Thru-hull mounting revisited
 

Some time ago, I asked how to secure a thru-hull with a flat nut to a
curved hull. Lots, of good advice..thanks to all who responded.

I tried the solution I favored, but had never tried, after much self-doubt.

In a nut-shell: I cut the top off a tupperware container..one with a stout
rounded lip. The height after cutting is about 3/8".

I duct taped it over the existing hole, top and bottom, being careful to
not distort the sides.

I then mixed epoxy with high-strength filler (West 404), until I had stiff
peanut butter consistancy, then dabbed enough around the inside of the
"mold" to fix it in position.

When that had set, I filled the rest of the mold with epoxy, and leveled
it using a 8" wide plastic "scraper". This made the top of the epoxy pad
very level...or flat may be a better word. A 2" hole saw finished the job.

Now I have a 6" thru-hull pad which is flat for the nut, and still conforms
perfectly to the hull shape.

You may ask, "How did he keep the epoxy from dripping through the
existing hole?"
Answer: I cut a 4" (or so) square of material from a freezer bag, draped
that over the large end of a tapered wood plug, and wedged it into the
hole from the outside...but not so far as to go completly through the hull...
I wanted epoxy to fill about 1/8" of the hole.

Once done, it was apparent that the doing was easier than the telling.
Norm B

On Thu, 23 Jun 2005 10:23:36 -0700, engsol
wrote:


Once done, it was apparent that the doing was easier than the telling.
Norm B

Good tip and solution, and stuff like this gets mentally filed.

Thanks!

R.

"engsol" wrote in message
...
Some time ago, I asked how to secure a thru-hull with a flat nut to a
curved hull. Lots, of good advice..thanks to all who responded.

I tried the solution I favored, but had never tried, after much
self-doubt.

In a nut-shell: I cut the top off a tupperware container..one with a stout
rounded lip. The height after cutting is about 3/8".

I duct taped it over the existing hole, top and bottom, being careful to
not distort the sides.

I then mixed epoxy with high-strength filler (West 404), until I had stiff
peanut butter consistancy, then dabbed enough around the inside of the
"mold" to fix it in position.

When that had set, I filled the rest of the mold with epoxy, and leveled
it using a 8" wide plastic "scraper". This made the top of the epoxy pad
very level...or flat may be a better word. A 2" hole saw finished the
job.

Now I have a 6" thru-hull pad which is flat for the nut, and still
conforms
perfectly to the hull shape.

You may ask, "How did he keep the epoxy from dripping through the
existing hole?"
Answer: I cut a 4" (or so) square of material from a freezer bag, draped
that over the large end of a tapered wood plug, and wedged it into the
hole from the outside...but not so far as to go completly through the
hull...
I wanted epoxy to fill about 1/8" of the hole.

Once done, it was apparent that the doing was easier than the telling.
Norm B

One thing I do that really helps is to take pictures of before, during, and
after the procedure. This gives you a record of what was done and how it was
done. Sometimes it's easy to forget something and hard to explain it to
someone else. I did this on my boat, the house...

--
"j" ganz @@
www.sailnow.com

engsol wrote:
Some time ago, I asked how to secure a thru-hull with a flat nut to a
curved hull. Lots, of good advice..thanks to all who responded.

I tried the solution I favored, but had never tried, after much self-doubt.

In a nut-shell: I cut the top off a tupperware container..one with a stout
rounded lip. The height after cutting is about 3/8".

I duct taped it over the existing hole, top and bottom, being careful to
not distort the sides.

I then mixed epoxy with high-strength filler (West 404), until I had stiff
peanut butter consistancy, then dabbed enough around the inside of the
"mold" to fix it in position.

When that had set, I filled the rest of the mold with epoxy, and leveled
it using a 8" wide plastic "scraper". This made the top of the epoxy pad
very level...or flat may be a better word. A 2" hole saw finished the job.

Now I have a 6" thru-hull pad which is flat for the nut, and still conforms
perfectly to the hull shape.

You may ask, "How did he keep the epoxy from dripping through the
existing hole?"
Answer: I cut a 4" (or so) square of material from a freezer bag, draped
that over the large end of a tapered wood plug, and wedged it into the
hole from the outside...but not so far as to go completly through the hull...
I wanted epoxy to fill about 1/8" of the hole.

Once done, it was apparent that the doing was easier than the telling.
Norm B

engsol wrote:
...tupperware container... epoxy...
Now I have a 6" thru-hull pad which is flat for the nut, and still conforms
perfectly to the hull shape.

Sounds like a great job. The only refiniement I'd think about is to have
put some fiberglass cloth into it, as well as #404 filler. I've had some
bad luck with epoxy melting the plastic, trying similar fixes, but am
not sure if it was due to chemistry or temp. A bit more clean-up, but no
difference in the final result.

So, when are you going to come over and do that job on my boat?
;)

Fresh BReezes- Doug King

On Mon, 27 Jun 2005 11:35:35 -0400, DSK wrote:

engsol wrote:
...tupperware container... epoxy...
Now I have a 6" thru-hull pad which is flat for the nut, and still conforms
perfectly to the hull shape.

Sounds like a great job. The only refiniement I'd think about is to have
put some fiberglass cloth into it, as well as #404 filler. I've had some
bad luck with epoxy melting the plastic, trying similar fixes, but am
not sure if it was due to chemistry or temp. A bit more clean-up, but no
difference in the final result.

So, when are you going to come over and do that job on my boat?
;)

Fresh BReezes- Doug King

Hi Doug,
Odd you should mention #404 filler...that's exactly what I used...:)
One step I left out...I did the 'filling' in two shots...I was worried about
heat when the epoxy went off, and it did get warm, but not much.
I thought about using cloth, but figured since the load is compression,
it wasn't needed. If I later post a plea for advice in repairing a really
big hole in the hull, I'll be the first to admit I was wrong.
As to giving you a hand...where are you located?
Norm B

engsol wrote:
Hi Doug,
Odd you should mention #404 filler...that's exactly what I used...:)

I know... you mentioned it in your earlier post! But I was going to
mention that 404 is a high-hardness filler, not necessarily the same
thing as strength.

Putting a layer of cloth in would make the pad stronger, and more
cohesive with the hull, without reducing it's ability to take a lot of
compression from the bolts. Not necessary, but desirable perhaps...
unless you need to reshape the pad in the future, which is the way
things like this usually work out for me...


As to giving you a hand...where are you located?

North Carolina... right now I'm fiberglassing up a freezer chest...
starting work on the lids this afternoon, I hope. Another project for
the (hopefully) near future is a carbon fiber dinghy. I was kidding
about working on my boat, but if you're in the neighborhood you'd be
very welcome to drop by.

Fresh Breezes- Doug King