Tapered thread thru-hulls ?
 

Does anyone know of a source for BRONZE tapered thread [pipe thread]
thru-hulls?

The thru-hulls sold by Worst Marine and others are all "straight
thread" with straight thread tightening nuts. The sea-cocks that go
on these thru-hulls are also straigh threaded, but are designed to be
bolted [ usually 3 bolts ] through the hull also. It would seem that
for a fiberglass hull the less holes the better.

So many people put a tapered thread ball valve [seems like all ball
valves are tapered threaded] on to the straight thread thru-hull. Not
a good idea.

T. Sanders
S/V Cimba

Tapered thread thru-hulls ?
 

Clean the inside of the hull, in a non-cored area, where you want to place
the thru hull fitting. I use Dupont Y-3919S Prep-Sol solvent and 16 to 25
grit sanding disks on a right-angle sander. Cut a disk of 3/4" to 1" thick
teak about 4 to 6 inches bigger in diameter than the base of your seacock.
Round the top edge with a router. Stick it to the cleaned area of the hull
with thickened epoxy and use the excess epoxy to shape a rounded taper where
the teak meets the hull. Tongue depressors work great for this. The area of
the cleaned hull should be at least 8 inches in diameter larger than the
teak disk.

After the epoxy has set cover the teak disk and out to the edge of the
cleaned hull area with two or more layers of fiberglass and straight epoxy.
Smooth it down over the teak, over the rounded edges, and on to the hull.
Work out all air bubbles. After it's cured, clean it with water and paint it
your favorite color. I use three coats of Pettit Easypoxy deck paint over
two coats of Pettit white undercoater. Don't forget the primer coats, I've
seen the top coats not cure when placed over non-primered epoxy.

When all is dry, drill through the middle of the teak disk and the hull
using the correct hole saw to fit your non-tapered thread thru-hull. Check
the length of the thru-hull and trim it if it hits the works on the inside
of the seacock. Coat the inside of the hole with 3M 4200 Marine Adhesive
Sealant and put a bead on the thru-hull and the seacock. Fit the thru-hull
in place and screw the seacock to it. For final fitting hold the seacock in
position and have someone tighten the thru-hull from the outside. The ridges
inside the thru-hull are there just for this. You can even get a tool that
fits inside several different sizes of thru-hulls and lets you do this
easily. The excess 4200 can be cleaned off with paint thinner.

Use a 1/8" pilot bit to start screw holes for the seacock mounting holes.
Use 3/4" or 1" long #10 stainless steel pan head sheet metal screws and
washers to fasten the seacock to the teak disk. Ace Hardware has a good
supply of these. Just screw into the teak, not the hull. A little MaryKate
Tek Gel on the hardware will help prevent corrosion.

A lot of work, but worth it.

Rusty O

Tapered thread thru-hulls ?
 

Clean the inside of the hull, in a non-cored area, where you want to place
the thru hull fitting. I use Dupont Y-3919S Prep-Sol solvent and 16 to 25
grit sanding disks on a right-angle sander. Cut a disk of 3/4" to 1" thick
teak about 4 to 6 inches bigger in diameter than the base of your seacock.
Round the top edge with a router. Stick it to the cleaned area of the hull
with thickened epoxy and use the excess epoxy to shape a rounded taper where
the teak meets the hull. Tongue depressors work great for this. The area of
the cleaned hull should be at least 8 inches in diameter larger than the
teak disk.

After the epoxy has set cover the teak disk and out to the edge of the
cleaned hull area with two or more layers of fiberglass and straight epoxy.
Smooth it down over the teak, over the rounded edges, and on to the hull.
Work out all air bubbles. After it's cured, clean it with water and paint it
your favorite color. I use three coats of Pettit Easypoxy deck paint over
two coats of Pettit white undercoater. Don't forget the primer coats, I've
seen the top coats not cure when placed over non-primered epoxy.

When all is dry, drill through the middle of the teak disk and the hull
using the correct hole saw to fit your non-tapered thread thru-hull. Check
the length of the thru-hull and trim it if it hits the works on the inside
of the seacock. Coat the inside of the hole with 3M 4200 Marine Adhesive
Sealant and put a bead on the thru-hull and the seacock. Fit the thru-hull
in place and screw the seacock to it. For final fitting hold the seacock in
position and have someone tighten the thru-hull from the outside. The ridges
inside the thru-hull are there just for this. You can even get a tool that
fits inside several different sizes of thru-hulls and lets you do this
easily. The excess 4200 can be cleaned off with paint thinner.

