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**s/v Jedi** · 25-04-2013, 14:41

Quote:

Originally Posted by Swift Drift

Thanks for the feedback. regarding the screws turning loose (backing out).... how are you going to solve? Locktite? Filler in screw holes? Curious to know.

I had no incentive to take it off, clean up all the butyl, and start over, so I took a lame way and put pieces of bamboo skewers with 5 minute epoxy in there, let it cure for an hour, then drilled the first hole and the screw again didn't grip. These are hefty screws. I then proceeded next hole to put the screw in without any drilling, which went surprisingly well and it was good.

Still not happy; the next hatch, I will drill out the holes and fill them with epoxy plugs using high density filler so that I can tap for machine screws

If I ever have time left, I'll redo this hatch

belizesailor · 26-04-2013, 06:08

Quote:

Originally Posted by GordMay

Butyl, similar to Silicone (but less contamination problems) has little adhesive strength; so works best as a type of Gasketing material, where it’s installed under compression; such as when through-bolted.

3M “5200" & “4200" both have strong adhesive qualities, which will enhance their watertightness under less compressive installations.

Maybe in "a less compressive" application (example?), but the problem Ive seen w 5200 is that it cures relatively hard and the as the hull works little bits let go and you develop leaks...on a fitting that is now agressively adhered to the deck...bitch to remove and rebed (BTW 5200 has relatively poor chemical resistance so pre-apply a mild solvent helps a lot).

My take is that for hardware which is already bolted or screwed in place you dont need an adhesive, but a good flexible sealant....like 4000UV or butyl which remain flexible and are thus less likely to develop leaks. Also when time comes to rebed it is easier. I think either one or some combination will work fine for the OP.

**roverhi** · 26-04-2013, 09:46

Quote:

Originally Posted by GordMay

Butyl, similar to Silicone (but less contamination problems) has little adhesive strength; so works best as a type of Gasketing material, where it’s installed under compression; such as when through-bolted.

3M “5200" & “4200" both have strong adhesive qualities, which will enhance their watertightness under less compressive installations.

Butyl doesn't have the adhesive strength of 5200 but it doesl stay stuck. Try removing a part that's been bedded in butyl. It will pull up with the butyl desperatately clinging to both the part and the surface. When I say clinging it's like pulling apart bubble gum not the glue like bond of 5200. It remains flexible and bonded so will move with the surfaces not breaking the seal. Big negative with butyl is it's not petroleum resistant. Use paint thinner to clean up and it turns into a slurry. It will stain porous old gel coat, mine was 40 years old, but hasn't been a problem with the LPU paint. Best to peel it off and, since it instantly bonds to itself, use a glob of waste butyl to get up the small remnants.

Do that with with sillycone and it will pull off like a formed gasket not adhering all that well to either surface. That's the reason that sillycone is such a crappy sealant. Once it breaks the bond with whatever it's supposed to be sealing, and it will, it's leak city. Sillycone is also a bitch to clean up. It skins quickly and it resistant to chemicals so doesn't want to come off the surrounding areas. We've all the seen the brown crud around something sealed with sillysone that that wasn't completely cleaned up. I used it to seal a sink in my home and took more time trying to get the sillycone off the sink and counter than it took to install the sinck, plumbing and all. Sillycone is the spawn of the devil unless you are into strip bars.

LifeCaulk is polysulfide. It is a great caulk that doesn't harden. Have pulled up stuff sealed with it after 30 years in the Hawaiian Sun and it's still pliable. It does act as a semi adhesive so will pull up poorly adhered finishes and wood grain if you use brute force. When I have to remove stuff sealed with it, use slow steady pressure. Usually force putty knife or chisel partially under the piece and wait. Have also used a halyard or tackle to apply steady pressure where appropriate. The part will lift off after a few minutes.

thinwater · 26-04-2013, 11:15

Butyl.

My boat came factory with all of the deck hatches with butyl, and when time came to re-bed (broken glass) I thanked them. A 20-minute job, start to finish, with no leaks before or after, and I've done a bunch. Don't believe that there is no adhesive quality; it sticks tenaciaouly and you will have to work a blade through all of the surface. But you also won't risk breaking anything. Unlike harder caulks, it will move with the hull. I 've never had a leak with butyl (leaks with other dried out caulks, yes), not on 25-year old boats; rebedding has always been for other reasons.

