My opinion is that there is no acceptable fix for a cracked filter.
Does anyone have any methods that they think would provide a good fix?
Does anyone have any methods that they think would provide a good fix?
Can a cracked filter be fixed?
- Thread starter JamesW
- Start date
A safe repair would likely exceed the cost of a new filter, and very, very few people, even professionals, would have any idea how to go about such a repair. Because of that, the risk of shrapnel and the fact that the filter has already cracked once, I'm on the no repair side.
ZcottD
0
I could see patching a small crack for a season and trying to make it work if a new filter just wasn't in the budget. Use a water proof, strong epoxy. I wouldnt want to patch it with anythign that could get clogged in the plumbing if it failed.
James,
Bomb Disposal Rule # 1 says "no to cracked filter repairs"
I'm with you on this one...
Jim R.
Bomb Disposal Rule # 1 says "no to cracked filter repairs"
I'm with you on this one...
Jim R.
I agree 100%. Once the vessel is compromised there's virtually no way to repair it. Even if it could be repaired the cost of the repair would exceed the cost of a new vessel.
My policy is to never recommend any repair of a cracked filter vessel, no matter how small the crack seems to be. There are lots of things that can be repaired, but a definite crack isn't one of them.
My policy is to never recommend any repair of a cracked filter vessel, no matter how small the crack seems to be. There are lots of things that can be repaired, but a definite crack isn't one of them.
CJadamec
TFP Expert
Here's a lil fun math next time somebody wants to repair a crack in a pressure vessel.
Lets say average filter pressure is 15psi. So for every square inch of surface area of filter housing there is 15 pounds of force pushing out on it. There are 144 square inches in every square foot.
15 x 144 = 2160 pounds of force per square foot.
In a 20" sand filter I'm going to estimate (no real dimensional measurements taken) there is roughly 15 square feet of surface area. That's based on the assumption of a 20" diameter cylinder 24" tall.
So that un assuming little thing out by everyones pool is containing about 30,000 pounds of force. But the likely hood of the whole filter shattering all at once is pretty slim so that 30k number is pretty meaningless.
The meaningful number is that 2160 number. Its not so unheard of for a large piece say around 1 square foot in size to come of in a failure propagated by a crack. What ever happens to be within about 24" of that piece when it lets go is going to get hit with about a ton of force. That's enough to knock a grown man down and break all kinds of expensive pool equipment.
Pressure vessels are not toys.
Lets say average filter pressure is 15psi. So for every square inch of surface area of filter housing there is 15 pounds of force pushing out on it. There are 144 square inches in every square foot.
15 x 144 = 2160 pounds of force per square foot.
In a 20" sand filter I'm going to estimate (no real dimensional measurements taken) there is roughly 15 square feet of surface area. That's based on the assumption of a 20" diameter cylinder 24" tall.
So that un assuming little thing out by everyones pool is containing about 30,000 pounds of force. But the likely hood of the whole filter shattering all at once is pretty slim so that 30k number is pretty meaningless.
The meaningful number is that 2160 number. Its not so unheard of for a large piece say around 1 square foot in size to come of in a failure propagated by a crack. What ever happens to be within about 24" of that piece when it lets go is going to get hit with about a ton of force. That's enough to knock a grown man down and break all kinds of expensive pool equipment.
Pressure vessels are not toys.
Since you are dealing with a vessel designed to withstand pressurization up to a defined point, any cracks that occur without having reached that pressure limit indicate a structural failure of the vessel. It is very rare for a filter under normal operation to be pressurized to the extent of failure, and you would more likely see a catastrophic failure (explosion) rather than a crack. When you see a small crack in a filter vessel it is likely a result of prolonged UV exposure, abuse (such as striking it with a hammer to loosen stuck pieces) or a manufacturing defect that has weakened over time. However it was caused, the structural integrity of the vessel has been compromised and cannot be restored.
If the vessel has cracked prior to reaching the limits of its pressurized capacity, why would a fiberglass or epoxy patch which has not been pressure tested at all be seen as a safe repair?
Replace the filter.
If the vessel has cracked prior to reaching the limits of its pressurized capacity, why would a fiberglass or epoxy patch which has not been pressure tested at all be seen as a safe repair?