Use a 1/8" pilot bit to start screw holes for the seacock mounting holes.
Use 3/4" or 1" long #10 stainless steel pan head sheet metal screws and
washers to fasten the seacock to the teak disk. Ace Hardware has a good
supply of these. Just screw into the teak, not the hull. A little MaryKate
Tek Gel on the hardware will help prevent corrosion.

A lot of work, but worth it.

Rusty O

Tapered thread thru-hulls ?
 

Great reply and worth saving :)
Bruce
"Rusty O" wrote in message
ink.net...
Clean the inside of the hull, in a non-cored area, where you want to place
the thru hull fitting. I use Dupont Y-3919S Prep-Sol solvent and 16 to 25
grit sanding disks on a right-angle sander. Cut a disk of 3/4" to 1" thick
teak about 4 to 6 inches bigger in diameter than the base of your seacock.
Round the top edge with a router. Stick it to the cleaned area of the hull
with thickened epoxy and use the excess epoxy to shape a rounded taper
where
the teak meets the hull. Tongue depressors work great for this. The area
of
the cleaned hull should be at least 8 inches in diameter larger than the
teak disk.

After the epoxy has set cover the teak disk and out to the edge of the
cleaned hull area with two or more layers of fiberglass and straight
epoxy.
Smooth it down over the teak, over the rounded edges, and on to the hull.
Work out all air bubbles. After it's cured, clean it with water and paint
it
your favorite color. I use three coats of Pettit Easypoxy deck paint over
two coats of Pettit white undercoater. Don't forget the primer coats, I've
seen the top coats not cure when placed over non-primered epoxy.

When all is dry, drill through the middle of the teak disk and the hull
using the correct hole saw to fit your non-tapered thread thru-hull. Check
the length of the thru-hull and trim it if it hits the works on the inside
of the seacock. Coat the inside of the hole with 3M 4200 Marine Adhesive
Sealant and put a bead on the thru-hull and the seacock. Fit the thru-hull
in place and screw the seacock to it. For final fitting hold the seacock
in
position and have someone tighten the thru-hull from the outside. The
ridges
inside the thru-hull are there just for this. You can even get a tool that
fits inside several different sizes of thru-hulls and lets you do this
easily. The excess 4200 can be cleaned off with paint thinner.

Use a 1/8" pilot bit to start screw holes for the seacock mounting holes.
Use 3/4" or 1" long #10 stainless steel pan head sheet metal screws and
washers to fasten the seacock to the teak disk. Ace Hardware has a good
supply of these. Just screw into the teak, not the hull. A little MaryKate
Tek Gel on the hardware will help prevent corrosion.

A lot of work, but worth it.

Rusty O

Tapered thread thru-hulls ?
 

Great reply and worth saving :)
Bruce
"Rusty O" wrote in message
ink.net...
Clean the inside of the hull, in a non-cored area, where you want to place
the thru hull fitting. I use Dupont Y-3919S Prep-Sol solvent and 16 to 25
grit sanding disks on a right-angle sander. Cut a disk of 3/4" to 1" thick
teak about 4 to 6 inches bigger in diameter than the base of your seacock.
Round the top edge with a router. Stick it to the cleaned area of the hull
with thickened epoxy and use the excess epoxy to shape a rounded taper
where
the teak meets the hull. Tongue depressors work great for this. The area
of
the cleaned hull should be at least 8 inches in diameter larger than the
teak disk.

After the epoxy has set cover the teak disk and out to the edge of the
cleaned hull area with two or more layers of fiberglass and straight
epoxy.
Smooth it down over the teak, over the rounded edges, and on to the hull.
Work out all air bubbles. After it's cured, clean it with water and paint
it
your favorite color. I use three coats of Pettit Easypoxy deck paint over
two coats of Pettit white undercoater. Don't forget the primer coats, I've
seen the top coats not cure when placed over non-primered epoxy.

When all is dry, drill through the middle of the teak disk and the hull
using the correct hole saw to fit your non-tapered thread thru-hull. Check
the length of the thru-hull and trim it if it hits the works on the inside
of the seacock. Coat the inside of the hole with 3M 4200 Marine Adhesive
Sealant and put a bead on the thru-hull and the seacock. Fit the thru-hull
in place and screw the seacock to it. For final fitting hold the seacock
in
position and have someone tighten the thru-hull from the outside. The
ridges
inside the thru-hull are there just for this. You can even get a tool that
fits inside several different sizes of thru-hulls and lets you do this
easily. The excess 4200 can be cleaned off with paint thinner.

