# Polypropylene Tank Repair



## CaptainForce (Jan 1, 2006)

I have a crack at the top of one of my polypropylene water tanks that I have not been able to secure for years. I heard that there is a new 3M adhesive (3M 72 Spray Adhesive) that may bond to polypropylene. Does anyone have any experience with this product or any success repairing a crack in a polypropylene tank? Take care and joy, Aythya crew


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## brak (Jan 5, 2007)

I think the "official" method of repairing polypropylene items is by welding.


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## LakeSuperiorGeezer (Oct 8, 2010)

Un-official repair I've done is sand surface, then use silicone rubber with 3 or 4 strips of cloth about 3 inches wide, one on top of the other over the crack. This worked for many years on an RV wastewater tank and the repair outlasted the RV. I am not sure if there is anything toxic in silicone rubber.


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## KBuckley (Sep 17, 2008)

A google search on "weld polypropylene" yields reference to a 3M product that claims to bond to polypropylene and polyethylene (DP8005). It also yields info on welding, typically with a hot air welder. Assuming you don't have handy access to a hot air welder I would try a soldering iron with a flat broad tip and practice on some scrap. 

Ken


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## T37Chef (Oct 9, 2006)

Anyone have a recommendation for a "welder" in the Maryland area? My port side water tank has a small crack, just enough to be annoying.


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## GaryHLucas (Mar 24, 2008)

I am in NJ but we do a lot of work in Maryland and I have access to a plastic welder. Not too likely the tanks are polypropylene, most are polyethylene. Polypropylene welds much better. I just welded 2 8" and two 12" vent pipes into 4 12,000 gallon polyethylene waste water tanks in Northeast Maryland. If you are north of Baltimore or so I could probably stop by in the spring and take a crack at it. We have had so so luck with tank repairs though. Sometimes it works, sometimes it don't.

Gary H. Lucas


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## deniseO30 (Nov 27, 2006)

every time this question comes up I give this information and no one seems to believe it works when I say it does. We used it on the poly water tank 3 yrs ago and it's still holding well. the repair was to a stress crack on the tank also.










3M Scotch-Weld DP8005 Acrylic Adhesive


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## brak (Jan 5, 2007)

T37Chef said:


> Anyone have a recommendation for a "welder" in the Maryland area? My port side water tank has a small crack, just enough to be annoying.


I used Maritime Plastics of Annapolis - they built a tank for me. They do welding and seem to be able to create pretty much anything out of plastic.

Not sure if they can "come to you" but they would certainly be able to do the job if you can bring a tank (or, may be, recommend someone who can do it on site).


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## CaptainForce (Jan 1, 2006)

deniseO30 said:


> every time this question comes up I give this information and no one seems to believe it works when I say it does. We used it on the poly water tank 3 yrs ago and it's still holding well. the repair was to a stress crack on the tank also..........


With the product description and reviews for 3M DP8005 Acrylic Adhesive, I'm going to attempt it for my repair. I notice that the "mixing nozzles", "plunger" and "applicator" are sold separately for an added $70 to the cost of the adhesive. Did you find these neccessary for your patch or was cutting open the contents and mixing the total of two parts on a palate with a putty knife application suitable? I will not want to store and keep these added tools if they are not needed for a one time application. What do you think? Take care and joy, Aythya crew


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## DulceSuerna (May 19, 2010)

4 weeks ago we had a massive water leak in our RV. I removed the water tank and found where the outlet hole is had been broken 3/4 of the way around. I cleaned it and used 5200. I put 4 layers (about 1 every 2 hours), into and around the crack. Ended up buildlng it up almost 3/4" I also put a few globs here and there just to check the adhesive(ness) is that a word? lol, of the 5200 and it seemed to Hold Great! filled w 40 gallons and it is still nice and dry. Not sure if your crack is due to load or? or even if the 5200 would work, Our crack was due to someone setting something on top of the outlet nozzle.


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## T37Chef (Oct 9, 2006)

brak said:


> I used Maritime Plastics of Annapolis - they built a tank for me. They do welding and seem to be able to create pretty much anything out of plastic.
> 
> Not sure if they can "come to you" but they would certainly be able to do the job if you can bring a tank (or, may be, recommend someone who can do it on site).