Replace the filter.
- May 23, 2015
- 24,450
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I also vote NO to fixing it with a patch. Just too dangerous. Yes, a new filter is expensive. But so is a hospital stay from a fracture skull and concussion, damaged equipment and/or an injured bystander suing you for personal liability.
There is a reason why pool filters have these types of warning labels on them and in the manuals. I don't know how many people have died from malfunctioning pool filters but I'm sure it isn't zero.
I say no.
It's a pressure vessel.
I wouldn't trust epoxy and fiberglass wrapped around the outside of a cracked propane tank, either
It's a pressure vessel.
I wouldn't trust epoxy and fiberglass wrapped around the outside of a cracked propane tank, either
I too vote that they should never be repaired. Just not something that many homeowners would be able to do remotely safely, and I am not sure any professionals would try either.
In a former life and in a galaxy far, far away I was a DOT certified to conduct hydrostatic testing on SCUBA cylinders. A crack in a,pressure vessel is cause for immediate condemnation. It should be removed from service immediately.
While SCUBA cylinders operate in the 2250 - 3500psi range, I have personally seen the results of a catastrophic failure. In one case the entire front wall of a store was destroyed. In another case the person filling the tank (a friend) had just submerged the tank in a water bath when it let go. The water did absorb most of the force, but he lost about a third of his hand.
Pressure vessels are not toys.
While SCUBA cylinders operate in the 2250 - 3500psi range, I have personally seen the results of a catastrophic failure. In one case the entire front wall of a store was destroyed. In another case the person filling the tank (a friend) had just submerged the tank in a water bath when it let go. The water did absorb most of the force, but he lost about a third of his hand.
Pressure vessels are not toys.
- Jan 4, 2016
- 5,288
- Pool Size
- 44000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
cfherrman
TFP Guide
One thing to remember is different materials react differently to overpressure, pvc pipe will shatter and explode with shrapnel while abs pipe just splits, or vice versa.
I'm still not fixing a pressure vessel, and the steel ones that might have oil in them, such as a air compressor tank, don't well or cut as it might be a bomb as well.
I'm still not fixing a pressure vessel, and the steel ones that might have oil in them, such as a air compressor tank, don't well or cut as it might be a bomb as well.
Awesome posts about the math/science/logic in play as well as the pros (none yet) and cons (repair cost greater than replacement, unsafe/illegal, risking further damage to home/equipment/life, if it failed in one place more are coming) but especially grateful for this post that I believe helps those less familiar with the relevant science reach a common sense answer for themselves:
I agree with the consensus not to repair a cracked filter case if the damage has affected the structural integrity of the case. But it you had something that didn't weaken the case you might be able to plastic weld it. For instance if you took a sand filter and drilled a 1/4" hole in it I think that I could probably patch it up with a hot soldering iron. Especially if you have a piece of plastic scrap as donor material and can get to the damage both inside and out. But a crack that is spreading might be impossible.
Mike.
Mike.
- Jun 12, 2011
- 3,766
- Pool Size
- 19500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pureline Crystal Pure 60,000
Stripped threads on a pressure gauge could be repairable, damage to the filter casing itself, not so much.
Last summer our filter housing developed a crack starting from the lip edge/top and ~3" long near the seam. It was 15 years old. Looked all over the internet for methods of patching the leak. We tried the fiberglass patch, hot soldering iron, plastic weld, marine epoxy, JBWeld. It stopped the leak for only a few hours or slowed it down considerably. The fiberglass patch on both the outside and inside failed. We limped thru each different attempt at patching for several days, only running the pump for several hours a day until we gave up. Needless to say nothing worked so we shut it down for the summer in Mid August since we were headed on vacation out west. We bought a replacement filter on Craig's list before we left but could not use it since the guys laid the filter on its side and rolled it to the car. Sand in the valve regulator (if that's what it's called). This year, cleaned it all up and the replacement works great. A friend took the old cracked filter housing and plans on making it a planter. Probably the only thing its good for. LOL
So, long story short, no use trying to fix the crack. It won't work.
So, long story short, no use trying to fix the crack. It won't work.
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