I'm sure this depends on the solidness of the FRP, the location of the hatch, and the use of the boat. I'm sure it depends on the butyl (there are some terrible latex products out there--you want the sticky silly putty sort. If near the waterline or critical to water tight integrity, I can't think a rational reason not to through-bolt. But for the OPs deck hatch, butyl makes perfect sense.

NorthPacific · 27-04-2013, 22:14

Crap just replaced a large window with B. Tape. No other fastenings.

belizesailor · 28-04-2013, 14:00

Quote:

Originally Posted by belizesailor

Maybe in "a less compressive" application (example?)...

Ha, found an example of course shorlty after posting this...old tooth brush holder in head aparently was stuck to the gel coated wall w 5200. Never use it so thought I would just pop it off...yeah right.

goboatingnow · 28-04-2013, 16:09

Why now consider using the newer silane based modified silicones. They solve a lot of the issues of older silicones but without the overly strong bonding of polyurethanes.

I've never used polyurethanes for bedding after one episode where the gelcoat come up with the adhesive ! I've use poly sulphides, Butyl and latterly silanes. I once stick down a whole teak teak with Polyurethanes . Hasn't budged in 20 years.

A good seal is like a gasket. It doesn't need to be an adhesive at all
Dave

Boulter · 28-04-2013, 20:40

Quote:

Originally Posted by s/v Jedi

I think the butyl tape is fine, but I had a problem with the screws turning loose. You better check that before applying butyl

I just today took off my turtle (I think it is called) over the companionway. It was fastened with 1/2 inch screws. My core is wetter and more rotten here than anywhere else I have yet found. Clearly inadequate for something that is stepped upon, as are hatches. The replacement hardware will be through bolted, even though my forehead is going to occasionally strike same.

Boulter

**roverhi** · 28-04-2013, 20:53

Doubt it was the caulk that caused the problem but the installation. Butyl is especially good for something that flexes because it gives so much and never hardens. No reason to through bolt though unless the screws stripped out. Even then, use a dremel 199 bit and rout out the core around the fasteners, fill with epoxy thickened with 404 West systems filler or equivalent, drill and tap the holes for machine screws or use self tappers and you are back in business.

Aloha
Peter Ogilvie
'Ae'a, Pearson 35 #108

Swift Drift · 28-04-2013, 23:34

So just returned home from my 3 day boat work marathon at the boatyard that is 300 miles away. I am pooped from busting my butt on projects from sun up till 2:00 am, but I wanted to get as much done as possible and I did!

I am pleased to report that the hatches are all bedded with butyl and all screws are in solid! No leaks upon testing and I have the utmost confidence in the butyl install long term. Will report back should any issues arise, but I doubt they will.

Thanks for all of the input. Splashing the boat in 2 weeks.... Can't wait to go sailing! I feel like a zombie and am going to sleep now.

tybee22 · 29-04-2013, 02:00

Beckson recommends only silicone for thier ports. Just bought 2 new and the installation instructions were very clear on that. There are high grade silicons that are paintable.

Swift Drift · 29-04-2013, 17:14

Quote:

Originally Posted by tybee22

Beckson recommends only silicone for thier ports. Just bought 2 new and the installation instructions were very clear on that. There are high grade silicons that are paintable.

I used butyl for my Beckson ports that go through from cockpit to aft stateroom as well. We'll see what happens but I'd be shocked if I developed leaks. Regardless of what Beckson recommends, at the end of the day you are working with two surfaces: plastic ports, and a fiberglass hull. I can't think of any reason why butyl would not work even if Beckson doesn't recommend it.

NorthPacific · 29-04-2013, 20:25

So next weekend I am going to replace the head hatch glass. Again. Had 2 Pro shops have a go and as soon as it is walked on it leaks. So the Mrs is going to have a go with the Butyl stuff. The large port (window we installed has not leaked so far, with rain snow and sleat for 2 weeks so here goes again.