Fixing cracked filter canister? Ideas?

[rwhite692]

Well, here's the latest thing to break around the ol' Ponderosa. It's always something...

Pool pump DE filter canister. Upper and lower canister sections are held together by a band clamp and O-ring. It’s around 7 yrs old.

The lower canister section has developed a stress crack (and it leaks when the system is pressurized). The crack is about 1.5" long. Thankfully, the crack does not extend up into the sealing area where the band clamp and o-ring are located. (That area of the housing is much thicker material).

My intention is to replace the canister with a new one ($$$), but I need an interim fix to get me through the rest of this season. (Next Spring I intend to cut out and replace a whole bunch of the PVC plumbing, and re-do this whole setup, anyway).

The canister material is around ¼” thick, and appears to be a fiberglass-related product, but it is not your conventional, i.e., laid-up or chopper-gun fiberglass (looks like a fiber-reinforced, injection molded plastic?)

The reason I say it definitely contains fiberglass, is that the upper dome section (where it has weathered) shows tiny exposed surface fibers (I’ve gotten the ol' “fiberglass itch” from my forearm coming into contact with it).

I’m thinking that I will remove the lower canister, and lay it on its side. Grind the inside surface for around a 4-5” area around the crack, to give it some “tooth”. Clean well w/acetone and apply conventional chopped fiberglass/polyester resin repair method, building up about a ¼” thick patch, over the crack.

Any other suggestions or recommendations appreciated!

 

[fourfeathers]

Need details, but perhaps I can make you a deal on my old filter? What model, etc. Also, pics of the top and housing.

 

[Dustoff]

Don't scrap it...JB weld it!

 

[rwhite692]

Hi Fourfeathers...It's a Pentair (Formerly PacFab) FNS Plus, 60 sqft.

 

[38Chevy454]

I think your fiberglass repair sounds like a good plan. That is what I was going to suggest and you laid out exactly what I would do.

 

[DIC]

I know a guy that repaired his with fiberglass, far as I know it worked .......

 

[66HertzClone]

You might consider putting a strap of some sort around that area to keep the pressure from putting pressure on your repair. Too bad hose clamps are not that long, but things like the strap to hold an antenna support to a chimney might work.

 

[JSBriggs]

Drill the ends of the crack to keep if from spreading, then JBweld it to seal it up.

-Jeff

 

[rwhite692]

Thanks for your inputs, gentlemen.

JSBriggs that is indeed a good idea...I will drill the ends with about an .040" to stop the crack progression.

I had thought about trying good ol' JB Weld on this repair...What has me concerned is the amount that the tank actually "grows" under pressure...You can actually see it flex just a bit, when the system is initially pressurized (which is probably why it eventually developed a crack).

So that's why I'm thinking that my patch coverage area on the inside surface might need to be pretty large.

 

[fourfeathers]

Mine is only 24 sq ft. If you find out it would help, let me know! Looks similar, but your top is MUCH taller.
What is max psi, 14?

 

[Rudyjr]

The fiberglass inside patch would be the best way to go. I would use a piece of woven mat instead of chop, just my 2 cents.

 

[sdowney717]

get the Versachem plastic welder epoxy in a black tube from Autozone
it works on all sorts of plasticky items.
very strong solvents are in this

have not had a failure yet. Even used it on a plastic radiator

 

[Lotek]

The best thing I have found for glass repair is West Systems Gflex epoxy, stuff sticks to anything, you can get a kit with filler for about $20, is flexible, and is stronger than most anything else out there. The kit is enough for a bunch of small repairs. Use it with a couple layers of cloth and it will be stronger than the original. Regular polyester resin isn't as strong and doesn't bond as well to old glass, The stuff in the double tube is a lot more $$ for a lot less glue, and you are paying for filler to make it thick. The west comes thin, but you add filler as nec. No affiliation, just a happy customer.

 

[burnitwithfire]

I’m thinking that I will remove the lower canister, and lay it on its side. Grind the inside surface for around a 4-5” area around the crack, to give it some “tooth”. Clean well w/acetone and apply conventional chopped fiberglass/polyester resin repair method, building up about a ¼” thick patch, over the crack.

Any other suggestions or recommendations appreciated!

Sounds like a good plan. You should drill holes at each ends of the crack to prevent it from spreading. Then you groove and sand the crack in a V shape to give the fiberglass patch a better hold. You should do the same on the outside. Make sure your resin oozes from the crack so one side has a grip on the other side for maximum strenght. This is what I do when I fix cracked bumpers.

Use 80 grit sandpaper.

 

[Thorold]

Marine Goop from Canadian Tire.

I use that S&^t on everything ......

 

[Dan in Pasadena]

JB Weld it.

 

[rwhite692]

Thanks to all for your inputs.

Lotek thanks for the recommendation on the G/Flex. I have used various West products before with great results.

 

[southpier]

groove the crack in a reverse "v" with the opening narrower than the inside of the goove (just like you would do for a concrete repair) with a ball cutter on a dremel tool. fill with either MarineTex or aforementioned JB Weld.


http://www.marinetex.com/

 

[rwhite692]

Southpier, I had forgotten all about Marinetex. That stuff has saved the day for me quite a few times.

 

[Cman]

I have a FSN60 and mine cracked around the same area. I tried marine epoxy putty and worked for about 3 days. I also tried a bondo repair kit and that leaked too. Please let me know if the fiberglass patch wokrs out for you. Thanks.

 

[Northstar9126]

I would try gluing a piece of inner tube to the inside. pressure will force the tube into the crack to keep it from leaking.

 

[ZRX61]

I'd just throw a piece of stainless in the slip roller, curve it to match the inside of the filter & glue it in place.

 

[rwhite692]

Thanks all for your suggestions. I think I will give marinetex a shot, picked some up. I should be able to do that repair without disconnecting the whole tank assembly. If that (quick) repair works, then, great, if not then I'll rip it all apart and go all the way into a bigger repair. Or just replace the tank.

 

[rwhite692]

OK so I finally had a chance to work on this when I got home today. I think my fix will work. Many thanks for all of your suggestions.

decided to get a small Marine-Tex kit:

I decided to remove the lower tank section and lay it on it's side, since trying to do it with the tank vertical, the marine tex would just run down.

Drilled a couple holes at the ends of the crack to stop further spreading, as was suggested (red arrows) then ground the area thoroughly:

Inspired by ZRX61s suggestion, I decided to make a stainless steel patch plate to overlay the marine-tex. Rummaging around in my scrap pile I found a small piece of 20 ga.

I bent it into a gentle curve to match the contour of the inner wall of the tank, then hit the mating surface with the grinder to give it some "tooth":

Then scrubbed the whole area, and the patch w/acetone....marked the outline of where the patch will go and laid down a nice big puddle of marine tex. Squished the plate down into it, and brushed a little around and up over the perimeter.

Will re-assemble tomorrow and see what happens!