Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 10-29-2019, 10:16 AM   #1
2014 Heritage Glen
 
Join Date: Feb 2016
Posts: 24
Repairing Polyethylene Fresh Water Tank

My Forest River 35' Heritage Glen developed a water leak under the TT. I have, at times, filled the 30 gallon tank before I traveled. I found the leak was coming from the polyethylene fresh water tank itself. Further investigation showed the metal bracket that supported the rear of the tank was bent and the tank had dropped down about an inch in the front. When this happened, the tank slid forward and the tank rubbed up against another front bracket that caused a small crack in the front, on each side of the tank. I plan to repair the tank using the polyethylene/heat method. I have a heat gun and have ordered the polyethylene strips to repair the cracks. In the meantime, I read where a plastic milk jug is made of the same polyethylene plastic and the jugs have HDPE (High Density Polyethylene) stamped on them. Is it OK to use the plastic from the jug to repair the cracks? I also plan to reinforce the supports around the tank to fully provide the proper bracing for the tank which it did not have. Needless to say, the 30 gallon tank will be empty from now on anytime the trailer is towed!
Rwgrigg is offline   Reply With Quote
Old 10-29-2019, 10:43 AM   #2
Senior Member
 
SeaDog's Avatar
 
Join Date: Jan 2016
Location: x
Posts: 12,423
I have not tried to repair a crack in a tank and do not know about milk jugs. However I have repaired the supports for potable water tanks and if done correctly there is no reason for not caring water in your tank other then the added weight.
__________________
Retired Navy
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho
SeaDog is offline   Reply With Quote
Old 10-29-2019, 11:11 AM   #3
2014 Heritage Glen
 
Join Date: Feb 2016
Posts: 24
Quote:
Originally Posted by SeaDog View Post
I have not tried to repair a crack in a tank and do not know about milk jugs. However I have repaired the supports for potable water tanks and if done correctly there is no reason for not caring water in your tank other then the added weight.
Thanks, Sea Dog I've seen on other post where 2" X 2" X 1/4" angle iron was used to reinforce the support with good results.
Rwgrigg is offline   Reply With Quote
Old 10-29-2019, 11:36 AM   #4
Pickin', Campin', Mason
 
5picker's Avatar
 
Join Date: Aug 2015
Location: South Western PA
Posts: 19,074
If you have the 'proper' stuff on order, I would not try to patch with a milk jug that you don't know the composition of the material. Why not just wait for the right stuff to arrive?
__________________
2022 Cedar Creek 345IK 5th Wheel•Solar & Inverter•2017 Ford F-Series SCREW 4x4•Factory Puck•B&W Companion•TST Tire Monitor w/Repeater•Sinemate 3500w Gen.
F&AM Lodge 358 Somerset, PA - JAFFA Shrine - Altoona, PA

Days Camped '19=118 '20=116 '21=123 '22=134 '23=118 '24=86
5picker is offline   Reply With Quote
Old 10-29-2019, 12:00 PM   #5
Senior Member
 
bob213's Avatar
 
Join Date: Apr 2012
Posts: 1,472
You could try this if you have room to get the heat gun near the crack.
https://www.tapplastics.com/product/...d_adhesive/435
__________________
You can avoid reality, but you cannot avoid the consequences of avoiding reality – Ayn Rand
bob213 is offline   Reply With Quote
Old 10-29-2019, 04:13 PM   #6
Senior Member
 
Join Date: Apr 2017
Location: 8300 Feet - Rocky Mountains
Posts: 2,441
My 2 cents...perhaps all it's worth.

If you attempt repair, expect disappointment. You might get lucky, but more likely not. A plastic weld might work...as might the TapPlastics product. Don't mess with a milk jug. You'll probably only get one chance at a "weld." And the work involved with doing the job, putting it all back together, adding more bracing, and then discovering failure is not worth a milk jug experiment. I understand that there are pros who do plastic welds.

After many attempts to patch or seal my tank, I surrendered and installed a new one. The crack just kept growing, and no adhesive really stuck. My replacement tank cost about $95 plus about $20 for shipping...from Forest River. I was thrilled with the price. Yours might be $200 + $35 shipping.

If you intend to replace, first verify that tank removal and replacement is reasonably possible. Inspect carefully and measure clearances. In my case, the tank sits somewhat over the torsion axle. And the cable roof lift mechanism passes below the tank but over the axle. If I had not lifted the camper, I would have had to drop the axle to get it out. Removing the cable lift is, at least with my skills, out of the question. Since I was lifted, I had just barely enough room to remove and replace. Dropping the axle would have been very hard. As it was, the job was easy.

