Bulkheads on the bottom

[guserto4]

Are the any tricks to using bulkheads on the bottom of the tank? I worry about the possibility of a leak some day and am wondering if anyone uses a grease or lube or jelly or glue of some sort to "aide" the seal of the gasket. Would be nice to have the option to remove them, so glue (unless it still breaks with some effort) seems out.

Do you guys use anything or is the rubber gasket always enough?
(Going in acrylic tank)

 

[ca1ore]

I don't like bulkheads that are 'open' to the full volume of the tank. I did have a glass tank for awhile back that had one that never leaked in the 20 years I owned it, but I siliconed it in and didn't ever try to remove it. I wouldn't do it again.

 

[guserto4]

Even for closed loop? That's what I'm looking at

 

[das75]

I've got 8 bulkhead on the bottom and not a drip since setup in 2006, flange and gasket on the wet side. Though I did a very thin film of silicone on the gasket before assembling, reading after, if done properly wasn't needed. I made sure the bulkhead face was smooth as can find some with ridge from casting.

 

[ca1ore]

Even for closed loop? That's what I'm looking at

I wouldn't do it. OK, scenario time .... you install your bulkheads according to conventional wisdom. Then at some point, you bump a pipe and one of them starts to drip. Sometimes tightening helps, but often it either does not or makes things worse. What would you do? Answer is you'd have to drain the tank and reseat the bulkhead. No thanks!

 

[ca1ore]

I've got 8 bulkhead on the bottom and not a drip since setup in 2006, flange and gasket on the wet side. Though I did a very thin film of silicone on the gasket before assembling, reading after, if done properly wasn't needed. I made sure the bulkhead face was smooth as can find some with ridge from casting.

I'd actually suggest some silicone is actually a good idea on a bulkhead installed in such as risky spot. My 180 had one in the bottom that I glued in and I have it on good authority that it's still good after 25 years. I would not, however, install one that way without silicone.

 

[Aquatron]

Never had a problem with many tank's drilled on bottom but i would suggest using sch. 80 bulkheads Remember "Nothing to fear but fear itself":dance:

 

[sleepydoc]

Schedule 80 bulkheads shouldn't be necessary, if they're installed properly. Having bulkheads at the bottom of the tank shouldn't be an issue, either. Virtually every single corner flow tank with a durso or Herbie is experiencing virtually the exact same pressure. The main thing is to install them properly.

 

[Aquatron]

Sleepydoc your responce about sch. 80 bulkheads vs ABS one's tell me you have never used sch. 80 bulkheads? While they may not be necessary there is a difference between them with quality and also when installing you can FEEL sch. 80 bulkheads seal. Not sure many hobbiest worrie about the weight of their DT water on a bulkhead?

 

[mfinn]

I am plumbing a tank for a friend that had a bottom closed loop designed for her by the tank maker.
I don't really care for bottom drilled closed loops, they just make me a little nervous.
I did insist the holes be drilled for schedule 80 bulkheads.

 

[Gorgok]

With it being an acrylic tank id say you are fine with enough torque and nothing else. You don't have to worry about breaking the tank, just the bulkhead, if you tighten too much...

Checking and fixing the flange to be free of any flashing is good too.

I made a 70mm socket for my bulkhead install, out of pvc pipe. It was really handy to get a good grip on the nuts.

 

[ca1ore]

Schedule 80 bulkheads shouldn't be necessary, if they're installed properly. Having bulkheads at the bottom of the tank shouldn't be an issue, either. Virtually every single corner flow tank with a durso or Herbie is experiencing virtually the exact same pressure. The main thing is to install them properly.

Not sure anyone is suggesting it's a pressure issue - I'm certainly not. But bulkheads at the bottom of an overflow present far less dramatic issues should they fail. One, they aren't open to the full volume of the tank, just that water which flows over the weir; and two, removing and reseating is a relatively trivial prices that does not require fully draining the tank.

Regardless, clearly I'm in the minority here. I wouldn't do it, but that's just me.

 

[rwb500]

Regardless, clearly I'm in the minority here. I wouldn't do it, but that's just me.

i agree, it's definitely something I would avoid if possible. The idea of having to completely drain the tank to fix something is bothersome to me. I like to have flexibility. That being said, if I had to, I would get some high quality bulkheads, clean everything really well, use some silicone for good measure, and make sure the plumbing never got bumped.

 

[Aquatron]

Many way's, just install a threaded gate valve on your bulkhead and it makes working on close loop piece of cake. It's just a choice i agree but some don't enjoy pieces of equipment and wire's in their DT so bottom drilled gives those another option.

 

[sleepydoc]

Sleepydoc your responce about sch. 80 bulkheads vs ABS one's tell me you have never used sch. 80 bulkheads? While they may not be necessary there is a difference between them with quality and also when installing you can FEEL sch. 80 bulkheads seal. Not sure many hobbiest worrie about the weight of their DT water on a bulkhead?

I haven't used schedule 80 bulkheads, but have used schedule 80 plumbing, and it definitely feels more substantial. My point is that the extra heft is unnecessary for our purposes. ABS bulkheads are more likely to crack if overtightened or if too much torque is placed on the bulkhead, but those are things that you shouldn't be doing to any bulkhead whether it's ABS or schedule 80. Beyond that, it's simply a matter of putting adequate pressure on a rubber gasket to seal it. That's something an ABS bulkhead can do perfectly well.

Not sure anyone is suggesting it's a pressure issue - I'm certainly not. But bulkheads at the bottom of an overflow present far less dramatic issues should they fail. One, they aren't open to the full volume of the tank, just that water which flows over the weir; and two, removing and reseating is a relatively trivial prices that does not require fully draining the tank.

Regardless, clearly I'm in the minority here. I wouldn't do it, but that's just me.

I actually thought that's what your were alluding to. Either way, my (unscientific) impression of bulkhead failures is that the vast majority occur early on as a result of improper installation. Random failures in 'established' systems are fairly rare, and among those, the vast majority are slow leaks; catastrophic failures are exceedingly rare. I wouldn't use it as a determinant of bulkhead placement personally.

Everyone has their own tolerance for risk, however, so there's nothing inherently wrong with saying the risk of a bottom bulkhead is too great. I'm just not sure that it's appreciably greater than one placed half way down on the back wall.

 

[uncleof6]

6 one way, half dozen the other. In the end, it depends on what you are doing. In any case, sch80 bulkheads are a waste of time for our purposes, and I can snap them off just as easily as sch40 bulkheads.