|Topic Review (Newest First)|
|04-18-2008 12:33 PM|
|sailingdog||The concave recess isn't all that critical if you've countersunk each of the fastener holes slightly.|
|04-18-2008 11:26 AM|
Well Halekai...as usual, you present a very convincing case based on experience. I've had good luck re-bedding MT genny tracks with the 2-step method...perhaps due to overkill on the 4200...perhaps luck...
Will give your way a shot the next time around...but I don't recall concavity on the bottom of my track so will have to check that first as it seems critical.
|04-18-2008 10:17 AM|
I see Butyl tape as a great solution to a port window. But I still don't see it being used on a traveler where there is flexing and pressure placed upon the hardware.
Not having Butyl tape fail in 29 years on a stationary port with little stress placed on it is far different from deck hardware with pressure and all sorts of pulling being placed on it.
|04-18-2008 09:55 AM|
Just a follow up to the Butyl question. Yesterday I began removing my Beckson port lights to replace them with stainless ports. These ports were OEM installed, and of the eight, only one leaked. Each and every one of these ports was installed with butyl and only one of them had leaked in 29 years!
My new port lights will go back in with butyl and a little Sikaflex around the UV exposed edge and a bevel around the ports opening for capture of the butyl that will be better than factory!!
P.S. The gray colored butyl was easy to break free and still just as sticky as the day they were installed! I removed four port lights yesterday in an hour and a half and that included cleaning the surface and prepping them for the new ones.. That would have NEVER happened with Silicone or polyurethane...
This is the first time I've come across 30 year old butyl and to say the least I was VERY, VERY impressed that it's characteristics remained virtually unchanged!! Polyurethane at 30 years retains very little of it's original elasticity...
|04-15-2008 02:39 PM|
To properly execute a two step tightening you need to know the exact condition of cure and that's nearly impossible due to temp and humidity differences. If it's to dry, and past prime tightening time, you'll likely break the seal between the bolt and the sealant by twisting it. This break between bolt and sealant will allow water ingress. If it's still to wet, the curing sealant, then what's the point? To get this two step process "just right", as in, not to hard not to wet, is nearly impossible especially for those who don't fully understand cure characteristics of the individual sealants available.
I won't even address Jeff H's suggestion of soft rubber washers under a genny track because I'm still nursing the wound from falling off my stool reading that one..?????
I learned a long time ago, from the masters at Hinckley Co., how to properly bed and it DOES NOT include a two step process no matter what Don Casey says.
My boat yard laughs at this "two step" method/wives tale/urban ledgend, all the way to the bank..!! I was just talking with them last week about a deck job they did at a cost of 28K. The owner used a two step process and broke the seal at over 80% of the fasteners on deck.. The boat had been surveyed at about 95% dry four years before he then decided to re-bed.... 28k later... Need I say more?
Unless you can guarantee that you will absolutely, positively, 100% NOT budge that bolt during the 2nd stage of tightening, after a period of cure, DO NOT use the two step process! I'm convinced this is, or was, a process created by boatyards and industry insiders like Don Casey, and such, for future industry revenues of deck repair. It is my guess that the majority of wet decks are caused by poor bedding techniques, including, but not limited to, the "two step"..
Countersinking, is and a full tightening, is enough trust me!!! In over 18 years of using the bevel/countersink and single step tighten method I have NEVER once had a re-leak. When I say this I use the photos bellow as evidence to support eh bevel/countersink and one step tighten method. Oh, and I've also NOT used 5200 in those 18 years either.. That's another wives tale for another day and thread though...
The pad eye bellow was installed on my AB RIB using the countersink/bevel method with an immediate and full tightening and "squeeze out" as you call it. It is now 6 or 7 years old and has NEVER, EVER leaked even one drop of water! The big clincher here is that these fittings are BELLOW THE WATERLINE and are used to lift my RIB into the davits so they do see stress and full immersion bellow water something your stanchions or genoa tracks certainly will NEVER see for more than a few seconds or so.....
#1 point: Most genoa tracks, from most manufacturers, have a concave bottom to allow a sealant bed. They are designed this way for a reason! Please note the bevel or concave contour on the bottom of this Schafer track it's there by design to help capture and retain a bead of sealant!!
For installing genny tracks counter sink the deck side of each bolt hole slightly, just enough to creat a 1/16 of an inch 101 o-ring around the bolts shank. Then use some shims to hold the track off the deck. Apply a ring of sealant to the head of each bolt as you drop them into the track holes one by one. Next, run a bead up and down each side of the track (this shims are holding it off the deck so yoo can get under it with sealant) becareful to get plenty around each bolt. Once the sealnt is in place pull the shims and let the track settle under it's own weight. Now climb inside and begin spinning on the washers and nuts. Using a rechargable impact driver to tighten the bolts allows you to do it as a one man job from inside. Once everyhting is tightened down go out side and using a plastic scraper, a trash can (with liner) and LOTS of paper towels or rags clean the excess sealant that squezed out with what ever solvent the manufacturer recommends. If it's 3M 101 Acetone is fine if it's a polyurethane like Sika 291 or 4200 use what they recommend. The fittings bellow were cleaned up this way and it looks clean and neat..
P.S. My thru-hulls are also installed with a single step tightening and I've also never had one I've installed leak and I've installed LOTS of underwater fittings having worked in a boat yard in my younger days....
|04-15-2008 02:24 PM|
Cam - I am rebedding all hardware in the next couple weeks. Re: your advice of not tightening until cured - Is that necessary when you bevel out all of the boltholes, to hold more sealant - forming an O-ring?
Jeff - Similar question - If you bevel out the bolt holes, do you feel it is still necessary to add rubber washers, to increase the amount of sealant?
Thanks in advance!!
I have read many posts, as well as Don Casey's advice, on the subject, but was leaning to Halekai 's method of bevelling - and tightening all at once!
|04-15-2008 01:49 PM|
I have been experimenting with butyl tape. So far I have gotten very good results. It works especially well on tracks where you don't want goop oozing out and clogging the tracks. I used the grey rather than black butyl since it does not bleed as bad as the black. One minor point, I did use Sikaflex on the bolts when I inserted them, since I was not all that confident in the adhesion between the butyl and the threads of the bolts.
If you do go the Sikaflex caulk idea for bedding the tracks, I suggest that you insert a soft rubber washer that is larger than the bolt at each bolt hole to act as a spacer so that you end up with a caulking bed that has some thickness to it.
|04-15-2008 01:36 PM|
BTW, welcome aboard
|04-15-2008 01:19 PM|
|camaraderie||Gil...bad idea. Butter away being sure to get the 301 in the bolt holes and NOT to tighten fully until it is well set so you don't squeeze it out of place.|
|04-15-2008 12:53 PM|
|Freesail99||I used sikaflex 291 when I did mine. The reason I used sikaflex is because the product allows a certain amount of flex, before it will break it's seal. I also looked at using 4200 but when compaired to sikaflex and it's ability to flex, I thought the sikaflex 291 was the better product for the Genoa track. It does take a few days to firm up and shouldn't be used before it does.|
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