Fresh water tank material and leak

[crispyboy]

I was filling the fresh water tank before our last outing and noticed there was water dripping from the fresh water tank pan.
Last week I had an opening in my schedule to drop the fresh water tank pan and remove the tank. I filled the tank and found an inch long crack near the top of the tank. So now a repair is in order. I can go two ways to fix this leak. Repair the tank or buy a new one. I have not called to see of a new replacement tank is available. I'm sure a custom one could be found.

First I want to see if the tank is repairable. I would like to plastic weld it.
Does anybody know what the fresh water tank is manufactured from? I am thinking it is polyethylene. The trailer is from a 1994 Excella.
Whats your guess?
- polyethylene
- polypropylene
- ABS

[Belegedhel]

Hdpe, polypropylene. My best advice is to spin-weld a blank patch over the crack. Plastic welding might work also, but I did than any such welding I’ve done is not very reliable. There are other threads on this topic that recommend specialty glues, but there isn’t much that sticks to hdpe. End of the day, any fix you do is temporary until the next crack firms in that 50 yr old tank. Maybe cut your losses and just replace it. In a plastics might still have the exact mold you need.

[uncle_bob]

Hi

One very minor correction HDPE = High Density PolyEthylene (indeed nothing much sticks to it).

Bob

[crispyboy]

Just checked and the tank is available for $230 plus another $108 to ship - WOW!
Mulling my options....

[perryg114]

I think harbor freight has a plastic welder. It can be welded but not patched unless the patch is melted into the surface. If a tank it only $230, I would spring for a new one. It is most likely made of HDPE High Density Polyethylene.



Perry

[ROBERT CROSS]

Originally Posted by crispyboy

Just checked and the tank is available for $230 plus another $108 to ship - WOW!
Mulling my options....

Go for it...you can believe what was said above...not much will stick to it...especially a DIY fix, AMHIK. 🥴

Bob
🇺🇸

[ALUMINUMINUM]

Best thing might be a fresh new tank. Figure out why it cracked, and relieve that stress. The stress may be bouncing, twist, over-tightened, loose…??


If you'd like to try welding polyethylene, you might be successful as I was first try. I'd never welded plastic, but can MIG, TIG, Gas, and Arc. I found it quite simple, and most similar to gas welding and brazing.


You shouldn't use an open flame, that's why the plastic welding kits use hot air. Some folks have fashioned funnels for their heat-guns. Alternately to blowing hot air at the crack, use your 140W Weller soldering gun. V-notch/bevel the crack as you would for most any type of weld. Don't touch the plastic, just get the hot tip close enough to start your puddle, then feed it with your polyethylene rod. The nearest supply of perfect welding rod will be a cut off sliver of the tank's fill nipple or vent.


That's how this hillbilly welded the 3” crack around the outlet nipple of his 68GT's freshwater tank.. The repair has held for eight years so far.


A fun thing to learn… Didn't cost a dime… Did it in No Time...


Can't hurt to try before you buy a tank.

[GMFL]

I replaced mine. And here what it cost me straight for Airstream through local dealer.

[ALUMINUMINUM]

I got curious, checked the www, and discovered that there are polyethylene glue-stix for glue-guns. So, there's an avenue to explore. Might be good for a patch.


https://www.hotmelt.com/blogs/blog/g...ot-melt-sticks

Loctite makes a specialty glue.

A new tank would work too.

Also, PE Fumes are toxic, so beware ...

[Belegedhel]

Originally Posted by Belegedhel

Hdpe, polypropylene. My best advice is to spin-weld a blank patch over the crack. Plastic welding might work also, but I did than any such welding I’ve done is not very reliable. There are other threads on this topic that recommend specialty glues, but there isn’t much that sticks to hdpe. End of the day, any fix you do is temporary until the next crack firms in that 50 yr old tank. Maybe cut your losses and just replace it. In a plastics might still have the exact mold you need.

Gads... Me talk pretty someday. Frickin' auto-correct and tiny keyboard!

Anyway, I think a new tank would afford you a lot of peace of mind. Nothing lasts forever, and this old tank has had a good run, assuming it is the original.

Also, the supplier I tried to recommed was INCA Plastics. They might be able to provide an OEM shaped tank, as they were likely the original supplier.

good luck!

[crispyboy]

The name on the side of the tank is Shirlon. I tried a net search and only came up with a suspicious Chinese website......
GMFL you must have known somebody or just had a lucky day to get a tank that cheap. I have perused some of the aftermarket sites for a tank and they seem to be more expensive than Airstream.
I have one vacation day left this year and I live about 100 miles one way from Jackson Center. I am thinking about taking a ride since gas prices are down.