Doesn't rigid PVC connected to your glass tank make you nervous?

[kysard1]

I am planning a 50 gallon tank. I see all these photos of people connecting PVC to there bulkheads on glass tanks. This can put an incredible amount of torque on your bulkhead, I would be afraid of cracking the tank. I have used 3ft of PVC as a torque multiplier to remove 550 ft/lbs torqued bolts.

1. You could use a pipe mount to fixture the pipe to your stand. But what happens when your tank settles on the stand 1 mm? Now your bulkhead is being torqed.

2. Use no pipe mount. Now you have vibrations chipping away at the bulkhead.

3. Use spa-flex PVC. This doesn't help with vertical movement, spa-flex is completely rigid longitudally. In fact bending the spa-flex can put more stress on your bulkhead than standard PVC.


Best bet: Use a small piece of pipe foam insulation in between the PVC and the pipe mount (strap). Do not make the pipe strap tight, just enough clamping force to stop vibration. You want the pipe to be able to move verticaly.

[Worldwithin]

I would imagine that if it was such an issue, people would be commenting about it more often. From my experience, I have never had any issues with PVC causing stress fractures or any damage to any of my tanks over the years. The only thing I can think of that would cause that is if you had some serious weight issues forcing the PVC to flex against your bulkhead. Now on thinner glass, I can see this occuring, but the only time I have ever seen glass crack at a bulkhead was when I was moving a glass 39gal sump and I accidently nuged a bulkhead with my shoe, causing it to flex and crack the glass. I am sure that others have had situations that caused glass to crack, but that was the only time I have had it happen to me.

I think that if you prevent the bulkhead from flexing the glass and increasing the angular load, you should be fine. Keep the load either vertical or horizontal to the glass, and I believe your glass will hold quite well.

[Alto]

Generally speaking there is virtually no torque put on the bulkhead connections. On the pump side when you run rigid pipe the weight of the pipe etc is resting on the pump, not pulling on the bulkhead. On the drain side most people I have seen have the drain lines resting on something or actually mounted to the stand, again the weight is resting on whatever its mounted to not on the bulkhead. Given the hundreds of thousands of people using bulkheads with rigid pipe and that I have yet to hear a single story of someones tank breaking simply from the weight or torque of the installed pipe, I would say your chances of having a problem are about as good as winning the lottery. The only time I have heard of people breaking their tanks at the bulkhead was people being stupid and torquing the pipe to get it to go somewhere other then where it wanted to be.

[BeanAnimal]

Yeah, this is pretty much a non issue.

Random thoughts in no order:

FWIW you still have to use quite a bit of force on a 3' cheater bar to remove a 550fp fastner.

If you tank settles THAT much, you have real problems.

The bulkhead gasket allows for some movement and shock absorbtion.

PVC is rather soft and also allows for some damping effect.

Glass is VERY STRONG, esp when we are talking about larger tanks.

SpaFlex is a shock absorber as well as being flexible enough to absorb some lengthwise stress.

Plumbing SHOULD be secured, but most folks don't bother.

Most of the time if it IS secured, it is not done so in a rigid manner.

As mentioned if the forces are in line with the plane of the glass and not angular, then there is not much torque to transfer.

YES if you try hard enough you can break the tank around the bulkhead.

[BruiseAndy]

Just curious what schedule pvc handled being a 3foot cheat bar?

[BeanAnimal]

I didn't want to go there

I (like many others) have broken my share of wrenches and ratchets with 3' or so cheater bars. I still use the old school boxed end to open end wrench trick to. That separates the cheapies from the real deal, very quickly!

500+ ft/lb of torque with a piece of 3' plastic is...

Anway VERY FEW people understand that STANDARD wrench lengths are designed so that the average man can apply the maximum rated torque to that size bolt (of course differnet bolt grades, thread types etc come into play). Adding a cheater usually exceeeds both the bolts rated torque, exceeds the force needed to round the faces of the bolt or nut, and usually exceeds the design spec of the tool being used.

I have seen some pretty damn scary cheater bar accidents. "Hey lets put a 6' cheater on the end of that torque multiplier and get this 4" bolt loose. If we cant pull hard enough lets all stand on it. If that is not enough lets chain the cheater to the equipment and pull it!"

Safety glasses anybody? Full body armor anybody?

[fishnfst]

Originally posted by BeanAnimal
I didn't want to go there

I (like many others) have broken my share of wrenches and ratchets with 3' or so cheater bars. I still use the old school boxed end to open end wrench trick to. That separates the cheapies from the real deal, very quickly!

500+ ft/lb of torque with a piece of 3' plastic is...

Anway VERY FEW people understand that STANDARD wrench lengths are designed so that the average man can apply the maximum rated torque to that size bolt (of course differnet bolt grades, thread types etc come into play). Adding a cheater usually exceeeds both the bolts rated torque, exceeds the force needed to round the faces of the bolt or nut, and usually exceeds the design spec of the tool being used.

I have seen some pretty damn scary cheater bar accidents. "Hey lets put a 6' cheater on the end of that torque multiplier and get this 4" bolt loose. If we cant pull hard enough lets all stand on it. If that is not enough lets chain the cheater to the equipment and pull it!"

Safety glasses anybody? Full body armor anybody?

I just spit Ice Tea all over my computer after reading this .... I was wondering the same thing about a 3' pvc cheater for a 550ft/lb's amount of torque... I've broken pins on 3/4" drive cheater bars trying to break something loose that wasn't even torqued to 500+ft/lbs

[ccorpse27]

Originally posted by BeanAnimal
I didn't want to go there

I (like many others) have broken my share of wrenches and ratchets with 3' or so cheater bars. I still use the old school boxed end to open end wrench trick to. That separates the cheapies from the real deal, very quickly!

500+ ft/lb of torque with a piece of 3' plastic is...

Anway VERY FEW people understand that STANDARD wrench lengths are designed so that the average man can apply the maximum rated torque to that size bolt (of course differnet bolt grades, thread types etc come into play). Adding a cheater usually exceeeds both the bolts rated torque, exceeds the force needed to round the faces of the bolt or nut, and usually exceeds the design spec of the tool being used.

I have seen some pretty damn scary cheater bar accidents. "Hey lets put a 6' cheater on the end of that torque multiplier and get this 4" bolt loose. If we cant pull hard enough lets all stand on it. If that is not enough lets chain the cheater to the equipment and pull it!"

Safety glasses anybody? Full body armor anybody?

gotta do what you gotta do.

[BeanAnimal]

Yup... I spent close to 15 years in underground coal mines. It is amazing what you can do with a cheater bar and some thought.

[Worldwithin]

Originally posted by BeanAnimal
Yup... I spent close to 15 years in underground coal mines. It is amazing what you can do with a cheater bar and some thought.

Ok, now that is a scary thought....

=P