I'm doing some research about replacing my bulkheads on my Cal 27 and I'm looking for some advice regarding the foam strip between the bulkhead and hull. What kind have any of you used or recommend?
Foam between bulkhead and hull
- Thread starter saltysailor
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I use Klegecel in a 'trapazoidial' form for bulkhead to hull connections. If you make the connection 'solid' you risk creating 'hard spots' on the hull exterior; the 'trapazoidial' shape 'turns' the applied stress created by the applied 'fillets' to act somewhat parallel to the hull surface instead of perpendicular (hence eventual 'hard spots' showing on the topsides).
Of course if this is a free-floating 'flanged' connection, common to Pearsons, etc., then anything 'soft' you put in there will reduce the amount of 'bulkhead squeek' when the hull is 'twisting'.
Of course if this is a free-floating 'flanged' connection, common to Pearsons, etc., then anything 'soft' you put in there will reduce the amount of 'bulkhead squeek' when the hull is 'twisting'.
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Joe, the problem is that 'polyester' never 'fully cures' and adverse pressure (from bulkheads, etc.) causes the hull, etc. to 'creep' at the 'joint' ... and thats one reason that old FRG hulls eventually 'get the bumps' on their outer surfaces, especially if the hull undergoes large (daily, etc.) swings in 'temperature', etc.
How big of a deal is this? Is this something that takes decades to develop? Thin hulls only?
Just curious
Just curious
Any foam will do as long as it is closed cell so it doesn't absorb the resin when you glass the bulkhead in. Trapezoidal shape saves using epoxy to create fillets.
You don't have to use foam actually. Morris uses spacers to hold the bulkhead off the hull. After one side is taped the spacers are removed and the other side taped. The aim is to let the taping take the entire load without any hard spots.
You don't have to use foam actually. Morris uses spacers to hold the bulkhead off the hull. After one side is taped the spacers are removed and the other side taped. The aim is to let the taping take the entire load without any hard spots.
Thanks guys. It seems like closed cell pipe insulation foam would be both easy to cut, shape and cheap. The Klegecell looks to be a little bit hard to find and very expensive. Maybe I'm wrong?
Oh and thanks Rich H for the photo/diagram. The trapazoidal shape makes a lot of sense regarding using less epoxy for the filet.
CB - Thin hulls especially from the 70s and 80s and white hulls (with insufficient matting layers under the gelcoat) that are painted 'dark' are especially prone to 'hard spots' developing at the bulkhead/hull connections. Its a big deal if you're 'fastidious' about your boat and is cause for 'negotiations' when you go to sell one with 'the bumps' showing.
Hmmm. . .3 of my 4 bulkheads have space. . .one of the two the PO replaced (stbd. @ mast, smaller of the two) was puttied tight to the hull. Been 8 years like that and no gelcoat crazing, but is this something that would be worth say, cutting a space out along the hull and re-tabbing one side at some point?
LoL, I've been hearing that a lot from family and freinds recently with my ongoing "boat projects"
I'll add that to a slowly growing list of things that I'm trying to leave alone until they actually need to be addressed :dance:
Thanks!
I'll add that to a slowly growing list of things that I'm trying to leave alone until they actually need to be addressed :dance:
Thanks!
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