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#1
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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 |
#2
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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 |
#3
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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 |
#4
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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 |
#5
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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 |
#6
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Tapered thread thru-hulls ?
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#8
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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 |
#9
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Tapered thread thru-hulls ?
Thank you for the info,,,,,,,,, now I have a clear picture of the
situation. Which "pains me" because when I had all [9] thru-hulls and valves replaced on my Islander 29', the yard, the yard mechanics, the salespeople [at Worst Marine] ALL said to put tapered thread ball valves onto the straight thread thru-hulls. Well, I may be an "expert" at flying a 747 but I don't [didn't] know squat about thru-hulls and valves/seacocks. So I let them go ahead. Only later did I read in 'Good Old Boat' [best magazine out there!] that this is a "no no". Live and learn,,,,,,, now I'll have to have it done over, but properly this time. Cheers, Trent S/V Cimba "Ken Heaton" wrote in message ... 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. |
#10
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Tapered thread thru-hulls ?
Thank you for the info,,,,,,,,, now I have a clear picture of the
situation. Which "pains me" because when I had all [9] thru-hulls and valves replaced on my Islander 29', the yard, the yard mechanics, the salespeople [at Worst Marine] ALL said to put tapered thread ball valves onto the straight thread thru-hulls. Well, I may be an "expert" at flying a 747 but I don't [didn't] know squat about thru-hulls and valves/seacocks. So I let them go ahead. Only later did I read in 'Good Old Boat' [best magazine out there!] that this is a "no no". Live and learn,,,,,,, now I'll have to have it done over, but properly this time. Cheers, Trent S/V Cimba "Ken Heaton" wrote in message ... 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. |
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