Keel Bedding

[landrover]

Hi All

Doing a rebuild of a cvx 16, and am about to lay in the keel. Bought marine high strength filler, but max thickness per app is 3/8ths. I fear my keel might have some larger gaps between it and the hull,so i'm wondering what alternative i have? Does the peanut butter recipe work for this strructural need?Or can i adjust it to do so. I am reluctant to use the 3m fillers because the window is small for working, and my area is quite large and it is quite expensive .I would feel better knowing i could build a 1/2 inch bed that i could "squish" the keel into eliminating gaps.Also, how many layes of glass are required after she is set in to keep it in place and locked down.
Thx all
Landrover

 

[notsunkyet]

Re: Keel Bedding

ok uhhhhhhh are you bilding a glastron? if you redoing the keel then there is no room to be cheap or shotty work it has to be done right! im no expert but it has to be right.... Id get in touch with OOPS he added a whole nother boat to one! so he would know what to use but i would only use heavy mat or roven and at least 3-5 layers

 

[landrover]

Re: Keel Bedding

Anyone else?

The factory bedding was over an inch high in places so i'm not sure if my gaps could be considered cheap or shoddy. It is a laminated keel, 3 layers of 3/4 ply for a 2.25 inch width, so it is quite stout,which is cause for a large amount of bedding, thereby reducing the window for working per sqaure inch.
Much obliged

 

[jonesg]

Re: Keel Bedding

Just use PL Premium construction adhesive in the cartridges, works out great and cheaper than marine supplies. Did both my stringers in a 20 footer.
Lay a thick bead and gently press the stringer in to the correct height.
It has a 30 minute reposition window, plenty of time to get it right.

Bedding is only to establish spacing between the stringer and hull, strength comes from the glass on each side. Some guys use foam to space the stringer.

I also found it a LOT easier to pre-glass the stringers but mine are 20 inches in height, that was a LOT of side area to glass, if yours are low profile then its easier to just glass in situ.

 

[landrover]

Re: Keel Bedding

Wow,construction adhesive?
That's the first i've heard of anyone using or recomending it as bedding.You wouldn't happen to have a link to an article with more info,do you? Also after time would it not be overly brittle? The marine filler would be stronger andmore stable,would it not? I just seem to think of the globs of pl on the floor after a job,and it doesn't seem like the strongest thing for the keel area.Does it actually establish height as well?Because it seems so soft that she would sink right to the bottom,but that may be your point,for the foam too.My keel will sit right on the bottom and the squeeze out would ensure me of no gap,right?Then glass the hell out of it (i've also got some scrap carbon fibre) to keep it from tipping over? 3 layers plus carbon fibre "stiched" every few inches should be about right? Is there a max thickness for the PL? Does the PL readily accept fibre and resin,or is there prep involved prior to glassing?
Many Thanks

 

[landrover]

Re: Keel Bedding

Hi,

Any thoughts on this anyone?

 

[erikgreen]

Re: Keel Bedding

Bedding can be anything... its main purpose is to ensure that plywood bulkheads and stringers don't press hard against the fiberglass hull and create a spot where cracks will form.

You can even skip the "bedding" entirely and space the plywood off the hull with plastic spacers or foam, then hold it in place with a jig or similar and glass. What you're trying to do with the bedding is to get the fiberglass around the plywood to carry the force from the hull to the stringer. As long as you accomplish that, the bedding is irrelevant. Properly installed the bedding won't actually do any job at all once the fiberglass hardens.

If you want super strength, bed the stringers in resin putty. Since the resin putty flexes at about the same rate as fiberglass and since it provides a continuous even connection between the stringer and the hull, it works like having a third fiberglass connection(in addition to the tabs on both sides).. overkill for most people though.

Unfortunately the PL adhesive is more flexible than the fiberglass you put around it, so it adds very little strength to the stringers.. it basically lets the stringers move just a little, until the fiberglass stops them. So it can be filed in the same group of methods as air, plastic spacers and foam... bedding that doesn't add strength.

Erik