EcoRenovator  

Go Back   EcoRenovator > Improvements > Other Improvements
Advanced Search
 


Blog 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 01-12-17, 10:02 PM   #11
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,004
Thanks: 303
Thanked 723 Times in 534 Posts
Default Non-Tapered Threads

Daox,

I had a similar problem with a heat pump project.

Standard pipe thread is tapered and relies on a progressive interference fit to work.

There are other pipe thread systems that do not rely on tapered, progressive interference to work. Instead, they use a flat compression washer. The straight threads supply force to compress the washer.


If you were crossing systems, it would feel gritty, because very small bits of thread faces were being sheared off by your struggle to make it seal.

One give-away is that the thread shoulder (male and female) has a precision-machined surface.

There's a good chance that the damage to the threads is not completely fatal yet. If the machined surface of the shoulder is still intact and undamaged, you may be able be successful.

Of course, you need the proper straight-thread part and the proper compression washer.

If the damage has been too severe, there's epoxy.

Best,

-AC_Hacker

Attached Thumbnails
Click image for larger version

Name:	Straight-Thread-Versus-Tapered-Thread.jpg
Views:	3484
Size:	346.2 KB
ID:	7537  
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...
AC_Hacker is offline   Reply With Quote
Old 01-13-17, 08:29 AM   #12
Daox
Administrator
 
Daox's Avatar
 
Join Date: Aug 2008
Location: Germantown, WI
Posts: 5,525
Thanks: 1,162
Thanked 374 Times in 305 Posts
Default

Thanks for the tip AC Hacker. I'm aware of this. The unit we were working on had male NPT threads on the outside. They were definitely tapered.
__________________
Current project -
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
&
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Daox is offline   Reply With Quote
The Following User Says Thank You to Daox For This Useful Post:
emilyhendrix (02-21-17)
Old 01-13-17, 10:30 AM   #13
AC_Hacker
Supreme EcoRenovator
 
AC_Hacker's Avatar
 
Join Date: Mar 2009
Location: Portland, OR
Posts: 4,004
Thanks: 303
Thanked 723 Times in 534 Posts
Default

When you said that "half the joints leaked", what are you referring to? Your heater only has two, IN an OUT, right?

Are they leaking?

Are half of all the joints you put together leaking?

This is very strange.

It sounds like you have been invaded by a different Physics that doesn't apply in the rest of the universe..

Maybe you should go copper at the heater, and switch to PEX ASAP.


-AC
__________________
I'm not an HVAC technician. In fact, I'm barely even a hacker...
AC_Hacker is offline   Reply With Quote
The Following User Says Thank You to AC_Hacker For This Useful Post:
emilyhendrix (02-21-17)
Old 01-13-17, 12:30 PM   #14
gasstingy
Journeyman EcoRenovator
 
Join Date: Feb 2010
Location: Arab, AL
Posts: 491
Thanks: 109
Thanked 49 Times in 43 Posts
Default

Gasoila is used in the gas station business for installing underground tank fittings and more. You could likely find a petroleum equipment supplier (relatively) locally that would have it.

Hope this helps

Last edited by Daox; 01-13-17 at 01:15 PM..
gasstingy is offline   Reply With Quote
The Following User Says Thank You to gasstingy For This Useful Post:
emilyhendrix (02-21-17)
Old 01-13-17, 12:53 PM   #15
Daox
Administrator
 
Daox's Avatar
 
Join Date: Aug 2008
Location: Germantown, WI
Posts: 5,525
Thanks: 1,162
Thanked 374 Times in 305 Posts
Default

We made a few other connections off the heater to ball valves for flushing the heater with vinegar.

In the end, we switched from the threaded fittings to compression fittings as that was another option that came with the heater. Those sealed up just fine.
__________________
Current project -
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
&
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Daox is offline   Reply With Quote
The Following User Says Thank You to Daox For This Useful Post:
emilyhendrix (02-21-17)
Old 01-13-17, 02:08 PM   #16
oil pan 4
Land owner
 
Join Date: Nov 2012
Location: NM
Posts: 1,026
Thanks: 12
Thanked 127 Times in 107 Posts
Default

To get 3/4npt fittings to properly seal it takes 100ft.lb, I have found that most npt fittings that leak are not any where near tight enough.
oil pan 4 is offline   Reply With Quote
The Following User Says Thank You to oil pan 4 For This Useful Post:
emilyhendrix (02-21-17)
Old 01-24-17, 02:58 PM   #17
1234enough
Lurking Renovator
 
Join Date: Jan 2017
Location: uk
Posts: 3
Thanks: 0
Thanked 1 Time in 1 Post
Default

I use Loctite 55, its a cord with PTFE or the like on the cord, seems to keep on the thread better than PTFE tape and you can realy feel it's there when tightening up the joint.
1234enough is offline   Reply With Quote
The Following User Says Thank You to 1234enough For This Useful Post:
emilyhendrix (02-21-17)
Old 02-06-17, 03:23 AM   #18
rclark762
Lurking Renovator
 
Join Date: Jan 2017
Location: CA
Posts: 4
Thanks: 0
Thanked 1 Time in 1 Post
Default

Quote:
Originally Posted by stevehull View Post
Daox,

Don't feel bad . . . .

Teflon pipe tape works great if the threads are in good shape. More recently, the quality of metal pipe threading has gone to hell.

I never had leaks, in the past, but I get them regularly now if I just use teflon tape.

I still use teflon tape on the outside threads, but now always use pipe "dope" on the inside threads. A bit more time, but NO leaks.

Hope this helps.

Steve

ps pipe dope is messy and nasty . . .
+1 to this comment.
rclark762 is offline   Reply With Quote
The Following User Says Thank You to rclark762 For This Useful Post:
emilyhendrix (02-21-17)
Old 02-25-17, 10:09 AM   #19
creeky
Journeyman EcoRenovator
 
creeky's Avatar
 
Join Date: Jun 2011
Location: a field somewhere
Posts: 304
Thanks: 64
Thanked 44 Times in 31 Posts
Default

Quote:
Originally Posted by oil pan 4 View Post
To get 3/4npt fittings to properly seal it takes 100ft.lb, I have found that most npt fittings that leak are not any where near tight enough.
When I fitted propane into my camp I could not believe how hard I had to lock those fittings down. And that was with pipe goop. Basically it took every ounce of muscle I had and then going back the next day and doing it again.

Thx steve for the idea to wrap the inner threads and goop the outer. I will try that next time.

__________________
Current projects
Chevy Volt battery pack conversion

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Blog that is down right now but will return
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Business where I sell solar stuff
[url]https://www.bobolinksolar.com
creeky is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:20 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design