On Tue, 25 Jul 2017 21:46:00 +0200, Emanuel Berg <
moa...@zoho.com>
wrote:
>Jeff Liebermann wrote:
>
>> The threads have sharp edges and do a good
>> job of shaving the edges of the hole until
>> the screw comes loose. Replacing such a wood
>> screw with a larger size screw will just cut
>> a bigger hole in the deck.
>
>Good points.
Nope. The screw only has one point.
>> As long as things are moving, epoxy won't
>> work. It's not flexible and will crack.
>> Rubber gaskets might help if the deck is
>> flexing, but if the damage is caused by
>> someone walking on the deck plate, then
>> rubber will simply increase the amount
>> of movement.
>If we assume no one will walk on the plates, do
>they still move enough so that epoxy won't
>work?
I can't answer that. The problem is that you haven't disclosed the
type of wood decking, number of layers, thickness, condition of the
wood, surface finish, preservatives used, type of deck plate, type of
fasteners, size of fasteners, number of fasteners, etc. In other
words, what you have to work with. I can't tell from here. If the
wood is soft, soaked with water, and the fasteners have shallow
threads, any movement is going to turn the soft wood in the hole to
sawdust or mush. The problem is that there is no way that the deck is
going to be totally rigid. Wooden boats creak and groan, which are
all signs of fasteners sliding in and out of holes in the wood. It's
the same noises you hear walking on a badly installed oak floor.
Epoxy is a different nightmare. The problem is that it's great in
compression, fairly good in tension, and miserable in torsion
(bending). In other words, it's easy to break if you bend an epoxy
glued joint, which is what might happen if someone steps on the joint.
For the major structures and laminated parts on a wooden boat, epoxy
is great because those are mostly in compression. It's also great for
gluing in wooden hole plugs. However if you use epoxy for repairs,
and the joint moves as in a wood screw holding down a moving deck
plate, it can break.
Article on the different wooden boat fixit glues:
<
http://www.tonygrove.com/articles/boat-repair-adhesives.php>
>The reason I put hopes in epoxy is
>because doing all this the dowel or "rotate"
>way is a lot of work. What especially makes me
>discouraged is all the things, already in their
>right places, that has to be removed first.
>But of course, if it needs to be done it is not
>something that is impossible to do.
Well, if you like epoxy so much, perhaps you should sell the wooden
boat and get a fiberglass and epoxy replacement? I can't tell how
much time and work would be saved by using epoxy instead of wooden
dowels and plugs.
>> Think about using FH bolts, washers, and
>> captive nuts to secure the deck plate, or
>> just fix whatever is causing the flexing or
>> fastener movement.
>FH bolts, does that require drilling down to
>the other side, i.e. thru the ceiling, to
>release the wings?
I'm not suggesting drywall expanding fasteners. I'm guessing that you
might have access to the underside of the deck through the cabin or
bilge. If so, you can install a fastener that does not require
screwing into the wood, such as a nut, bolt, and washer sandwich.
Maybe a nut plate, captive nut, or pronged tee nut can be used.
<
https://www.google.com/search?q=pronged+tee+nut+stainless&tbm=isch>
Perhaps it might be more useful to ask in a wooden boat forum?
<
http://forum.woodenboat.com>
<
https://www.google.com/search?q=wooden+boat+forum>
Obligatory mention of bicycling:
Does a wooden boat always have a wood frame bicycle for shore travel?