Use a 1/8" pilot bit to start screw holes for the seacock mounting holes.
Use 3/4" or 1" long #10 stainless steel pan head sheet metal screws and
washers to fasten the seacock to the teak disk. Ace Hardware has a good
supply of these. Just screw into the teak, not the hull. A little MaryKate
Tek Gel on the hardware will help prevent corrosion.

A lot of work, but worth it.

Rusty O

Tapered thread thru-hulls ?
 

Tapered thread thru-hulls ?
 

Tapered thread thru-hulls ?
 

Not sure I understand your reply,,, do you mean to say that tapered
[pipe] threads wouldn't "snug down" like straight threads? Seems like
when I do plumbing around the house that that's the case.

Maybe I should have asked the question of whether anyone makes a
straight threaded ball valve.

Trent
S/V Cimba

(John) wrote in message . com...
(Trent D. Sanders) wrote in message . com...
Does anyone know of a source for BRONZE tapered thread [pipe thread]
thru-hulls?

The thru-hulls sold by Worst Marine and others are all "straight
thread" with straight thread tightening nuts. The sea-cocks that go
on these thru-hulls are also straigh threaded, but are designed to be
bolted [ usually 3 bolts ] through the hull also. It would seem that
for a fiberglass hull the less holes the better.

So many people put a tapered thread ball valve [seems like all ball
valves are tapered threaded] on to the straight thread thru-hull. Not
a good idea.

T. Sanders
S/V Cimba

The reason you can't find a tapered thread on a thru-hull is because
you don't want tapered threads on a thru-hull. The standard nut on a
thru-hull guarentees that the nut is holding the back of the face of
the thru-hull tight to the hull, the same holde true with the backing
material and nut. Exerting a clamping force on the thru-hull, giving
you a good seal to the hull. The problem with the tapered design would
be that the nut, which might be tight, would be tight to the thru-hull
threads, but may not be exerting any clamping force on the thru-hull
face. The nut could be nice and tight, and the thru-hull might be
loose to the hull.

Tapered thread thru-hulls ?
 

Not sure I understand your reply,,, do you mean to say that tapered
[pipe] threads wouldn't "snug down" like straight threads? Seems like
when I do plumbing around the house that that's the case.

Maybe I should have asked the question of whether anyone makes a
straight threaded ball valve.

Trent
S/V Cimba

(John) wrote in message . com...
(Trent D. Sanders) wrote in message . com...
Does anyone know of a source for BRONZE tapered thread [pipe thread]
thru-hulls?

The thru-hulls sold by Worst Marine and others are all "straight
thread" with straight thread tightening nuts. The sea-cocks that go
on these thru-hulls are also straigh threaded, but are designed to be
bolted [ usually 3 bolts ] through the hull also. It would seem that
for a fiberglass hull the less holes the better.

So many people put a tapered thread ball valve [seems like all ball
valves are tapered threaded] on to the straight thread thru-hull. Not
a good idea.

T. Sanders
S/V Cimba

The reason you can't find a tapered thread on a thru-hull is because
you don't want tapered threads on a thru-hull. The standard nut on a
thru-hull guarentees that the nut is holding the back of the face of
the thru-hull tight to the hull, the same holde true with the backing
material and nut. Exerting a clamping force on the thru-hull, giving
you a good seal to the hull. The problem with the tapered design would
be that the nut, which might be tight, would be tight to the thru-hull
threads, but may not be exerting any clamping force on the thru-hull
face. The nut could be nice and tight, and the thru-hull might be
loose to the hull.

Tapered thread thru-hulls ?
 

Comments below:
"Trent D. Sanders" wrote in message
om...
Not sure I understand your reply,,, do you mean to say that tapered
[pipe] threads wouldn't "snug down" like straight threads? Seems like
when I do plumbing around the house that that's the case.

Maybe I should have asked the question of whether anyone makes a
straight threaded ball valve.

Trent
S/V Cimba

I'll try to explain what he meant. As you know tapered threads are tapered.
They are used for pipe fittings because as they are screwed together the
tapers come closer and closer together until all the space between the
threads is taken up and the fitting becomes tight. The threaded area can
only be so long as it tapers at a constant rate. If you tried to make a
tapered thread thru hull it wouldn't work because the threads at the top
would be way too loose and weak with not enough thread contact, and at the
bottom too tight for the ring to turn far enough to hold the thru hull tight
to the hull.

Make sense? You could probably get a plumber to re-cut the straight threads
into tapered threads on the top of your thru hulls but it would be better to
use real seacocks with regular thruhulls threaded straight in as explained
in an earlier post.
--
Ken Heaton & Anne Tobin
Cape Breton Island, Canada
kenheaton AT ess wye dee DOT eastlink DOT ca