Reverse bulkheads?

malx

malx

Active member
Hi, Everyone.

So I'm working on a DIY Sump Build. When doing bulkheads, the general consensus is that the flange side goes on the inside of the tank (since that's the nicer looking side) and the washer needs to go inside the tank as well this way the water does not creep through the little screw pathways and leak out. For my sump build, I need to actually have the flange reversed and have that outside the container with the screw side in. I'd put the washer on the outside so that the water does not sneak under the screw again and out through the flange. Anyone ever do this? Anyone have issues?

Let me know,
Joey
 
I did this same thing with my ATS. Just totally reverse the bulkhead(flange and gasket on the dry side), working fine for me, but of course it's not under very much pressure either.
 
That makes sense.

It just goes against my nature to put a gasket on the outside of a container. Before I knew better, I poorly setup a sump once with the flange on the outside and the gasket and threads on the inside. I dealt with the thread leaking issue with lots of Teflon tape (like I said...poor design).
 
And teflon tape is for metallic(metal) threaded connections only and should never be used on PVC or any other plastic threaded fitting ;)
Instead you use a non-hardening thread sealant specifically intended for PVC or whatever plastic it is.. nylon/abs,etc....
 
mcgyvr said:
And teflon tape is for metallic(metal) threaded connections only and should never be used on PVC or any other plastic threaded fitting ;)
Instead you use a non-hardening thread sealant specifically intended for PVC or whatever plastic it is.. nylon/abs,etc....
Click to expand...

Agreed. Like I said, before I knew better.

I don't know if the paste would have stayed put underwater in that case. The tape stopped the leaking through the threads...But again, it was a poor design.
 
mcgyvr said:
And teflon tape is for metallic(metal) threaded connections only and should never be used on PVC or any other plastic threaded fitting ;)
Instead you use a non-hardening thread sealant specifically intended for PVC or whatever plastic it is.. nylon/abs,etc....
Click to expand...

What happens if you use Teflon tape? I have a few connections with it on my main display. It's been 2 years don't know of any issues yet.
 
homer1475 said:
I did this same thing with my ATS. Just totally reverse the bulkhead(flange and gasket on the dry side), working fine for me, but of course it's not under very much pressure either.
Click to expand...

Thanks! This won't be under pressure either. I'm using two garbage cans as a sump and need the water to travel from one to the other, it will just trickle over through the 2" PVC hole/pipe.
 
malx said:
What happens if you use Teflon tape? I have a few connections with it on my main display. It's been 2 years don't know of any issues yet.
Click to expand...

NOTHING: We just went through this.

In short, the reason you don't use Teflon tape on PVC is that it doesn't need it. It's essentially a filler and a lubricant, and most people tend to over tighten it and THAT'S what causes leaks. That and people wrapping the hell out of it and then forcing the screw fitting down which is why it may leak. A few turns will do, i.e, just enough to cover the threads. All it needs is the "filler" part to stop leaks so as long as you don't over tighten it, you will be fine and it will stop leaks.

There are more reefers out there using Teflon tape than not. Yes the non-hardening filler works well, but so does Teflon tape when used correctly
 
PTFE and Teflon are the same thing.

PVC fitting threads are tapered, so they don't need it. And the tape can actually cause you to over tighten, cracking the fitting.
 
malx said:
It's not Teflon, it's PTFE tape.
Click to expand...

Teflon is just one of the brand names of Polytetrafluoroethylene (PTFE)..
PTFE = Teflon

Teflon decreases friction can can lead to overtightening of the joint thus causing failure..
Its been used by many people incorrectly for years and many times it doesn't cause any problems and many..many times it does..

Here is an article written by one of the largest manufacturers of PVC fittings..
http://www.lascofittings.com/threads
 
mcgyvr said:
Teflon is just one of the brand names of Polytetrafluoroethylene (PTFE)..
PTFE = Teflon

Teflon decreases friction can can lead to overtightening of the joint thus causing failure..
Its been used by many people incorrectly for years and many times it doesn't cause any problems and many..many times it does..

Here is an article written by one of the largest manufacturers of PVC fittings..
http://www.lascofittings.com/threads
Click to expand...

Thanks. I most certainly don't overtighten my joints, I know that could be bad. I am going to use a very small amount of tape with this new build just because that's what I've always done and I don't want to run any risk of leaking. I did just use one layer on my fittings for my main display and no leaks after two years.
 
nereefpat said:
PTFE and Teflon are the same thing.

PVC fitting threads are tapered, so they don't need it. And the tape can actually cause you to over tighten, cracking the fitting.
Click to expand...

I thought that's what I said but ok. Use it. Don't use too much and don't over tighten. You will be fine.
 
windlasher said:
I thought that's what I said but ok. Use it. Don't use too much and don't over tighten. You will be fine.
Click to expand...

There was only 2 minutes between your post and theirs so I'm quite positive they didn't even see your response.. and nothing wrong with having multiple matching responses..
To me thats the only way I accept any data from the internet.. Never trust a single source..
 
All this bickering back and forth about teflon or PTFE tape(FYI they are the same thing), you think someone could actually answer the ops question?


Not a single post in this thread answers the OP's question. He didn't ask where the gasket went or whether to use tape or paste, or what the difference between the 2 is. His specific question was whether he could flip a bulkhead so the flange was on the dry side.

One would think that somewhere in 18 posts someone could have answered the original question.Yes I understand this is a DISCUSSION board, but one would think the original question would get answered.
 
You already addressed his question in your post #3..
So the question was answered by at least one person.. And as you said.. This is a discussion board so discussions occurred...

Obviously you can mount it whichever way you want..
Its just 2 pieces of plastic..
As long as you put the gasket on the correct side all will be just fine..
 
homer1475 said:
All this bickering back and forth about teflon or PTFE tape(FYI they are the same thing), you think someone could actually answer the ops question?


Not a single post in this thread answers the OP's question. He didn't ask where the gasket went or whether to use tape or paste, or what the difference between the 2 is. His specific question was whether he could flip a bulkhead so the flange was on the dry side.

One would think that somewhere in 18 posts someone could have answered the original question.Yes I understand this is a DISCUSSION board, but one would think the original question would get answered.
Click to expand...

By my read... several people answered his first question and then several people answered his second question followed by his third which was about Tape. Who's bickering? :bounce3: We are discussing various takes on plumbing.
 
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