Above all, repaired or replaced, substantially reinforce your tank supports. If it's tucked up out of harm's way, angle iron or U-channel will work wonders. But it's likely you'll need to be inventive installing the bracing...and careful to avoid puncturing the tank or wiring or propane lines, etc. You may need to fabricate hanger straps for your additional bracing.

The good news (if you can call it that) is that your tank is empty and the supports require attention anyway. Plan your attack and use the opportunity to move the tank out of the way to attach mounts for your additional bracing. Any fasteners that might touch the tank should be padded to prevent them from wearing thru the tank. Elevator bolts might be handy here: https://www.amazon.com/Hard-Find-Fas...56056391&psc=1 My tank was shouldered with wood blocking to keep it from chaffing on steel, but every one is different.

In my PUP, I got very lucky. There are "looms" for propane lines, wiring, etc. on either side of the frame, so a piece of 1/2" galvanized water pipe, a pipe clamp, two clevis pins, a square of plywood and a rubber door mat did the trick. My tank's only 20 gallons, so the support isn't doing that much work, but before I installed it, my tank was sagging about 4". Now no sag at all.

I boondock exclusively so I always travel with a full fresh tank, and I normally travel extremely rough gravel roads and sometimes no roads. The support made all the difference. You need to find a way to achieve the same goal if you intend to boondock or travel wet to a location that doesn't have potable water.

The 2nd pic is my idea of camping.
Attached Thumbnails
Click image for larger version

Name:	Fresh Water Support.jpg
Views:	119
Size:	51.2 KB
ID:	218308   Click image for larger version

Name:	a-lost park1.jpg
Views:	110
Size:	574.2 KB
ID:	218309  
__________________
Jim & Renee
2020 Jayco Jay Feather X-213
previously 2014 Forest River/Rockwood HW 277
2006 Ram 1500 4WD Crew with Firestone Airbags
Every weekend boondocking in the National Forests or at Lake Vallecito.
jimmoore13 is offline   Reply With Quote
Old 10-29-2019, 04:40 PM   #7
Senior Member
 
Brother Les's Avatar
 
Join Date: Jul 2013
Location: BoCoMo
Posts: 2,784
imo, fix your supports to hold the correct (over) weight, then get a new tank.

The plastic water jug will not be compatible.
__________________
Brother Les

2013 Forest River Salem Hemisphere SBT312QBUD

2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler
Brother Les is offline   Reply With Quote
Old 10-29-2019, 05:40 PM   #8
Senior Member
 
Swampy's Avatar
 
Join Date: Dec 2015
Posts: 241
Quote:
Originally Posted by Rwgrigg View Post
My Forest River 35' Heritage Glen developed a water leak under the TT. I have, at times, filled the 30 gallon tank before I traveled. I found the leak was coming from the polyethylene fresh water tank itself. Further investigation showed the metal bracket that supported the rear of the tank was bent and the tank had dropped down about an inch in the front. When this happened, the tank slid forward and the tank rubbed up against another front bracket that caused a small crack in the front, on each side of the tank. I plan to repair the tank using the polyethylene/heat method. I have a heat gun and have ordered the polyethylene strips to repair the cracks. In the meantime, I read where a plastic milk jug is made of the same polyethylene plastic and the jugs have HDPE (High Density Polyethylene) stamped on them. Is it OK to use the plastic from the jug to repair the cracks? I also plan to reinforce the supports around the tank to fully provide the proper bracing for the tank which it did not have. Needless to say, the 30 gallon tank will be empty from now on anytime the trailer is towed!
Rwgrigg, I think your approach is good, but you may need a plastic welding tool to make this work. You may be able to gather enough heat from a heat gun, but the wind from the gun may make handling the liquefied plastic impossible. Prior to retirement, I have installed miles of HDPE electrical conduit and I promise you there is no adhesive made that can chemically weld the two sides together. Those that are advertised are really a type of epoxy that only sticks to the surface once it is roughed up enough to provide some grip surface area and in a wet environment, they always fail. The only appropriate method to join HDPE conduit is via thermal fusion. This requires getting the plastic very hot ( I think it was somewhere around 350 to 400 degrees F) it must liquefy before the 2 edges are mated together. If you can do this, the crack should be repairable and the repair will be permanent. Before you return the tank to the underbelly, be sure to have some substantial bracing ready to install. You also want to provide some padding between any bracing and the tank since it seems to fit somewhat loosely and is subject to moving about ... enough to rub.
If you end up not being able to seal the leak, then I suppose replacement may be your only option. Again I would prepare additional bracing and padding before I install it. Good Luck with the project! ... Jim
__________________
Jim (Swampy), Susie, Jimmy & The Chihuahua Crew
2008 Chevy Silverado LS, 4.3L, V6, 2WD, 3.23:1