Thanks, will give em a call. I am able to get the tank out so I am hopeful. I priced a new one, $800.00


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## deniseO30 (Nov 27, 2006)

CaptainForce said:


> With the product description and reviews for 3M DP8005 Acrylic Adhesive, I'm going to attempt it for my repair. I notice that the "mixing nozzles", "plunger" and "applicator" are sold separately for an added $70 to the cost of the adhesive. Did you find these neccessary for your patch or was cutting open the contents and mixing the total of two parts on a palate with a putty knife application suitable? I will not want to store and keep these added tools if they are not needed for a one time application. What do you think? Take care and joy, Aythya crew


My son did the job actually but I think the mixing tubes worked fine Yes the cost of the dispenser holder has to be added. The big question is how accessible is your tank. To remove the tank out of the bunk in my O30 would have meant major "surgery" so we opted for a hole saw in the bunk side to allow access to the crack. I was totally amazed how well the compound works. It stinks to high heavens though. until cured.


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## CaptainForce (Jan 1, 2006)

deniseO30 said:


> ............The big question is how accessible is your tank...........


Actually this is not my big question, -everyone has their own complexities aboard. If I lean over my generator and tuck my shoulders in the space where I removed my exhaust fan duct, I can see the crack at the tank fill 8" from my nose. With my reading glasses and my hands tucked up as someone would mimic a Tyrannosaurous rex, I can tend the spot. I have patched this spot before using DulceSuerna's 5200 plan. It was marginally successful for many years, but left a drip when full or heeling. I pulled this old patch off with hopes of something better. I think my big question is time. I can't manipulate an applicator well in the space I have available; however, if I could thouroughly mix the two parts and have at least five minutes to apply it with a putty knife, I could have success. I can blow in air from an overhead cockpit locker so no one would find an asphixiated near-sighted T rex in my engine room.

Does anybody no how long it takes for this material to set-up? Take care and joy, Aythya crew


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## Michael K (Feb 27, 2006)

T37Chef said:


> Anyone have a recommendation for a "welder" in the Maryland area? My port side water tank has a small crack, just enough to be annoying.


Chesaapeake plastics in Eastport might be able to help.


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## arf145 (Jul 25, 2007)

deniseO30 said:


> every time this question comes up I give this information and no one seems to believe it works when I say it does. We used it on the poly water tank 3 yrs ago and it's still holding well. the repair was to a stress crack on the tank also.
> 
> 3M Scotch-Weld DP8005 Acrylic Adhesive


Hey, I'm filing that away for future reference, Denise. Thanks! Have a poly tank, don't have a crack now but could easily have one in my future.


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## brak (Jan 5, 2007)

T37Chef said:


> Thanks, will give em a call. I am able to get the tank out so I am hopeful. I priced a new one, $800.00


They actually built a large holding tank for me - price was $475 I believe which is relatively cheap considering that I saw quotes upwards of $1000.


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## deniseO30 (Nov 27, 2006)

it cures in a few minutes total cure in hours. oh the mixing nozzle works well too!


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## Allyn Salomon (Aug 28, 2020)

GaryHLucas said:


> I am in NJ but we do a lot of work in Maryland and I have access to a plastic welder. Not too likely the tanks are polypropylene, most are polyethylene. Polypropylene welds much better. I just welded 2 8" and two 12" vent pipes into 4 12,000 gallon polyethylene waste water tanks in Northeast Maryland. If you are north of Baltimore or so I could probably stop by in the spring and take a crack at it. We have had so so luck with tank repairs though. Sometimes it works, sometimes it don't.
> 
> Gary H. Lucas


I have a diesel 30 gallon tank with a 3"small crack. that was leaking fuel into the bilge. Have removed it from my boat and soap and watered out the film of diesel and sediment. I could transport it to you if you have the equipment to hotweld it. I am in Long Island.


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## pdqaltair (Nov 14, 2008)

Once a plastic tank has been in petroleum service, the oils permeate the plastic to some extent, and no repair, including welding, will be fully reliable. You need a new tank.

(decades of refinery work--repairs to polymer petroleum piping generally require complete rip-out to the nearest mechanical joint)


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## Minnewaska (Feb 21, 2010)

Give these folks a call. I had a very good experience with them. Sounds like it may not be repairable, but see what they say. They could certainly make you an exact replacement.









Triple 'M' Plastics


Foremost in Fabrication since 1972



triplemplastics.us


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## arf145 (Jul 25, 2007)

Allyn Salomon said:


> I have a diesel 30 gallon tank with a 3"small crack. that was leaking fuel into the bilge. Have removed it from my boat and soap and watered out the film of diesel and sediment. I could transport it to you if you have the equipment to hotweld it. I am in Long Island.


Definitely a nice offer! But note that this thread and that post are from 10 years ago, so...


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## Minnewaska (Feb 21, 2010)

arf145 said:


> Definitely a nice offer! But note that this thread and that post are from 10 years ago, so...


Funny, thought they were looking to fix it. Misread.


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