Bonding stringers to hull?

[CCrew]

Ok, I have researched until I'm blind, and there seemm to be two trains of thought..<br /><br />1: That you should epoxy bed the stringers to the hull to attach.. Then glass in place<br /><br />2: That you shouldn't bond, as flex needs to occur and two different materials will invariably flex at different rates..and crack therefore they should be placed and then fillet and glass.. basically a stitch and glue.<br /><br />There also seems to be diversion as to whether to use woven, mat and cloth, bi-axial tape, etc. <br /><br />All seem to refer to the fact that it's the glass encapsulation that creates the strength, and not the actual stringer itself. #2 appears to be the way Project Bilgeliner was built, not that that means anything. <br /><br />Opinions, thoughts.. assorted "you're crazy's" appreciated. <br /><br />Thanks!<br />Roger

 

[crab bait]

Re: Bonding stringers to hull?

fillet an gluing is in essinces the same thing.. <br /><br />glueing = stra8 epoxy or with fillers..<br /><br />fillets = making putty with epoxy an fillers..<br /><br />either way it's still adherin' them down..<br /><br />'glass 'em in'...... you must make fillets,,anyway.... glass don't stick to sharp right angles.. hence the fillets...<br /><br />if'n your gonna use glass... go only with biaxail.. anythin' else is a waste... <br /><br />the wood is the strenght.. the glass is redundant.. an keeps wood from checkin'..<br /><br />i'd go glue,, than make fillets,, than biaxial,, but only the bottom hull juncture.. <br /><br />before you lay the floor,,, spread made-up epoxy putty ( peanut butter ) on top of stringers than pour on some liquid 'fresh' epoxy ( honey ) on the putty ( just a line )... then lay an screw floor down... <br /><br />ain't nothin' like 'peanut butter an honey' for a good job... they sure go together..

 

[Columbia]

Re: Bonding stringers to hull?

Bonding rigid wood to flexible fiberglass can result in the glass or the bond cracking under stress. Some boat builders bond directly to hull with resin putty, then glass. Some lay in a strip of good quality closed cell foam like Airex tapered out from the wood. This provides a cushion to prevent a 'hard spot' in the hull around which the rest of the hull flexes. A lot depends on how the boat was originally designed and built. I'd say if they bonded directly to the hull, that's what I'd do. One drawback that I can see to bonding stringers with an epoxy fillet only is it provides no anti-moisture/rot protection should water get under the fillet in some spot. If the stringer was epoxy coated on the bottom it would help. I confess I might not bond the floor to the stringers with epoxy because then you can't ever easily remove it to deal with problems underneath. I don't know how most powerboats are built these days but I like access to the nether regions of boats I own and would use caulk and fasteners unless I had knowledge to the contrary. Most of my work has been on sail boats over the past 35 years and while most stuff is the same, lots ain't, I'm sure.

 

[crab bait]

Re: Bonding stringers to hull?

the bad part about NOT gluin' down the floor in a power boat for one... it's gotta be one big tied together unit.. not somethin'that is ,, an another part floatin' or less connected.. you'll have problems for sure..<br /><br />another bad thing about NO glue floor an just rely on screws is that water/moisture/rot will seep down around the screws to rot the floorin' an the stringers ,straightaway... an let's not fool ourselves, fellas... chaulks don't really work...water will get in an do it's deed <br /><br />i know ,,, when ya do a job like this... ya want to have it all... to be able to remove the floor for inspection an to replace if nessassary... <br /><br />but don't go there... if ya don't epoxy putty the floor down an run screws thru the putty into the stringers ( putty seals the screw shank an penetratin' hole ) an countersink the heads an epoxy putty them over.. <br />you'll be takin' up the floor in short years to do everthin' again... a second time... <br /><br /> do it rite the first time ,,, seal it up good with epoxy an epoxy products an it'll be good as a family hierloom...

 

[Bondo]

Re: Bonding stringers to hull?

crab bait's Got It.......<br />You're Glueing together a bunch of boxes.......<br />So, Use Alot of Glue.......<br />I'm a Believer in Option #1....