Sealing thru-deck fittings?

A

Ashley Lynn

New member
I have encountered a couple leaks and would like to know which adheasive/sealant to use.

I tried searching previous posts; however, I could not find reference to sealing the deck fittings.

I have found one leak on the starboard aft bow rail thru deck attachment and also on the port and starboard aft radar arch. I already plugged the oval hole on the outside of the radar arch...today-another puddle on top the galley. I would like to remove the radar arch and the bow rail and seal the bolts well. I would appreciate some advice as to what sealant to use....

This boat is becoming an obsession.

Thanks a million
 
Life-Seal works well. The trick is to:

1) Prep the holes with epoxy if the area is cored. This has been covered
extensively on this site recently, so I won't repeat it.
2) I usually tape the area off, lay out whatever I want to install, and trace or
cut out the area I want to bond. That way, I don't get caulk all over
the place.
3) Next, I come up with a way to attach the item but leave a
gap about the thickness of a quarter, maybe a dime.
4) Calk the object, the bolts, install, with shims (dimes, quarters).
5) Wait for the caulk to set up, then remove shims and tighten.
6) Cut off the caulk that squeezed out and remove tape. Use a good
tape that won't leave a sticky mess.

If you just apply caulk and tighten, you'll squeeze out all the caulk and
won't get a good bond.

Mike
 
I use boat life Life seal (a combination silicone and poly-urethane) only for plastic fittings where 4200 or 5200 would be a problem (not compatable with many plastics). I much prefer the urethanes (4200 and 5200) for SS fittings.

Agree that that any hole in the cored deck or cabin top, should be lined with epoxy. Remove the fitting. Drill out the hole so it is clean. If there is any water intrustion, use a Dremel tool and cut back any balsa core which is wet or shows signs of mold. Then fill this with epoxy and filler material, redrill the center of the hole to be snug, but allow the bolt to pass. If it is a small hole and not under compression, I just coat the sides of the hole with epoxy and don't undercut. Then clean the bottom of the fitting, the deck and the bolt with acetone. If any silicone has been used, it will be difficult to get a good adherence in the future. The best I have found for removal is the "MR Clean white errasors" Scrape the surface clean of any previous sealant.
Then apply 4200 or 5200 (perment) to the bottom of the fitting and the upper part of the bolt. Secure the bolt with an adequate fender washer under the deck or cabin top. Sorry to hear that there are still leaks appearing!
 
Bob, do you ever find that items bedded with 4200/5200 rip out the gelcoat
should they need to be removed at a later time? This fear is why I don't
usually use 4200/5200 above the water line. Perhaps it is an ungrounded
fear...

Mike
 
Mike,
I have been using 5200 for over 15 years and 4200 for over 10 years. The only time I had any problem with damage to gel coat, was in a boat where plastic port lights had been set in with 5200. I had to remove them. At first I used a broad chizzel--and damaged the glass under the flange. After that, I used antibond, or hot wires (which I had used in other instances) and not had any damage. But I consider 5200 to be permenant. So if it is an item I may have to remove I use 4200. I have not seen fiberglass damage from the 4200. 4200 has half of the adhesive power of 5200. Of course, fiberglass can be repaired if damaged--it is easier to repair than water in the core of a deck--and that is why I make this choice.

Bob
 
I stopped the leak from the radar arch. However, I still have a leak that accumulates water in the forward starboard storage area....under the captains feet area.......I believe it may still be coming in from the bow rail thru hull fittings.

I will try again.
 
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