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Replacement RV fresh water tank

Otto M@n

Otto M@n

Red Skull Member
Joined
Jan 1, 2022
Member Number
4654
Messages
18
TL;DR: Years ago broke a leaf spring on my bumper pull toy hauler. Axle swung back, hitting the 110 gallon fresh water tank that sits above and in between the tandem axles, causing several cracks.

My original fuck up was not just plastic welding it properly from the get-go using the right filler material. Since the bottom of the tank isn't supported, I can get it to stop leaking, but then it leaks again when it's filled with water and flexes during driving. I've emailed forest river (Work and Play toy hauler) and waiting a response, but is there any way of identifying what type of plastic the tank is? I assume it's stamped, but it's probably on top of the fucking tank that I can't see unless I remove both axles and drop it entirely, which at that point, I'd just put a new tank in and not fuck with trying to patch it. :homer:

If anyone knows of RV junk yards in the Maryland area, I wouldn't even be opposed to putting in a 50 or 75 gallon size replacement. I only have a 35 gal black and gray tank, and never camp for more than 3 nights anyways, so 110 gallons is overkill anyways.

I tried the plastic welder kit from Harbor Freight and this one, but both kinda suck at welding a thick plastic tank like this fresh water tank. I've seen some people use a soldering gun as it has more wattage to try and get better heat penetration into the plastic. Looking at it now, I should have got the 200 watt one and not the 110 watt one. Oh well.

 
I bought an aftermarket tank to add to my RV, it was HDPE.
If if you repair yours with a plastic welder, it will probably fail again there because of the flexing you said, build a cradle for it.

My friend cracked their tank while out and we flex seal taped it. I didn't think that stuff stuck to HDPE, but it's been leak free for 2 or 3 years.
 
just get the dimensions and buy another online??


Is it one tank or two?
I have 100 gal, and after five years of using it , I realized that the valve to the back tank wasn't even open:laughing:
 
Otto M@n said:
TL;DR: Years ago broke a leaf spring on my bumper pull toy hauler. Axle swung back, hitting the 110 gallon fresh water tank that sits above and in between the tandem axles, causing several cracks.

My original fuck up was not just plastic welding it properly from the get-go using the right filler material. Since the bottom of the tank isn't supported, I can get it to stop leaking, but then it leaks again when it's filled with water and flexes during driving. I've emailed forest river (Work and Play toy hauler) and waiting a response, but is there any way of identifying what type of plastic the tank is? I assume it's stamped, but it's probably on top of the fucking tank that I can't see unless I remove both axles and drop it entirely, which at that point, I'd just put a new tank in and not fuck with trying to patch it. :homer:

If anyone knows of RV junk yards in the Maryland area, I wouldn't even be opposed to putting in a 50 or 75 gallon size replacement. I only have a 35 gal black and gray tank, and never camp for more than 3 nights anyways, so 110 gallons is overkill anyways.

I tried the plastic welder kit from Harbor Freight and this one, but both kinda suck at welding a thick plastic tank like this fresh water tank. I've seen some people use a soldering gun as it has more wattage to try and get better heat penetration into the plastic. Looking at it now, I should have got the 200 watt one and not the 110 watt one. Oh well.

Click to expand...
My wild ass guess is that it's HDPE-2 just like kayaks and many food grade containers.

You can melt and remelt it indefinetly. No need for any fancy shit "plastic welding" gun. Just get an old flat screwdriver and a propane torch and heat it up. V out the cracks, then smoosh new hot plastic into the V.

For my red kayak I cut up a Folgers coffee can for strips of plastic.

You can also heat up big patches of plastic in the oven on a piece of aluminum foil, then preheat your tank and slap the patch on.
 
It's not going to be stamped.

Order a new one via dimensions.

Source: me buying and building 2 buses and a box van tiny home.
 
Muckin_Slusher said:
My wild ass guess is that it's HDPE-2 just like kayaks and many food grade containers.

You can melt and remelt it indefinetly. No need for any fancy shit "plastic welding" gun. Just get an old flat screwdriver and a propane torch and heat it up. V out the cracks, then smoosh new hot plastic into the V.

For my red kayak I cut up a Folgers coffee can for strips of plastic.

You can also heat up big patches of plastic in the oven on a piece of aluminum foil, then preheat your tank and slap the patch on.
Click to expand...

So this was the biggest help. I got fed up with the shitty, "cold" effect of the plastic welder. I got so mad that I got my mapp torch out and heated that MF'r up so hot it started to turn clear and toyed with it until it was juuuussssttttt beginning to lose its original shape because it wanted to start to droop :laughing:

But what that did do was help melt the cracks back together. By preheating the area with the torch, it made the welder work MUCH faster and easier. Also, Google said you can use LDPE rods on HDPE but not vice versa. I got some HDPE rods and noticed it worked much better...has to be a HDPE tank.

And when the welder melts the HDPE filler, it "wicks" the plastic into the tank. There was definitely a learning curve to see how the plastic melts together once it's actually hot, instead of just melting some plastic on top of the base that's too cold to properly fuse together.

There were two very minor leaks after I put water in it, but to be fair, it was a fucking mess because of all the other shit I've tried. JB Weld, plastic JB weld, flex seal...lots of contaminants. I used my whizzer wheel with the scotch brite pads and cleaned off as much shit as I could.

Lesson learned. From the first time it cracked, I shouldn't have tried to patch it with anything else. This would have been 100x easier on a "fresh break" without the other crap on it. Whatever...lesson learned. All I know is that I don't have to drop/replace that fucking tank :beer:
 
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