2014 287 BHBE; 1981 JayRaven: Predator 3500i - Call Home Pearl River, Louisiana. on The Honey Island Swamp
https://www.forestriverforums.com/at...pic81807_1.gif
Swampy is offline   Reply With Quote
Old 10-29-2019, 07:31 PM   #9
Member
 
Join Date: Sep 2016
Posts: 89
Also before welding the crack drill a small 1/16 hole at the start of the the crack at each end of the crack. This will stop the crack from spreading after welding it.
kurtsont is offline   Reply With Quote
Old 10-29-2019, 07:53 PM   #10
Senior Member
 
Bluepill's Avatar
 
Join Date: Jun 2015
Location: Pensacola, FL
Posts: 1,645
You might want to get a few small pieces of poly to practice on before making the tank repair. Like all fusion work (Soldering, brazing, welding, etc.) experience is your friend.
__________________
2019 Coachmen Freedom Express 192RBS
2015 T12RBST Flagstaff Hardside

Disclaimer: The actual value of my "Two Cents" of advice varies just like a bitcoin.
Bluepill is offline   Reply With Quote
Old 10-29-2019, 08:36 PM   #11
2014 Heritage Glen
 
Join Date: Feb 2016
Posts: 24
Anybody know if the TAP Poly-Weld adhesive really works on polyethylene? https://www.tapplastics.com/product/...d_adhesive/435

How about Marine Tex Flex Set?
Marine-Tex® FlexSet | Marine Tex
Rwgrigg is offline   Reply With Quote
Old 10-29-2019, 10:40 PM   #12
Senior Member
 
Swampy's Avatar
 
Join Date: Dec 2015
Posts: 241
Quote:
Originally Posted by Rwgrigg View Post
Anybody know if the TAP Poly-Weld adhesive really works on polyethylene? https://www.tapplastics.com/product/...d_adhesive/435

How about Marine Tex Flex Set?
Marine-Tex® FlexSet | Marine Tex

These products are basically an expensive 2-part epoxy. In my experience, they all fail because nothing actually sticks to polyethylene. You can slather it on like paint, but it will not bond to the PE and ultimately it will pop off. As I stated in an earlier post, the only sure fire way to get polyethylene to stick together is via thermal fusion where you melt the PE and let the molecules of each part merge together. Normally the resultant joint is stronger than the original. Using the fusion method of joining PE conduits, I have made horizontal pulls in a bore hole of over 1000 feet. Dresser couplings usually failed in under 100 feet, and Bonduit and several other brands I have tried usually came apart at less than 100 feet. You neede to read the product specifications as well as the application data.... Swampy
__________________
Jim (Swampy), Susie, Jimmy & The Chihuahua Crew
2008 Chevy Silverado LS, 4.3L, V6, 2WD, 3.23:1

2014 287 BHBE; 1981 JayRaven: Predator 3500i - Call Home Pearl River, Louisiana. on The Honey Island Swamp
https://www.forestriverforums.com/at...pic81807_1.gif
Swampy is offline   Reply With Quote
Old 10-30-2019, 08:32 AM   #13
Senior Member
 
Join Date: Aug 2019
Posts: 106
Quote:
Originally Posted by Swampy View Post
Rwgrigg, I think your approach is good, but you may need a plastic welding tool to make this work. You may be able to gather enough heat from a heat gun, but the wind from the gun may make handling the liquefied plastic impossible.



I agree with getting a true plastic welder (A decent one and not one from Hazard Fraught).

Trying to use a heat gun, even if you have a plastic welding tip for it, is a crapshoot. The wall of a FW tank is thin, less than 1/8" usually, and you stand a good chance of blowing a hole clear through it. A good tool that you have full control of the heat is important. So is practice. Buy some cheap cutting boards and poly bins at Walmart and practice on those first.

Its a lot harder to weld thin material than thick, it's way less forgiving. Also doing it upside down is tough. It's a lot easier if you can get the tank out and are welding down on it, such as on a bench.

They have cutting boards at Wallyworld that are compatible and are about 3/8" thick. I have cut those into squares larger than a crack if its not on an edge and welded them over it . Stronger and easier than trying to stitch the crack closed with the thin wall.
Feel Swift is offline   Reply With Quote
Reply

Tags
fresh water, repair, tank, water, water tank

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 09:21 AM.