Sealant for C/B case - keelson

[JimJ]

What would be a good product to seal the joint between the bottom of the centreboard case and the top of the keelson.

It is wood to wood joint. The C/B case is held down by 7 bolts on each side at 9" centres.

I would prefer something that would enable the removal of the C/B case in the future.

It appears the former sealer was like "white lead"

Any suggestions?

[Scott Rosen]

I would use 3M 4200 or one of the lower-adhesive Sikaflex products. White lead can get brittle when it dries and will crack and let water in.

[JimJ]

I would like a product that would enable me to remove the C/B case in the future if needed.

I suspect that 3M 4200 or Sikflex 291 would not allow this considering the surface area to be sealed although the data on 4200 indicates that it will allow dis-assembly.

I was thinking of a thin gasket of neoprene.

[Dave Hadfield]

Jim, how critical is this, ie, how big is the boat and will it be stored in the water?

[JimJ]

Hartley TS 18 and stored on its tralier. We use the boat all year as we don't have an winter season here as such.

[Dave Hadfield]

No winter! Hmphhh!

Well, if it's not going to sit on a mooring with you away from it, why not? There's nothing to lose. Sure, try it with a gasket. You're thru-bolting anyway.

Is it that you might modify the boat and take out the CB later? Or shift it fore or aft? Otherwise I don't know why you wouldn't want it more permanent, using 4200 as Scot suggests.

Mind you, CB maintenance would certainly be simplified if you could easily remove the trunk....

[Scott Rosen]

If the sticky-flex is too sticky for you, then use an old-fashioned linseed oil bedding compound. I use Interlux Boatyard Bedding Compound for bedding things that I will be removing frequently and that don't require a strong adhesive. When I bedded the trunk in my dinghy I used 5200, figuring it would be a lot of years before I would be removing the trunk and I wanted the strong adhesion.

Different boats, different longsplices, as one of the Ians likes to say.

[ 01-23-2003, 09:03 PM: Message edited by: Scott Rosen ]

[JimJ]

Seeing that the plans for the boat have the C/B bolted to the keelson, my reasoning is that at some stage one would need to be able to remove it. i believe that this is the second time that it has been out.

The remains of the compound that was sealing it until I removed the C/B case was a white substance that had gone hard but was doing the job and not letting any water in. It scrapped off quite easly.

Considering that it would be at least 10/12 years since it was last removed and most likely te same time before the next removal, I may use 4200 as the Interlux Bedding Compound does not appear to be listed as a product available here in OZ.

I can get the centreboard out of the C/B case and out of the cabin without removing the C/B case. My cabin top was built 3" higher than the plans and this gives about 2" clearance to allow the removal of the centreboard. Looks like the builder planned ahead!

Dave

The first experience I have had of your winters was one night in Dorval airport when I stopped there on the way from Wichita to home here via the North Alantic, Europe and SE Asia while bringing a new Cessna Citation home. I wondered what all the 6 foot high mounds of white stuff in the carpark was. Soon found out when I tried to walk through it.

[ 01-24-2003, 02:57 AM: Message edited by: JimJ ]

[JormaS]

Jim,

Maybe you could put a bead of polyurethane sealant on the keel and let it cure, then bolt the centerboard case in place. You would then actually have a gasket attached to the keel and the case would be easy to remove when needed.

The sealant should be rather soft/elastic so that enough compression is achieved via the bolts. Too thick a "gasket" could result in a wobbly construction. Maybe two or more beads would be better than one.

I have´nt tried this but it crossed my mind as a possible solution.

Jorma

[reddog]

Jim;
I guess it really boils down to how often will you be removing the case?I would go for one of the adhesive sealants or bedding compound already mentioned.Yes 5200 is tenacious but it cuts easily with a heated knife or wire.More of a pain than anything and since you probably won't be taking the case out more than once more,hopefully,would go with that.
Earl

[ 01-26-2003, 05:33 PM: Message edited by: reddog ]

[JimJ]

Thanks for the suggestions.

What I plan to do after reading the above replies

Use 4200 as it is not a strong an adhesive as 5200. There are enough bolts to give the assembly structual strength.

Put a layer on and sit the C/B case on top if the 4200 but held up slightly with washers under the edges until the 4200 cures.

Take the washers out and and tighten the C/B case bolts.

Whatever I do will be better than what was remaining of the previous sealant and I had no leaks then.

[reddog]

Jim;
Good luck and let us know how it works out.
earl

[JimJ]

I was thinking of a thin gasket of neoprene.

Been reading some old posts and I was supposed to let y'all know how I sealed the joint between the C/B case and keelson
I made a one piece gasket out of 2mm thick neoprene with no other sealant. It has been working a treat with no indication of water leak.
Sorry for the delay.

[Thorne]

Thanks for the feedback -- this makes similar decisions much easier for the rest of us.

BTW, I just resealed the edges of my CB case with 5200. I had used Vulkem116 (very similar to 4200), but it had detached from some of the edges of the CB case and nearby cleats. Rather than use epoxy I went for 5200, and understand that if I pull the CB case it will take some of the softer wood along with it...

[wizbang 13]

How many times have you taken it out in 7 years?

[JimJ]

How many times have you taken it out in 7 years?

I have only had it out once. But you never know.

[David G]

Another brand of the linseed oil based bedding compounds is "Dolphinite". I'd be inclined to stick with something a bit stickier... but I can see your reasoning.

[paul oman]

rubberized epoxy paste.....