Floor Boards: Screws vs Epoxy

[bassman1956]

Okay, I'm pretty familiar with the concept and ways to bed all screws etc in epoxy for "forever" applications. But what do I do about things like floorboard screws, where I want to have holes sealed and bedded in epoxy to prevent water damage, yet want the screw to be removable for service?

Through the floorboard, this doesn't look like much of an issue. Just don't bury the screw head in epoxy, right? But what do I do about the threaded end into the frame? Put a dab in the screw threads hole, then drive home the screw? Will it still be removable?

[PAR]

Use a "release" agent on the screws before inserting them into the wet goo. You can also use machine screws or bolts, which have better holding power amazingly enough, again with wax or other release agent applied to the threads.

Log onto Epoxy by the Leading Epoxy Manufacturer | WEST SYSTEM Epoxy and look up bonding fasteners. Your description sounds like a few short cuts are being taken.

Even if the fastener is not coated with a release agent, they're fairly easy to remove with a soldering gun. I use a slightly different approach, because the soldering iron thing takes too long for me. I place a screw driver in the slot on the fastener then heat the driver shaft with a MAPP gas torch (the driver is pre-heated too). This will permit you to push right through epoxy covered heads and burn out any filled slots too (if necessary).

[David_Old_Jersey]

Originally Posted by bassman1956

Okay, I'm pretty familiar with the concept and ways to bed all screws etc in epoxy for "forever" applications. But what do I do about things like floorboard screws, where I want to have holes sealed and bedded in epoxy to prevent water damage, yet want the screw to be removable for service?

Through the floorboard, this doesn't look like much of an issue. Just don't bury the screw head in epoxy, right? But what do I do about the threaded end into the frame? Put a dab in the screw threads hole, then drive home the screw? Will it still be removable?

Not entirely sure I understand what you are describing - but that may be me more than you

I am thinking this is a non-structural job, screwed down because floorboards rarely removed for access.

What I have done is drill out the threaded end in the frame oversize and also then countersink. Then I fill with thickened epoxy (whatever filler I have handy - still pourable though) to create a plug - you want the hole a good oversize for both ease of pouring (too small and air gets trapped) and to give leeway when you re-drill. If you pick the right sized drill the screw will tap it's own thread. A bit of filler builds in a bit more give than straight epoxy.

In an ideal world I would want access to both sides so I could countersink both ends - it's how I would do the floorboards themselves. But if inside I would (and have) sometimes simply use paint and also stop the water coming in

The one sided approach probably won't allow the boat to hang from the floorboards - but should be good enough for most circumstances that require the floorboards staying fixed - including being upside down . Try first on a piece of scrap wood, then place it in a vice. If you can pull the screw out (or detach the epoxy plug) then you have biceps like Popeye . and are on PCP

Of course it all relies on filling good wood - if it's rotten then the epoxy plug will be fine, just won't neccessarily stay attached

[S&S]

Epoxy the hole and bed the screw in Lifecaulk.
We put in the PYI bayonet fasteners in our floorboards- much better solution than screws.

[PAR]

I use a torpedo cabinet latch (if I have the room), which is similar to what you're doing S&S.

Bonded fasteners is an easy and commonly employed method and doesn't require re-drilling cured epoxy. Typical clearance hole diameter is 130% to 150% of the screw shank. Anything more then this is a waste of epoxy. By the way, if your epoxy is cured enough to permit drilling, a screw's threads will not cut a clean (nor reliable) set of threads.

It's only a floorboard so strength isn't a real issue, but access can be. Blind nuts are a good choice if it's new construction (or if you have access to the back side) and you can incorporate fore thought and planning. I use bonded fasteners if I want a high strength, solid fastener attachment with limited access potential. I use torpedo latches if a fair bit of use is expected.

[svHyLyte]

Another alternative, depending upon the construction of ones floors (the beams that support the sole decking) is to drill and tap the floors and then insert heli-coils with a bit of epoxy on the outside of the coil to transfer shear loading into the floor. With that, a conventional screw can then be used to fasten the deck in place. I don't know about others but we have a fair amount of weight under the sole--including 50' of spare 3/8" chain to add to the anchor rode when needed--and it would be vary inconvenient to have that gear go adrift in a knock-down, eh?

Heli-coils (Heli-Coil Inserts Free Running and Screw Lock | Emhart.com ) are far less costly than PYI Bayonet locks but perform the same essential function.

FWIW...

[S&S]

Originally Posted by svHyLyte

Another alternative, depending upon the construction of ones floors (the beams that support the sole decking) is to drill and tap the floors and then insert heli-coils with a bit of epoxy on the outside of the coil to transfer shear loading into the floor. With that, a conventional screw can then be used to fasten the deck in place. I don't know about others but we have a fair amount of weight under the sole--including 50' of spare 3/8" chain to add to the anchor rode when needed--and it would be vary inconvenient to have that gear go adrift in a knock-down, eh?

Heli-coils (Heli-Coil Inserts Free Running and Screw Lock | Emhart.com ) are far less costly than PYI Bayonet locks but perform the same essential function.

FWIW...

That's an idea but it still doesn't provide fast access to the bilge. Push n' twist is a lot quicker. ( especially when you just HAVE to find out where that water is coming from )

[svHyLyte]

Originally Posted by S&S

That's an idea but it still doesn't provide fast access to the bilge. Push n' twist is a lot quicker. ( especially when you just HAVE to find out where that water is coming from )

I agree with you on that. But $14.95 USD each for a single fastener...ouch!

[Minggat]

[QUOTE=bassman1956;480892]Okay, But what do I do about things like floorboard screws, where I want to have holes sealed and bedded in epoxy to prevent water damage,

QUOTE]

How much water are you expecting to get on your floorboards?

[bassman1956]

[QUOTE=Minggat;481607]

Originally Posted by bassman1956

Okay, But what do I do about things like floorboard screws, where I want to have holes sealed and bedded in epoxy to prevent water damage,

QUOTE]

How much water are you expecting to get on your floorboards?

How much does it take to do damage?

[Minggat]

[QUOTE=bassman1956;481756]

Originally Posted by Minggat

How much does it take to do damage?

Sorry for my less than intelligent reply. I hate when people do that to my post.

I'm just picturing as much effort going into this as you would give something with exterior exposure. If I were to get enough water in for me be concerned, I'd be a lot more worried about where the water is coming from. This is coming from a guy with a vinly teak and holly sole.

Bottom line. Feel free to disregard anything I say.

[bassman1956]

This boat will see most of it's time out of the water in dry storage, on the trailer, tarped or covered. It will see weekends or weeks of action at a time, maybe 6 or 10 times a year.