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Old 31-08-2010, 05:34   #1
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Bedding Genoa Track

When bedding the deck mounted Genoa tracks, should you apply sealant to the whole track, or just the through bolts? I understand one builder of high quality boats just seals around the bolts, making it easier to clean under the track. Also, what is the Sikoflex caulk that is recommended?
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Old 31-08-2010, 07:14   #2
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Any equivalent adhesive caulk to 3M T5200 will work. Only the mounting bolts need to be caulked - but - each bolt must be surgically clean by either using new or thoroughly cleaned old bolts, washers, lock washers and nuts. They should be wiped with acetone to remove any grease. Do not touch the bolt except at the top rim of the head as finger grease will prevent the adhesive caulk from grabbing the bolt. One little trick I use is to first put a little Anhydrous Lanolin (Lan-o-cote) worked into the threads of the bolt before applying the adhesive caulk.
- - The hole should be "reamed" to remove any old caulk and get the fiberglass as clean as possible both around the top surface of the hole, the inside of the hole and the bottom surface. The bottom surface is the real bitch to access and clean.
- - I also - after the bolt is inserted into the hole - use a fender washer with a ring of adhesive caulk on one side before assembling the lock washer and nut. The fender washer is like a mini backing plate but more importantly the ring of adhesive caulk is squeezed up against the bottom surface of the hole through the hull.
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Old 31-08-2010, 07:41   #3
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Sikaflex 292 is Sika's Structural Polyurethane Adhesive Sealant, roughly equivalent to 3Mís #5200.
Sika Corporation | USA
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Old 31-08-2010, 07:48   #4
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5200 for genoa tracks???? WOW, what if you ever want to remove the tracks?

I plan on using butyl tape to seal the tracks and let the bolts & backing hardware do the work of fastening & holding the tracks. Butyl will remain pliable for 20 years yet is easy to remove as it is not a fastener, only a sealer...a damn good one.
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Old 31-08-2010, 08:32   #5
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Silkaflex 292 and 3M 5200 would be the least logical bedding compounds to use on a genoa track. These are adhesive/sealants, with much more weight on adhesive side of things, then sealant. This isn't a bedding compound, it's a glue that seals.

What you want is a sealant, maybe one with slight adhesive properties. 3M 101 (a polysulfide) or similar will have considerably less adhesive qualities, but very good sealant properties. SilkaFlex 291 LOT if using Silka products.


Do your self a favor and put anti seize on the nut's threads (not the bolt or machine screw) before you run it home, which BTW should be done slowly, by hand to prevent galling.

Another common trick is to counter sink the holes where the fasteners pass through the deck, on the deck side. With bedding in place, the counter sinks will form a nice "O" ring around each fastener, when dogged down, effectively sealing each.

Yes, bed the full length of the track, so there are no unsupported areas.

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Old 31-08-2010, 08:41   #6
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I think 4200 is what you want, or BoatLife life-calk

I have used butyl tape for other hardware. Don't know if it would be good for a track though because I haven't tried it.
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Old 31-08-2010, 09:01   #7
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Originally Posted by gettinthere View Post
5200 for genoa tracks???? WOW, what if you ever want to remove the tracks?. . .
That is exactly what your want. Never to have to remove the track because of leaking mounting bolts. Only the strongest adhesive caulk will resist the twisting and flexing and cooking in the tropical sun. There is a reason why the major boat manufacturers use very strong adhesive caulk - they don't want to be flooded with bitches about leaking track bolts. Which you cannot get to in most boats without removing all the interior sidewalls and furniture, etc.
- - Boats flex like crazy while underway in the oceans and seas. Normal non-adhesive caulks will peal away and allow water to migrate down the bolt shaft. However, for things that are normally expected to be subject to removal like glazing/plastic ports and windows, etc. then a good caulk is definitely called for. And even 5200, et.al., will not adhere well and be no better than normal caulk if the surfaces are not absolutely clean.
- - As to caulking the whole track, that is simply a personal decision since water migration under the track can cause corrosion problems with the track if water without oxygen gets trapped. Aluminum track has less problems than stainless steel track in this department. Tee-track is easier than flat bar track which needs to be elevated so that the cars can slide down the track. Some use teak for the spacer under flat track but I built a mold on the deck edge and made a fiberglass spacer to keep the flat track elevated. 20 years later there are still no leaks nor the need to remove the track.
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Old 02-09-2010, 07:30   #8
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It's an incorrect assumsion that you want a tough, very adhesive bedding under a sail track. The fasteners hold the track, not the sealant and if you have to rely on the sealant in any regard for strength, you surely don't want something like 3M 5200 or similar.

The reason production builders use these products is very simple, it's a polyurethane and therefore rather inexpensive in comparison to other products.

Yes, boats flex, which is why the track is very stiff, the fastener spacing tight and the fasteners of substantial diameter. The bedding has absolutely nothing to do with the ability of the track to stay in contact with the boat. Suggesting such is purely ludicrous, given the particular physical qualities of the adhesive/sealants compared to the fasteners and track! If this was the case, the tracks would be epoxied down with a substantial flange and married to the deck, which of course denies easy repair, alteration, removal and upgrading.

Caulking the length of the track prevents the track from sitting up on little isolated mounds of smashed caulk, which (in between) will just be dirt and debris catchers, promoting corrosion. It also causes point loading at the fastener holes on the track, so go ahead and put little daps of caulk if you want, but when cracks show up years later, you'll know why. The idea is to get the track completely flat against the deck and the fasteners prevent movement. Seal the track to the deck for the track's sake and to prevent the fasteners seeing any moisture ingress. In most cases where movement is seen, the whole area surounding the track, deck and all are moving, which is an engineering problem, not a bedding issue.

Osirissail is absolutely correct in that the deck and track must be sanitary clean. Most manufactures use a solvent wipe, just before sealant application to insure the surfaces are goo free. This is especially true if you have multiple pieces to the assembly like a spacer.
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Old 02-09-2010, 08:42   #9
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I would not use 5200 either. The track, at some future date, will have to be removed and 5200 would be extremely hard to remove.
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