 plus three more tubes. I used the case of 12 but not the three extra tubes. I was listening to my co-worker (and more able engineer friend) who kept telling me I was using too much. When the job was done I could see that on the inside we didn't get a complete coverage all the way to the edges of the fiberglas bed (and we applied a decorative bead to cover that). The savings on the three tubes is something I'll kick myself for the next time I re-do that windshield for leaks. . . .

Stay safe and healthy,
Paul
 

eianm

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Jul 7, 2010
517
Hunter 42 Sydney
Finally completed the job -have to admit though, after doing all the prep very thoroughly,i got cold feet re not having any idea how much 795 to lay down , nor exactly where tolay the beads, so i asked our marina shipwright if he would help me- took him 15>20 mins and i have a perfect job, plus i am not confidant to attack the job myself next time! I used your suggestion Paul,in only just starting screws and then going back and tightening very carefully 3 days later( shipwrights suggestion).
The time taken to mask up very carefully before hand is certainly worth it .
 
Dec 25, 2000
5,703
Hunter Passage 42 Shelter Bay, WA
Thanks for the tips, Eian. Do you use the opening Bomar port lights as were the original?
 

eianm

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Jul 7, 2010
517
Hunter 42 Sydney
yes- all totally original spec- I should mention- originally they used a butyl mastic tape bead inside the 795 bead, so i used a special 3m glazing double sided tape of 1.6mm thickness, i ran an entire seam around the whole panel- in line with the 7 retaining screws- i very carefully notched out the screw holes out of the double sided tape bead without breaking the constant seal, so effectively , i have two separate but complimentary sealing beads.