There is a small leak from our black tank where the sewer outlet is "supposed" to be joined to the tank. It looks like whatever process was supposed to join the tank to the sewer pipe just didn't take on a portion of the circumference. I want to avoid replacing the tank or taking the trailer to have it "plastic welded". I would like to try:3M™ Scotch-Weld™ High Performance Industrial Plastic Adhesive 4693H. I would clean up the area I think is leaking with sandpaper and just apply the adhesive. I would appreciate your thoughts.The picture is taken from below:The tank is in a 2008 Keystone Cougar 276RLS 5th Wheel trailer. The tank has a label on it that reads:Ameri-Kart CorpR.V.Model 515File No. LM33087Std. No. B45.6I assume the tank is polyethylene and I am not sure what the material is that it is partially bound to. Perhaps ABS?Thanks,danglo

sounds like a plan. try just a dap before you glue the hole thing, ake sure your glue doesn,t eat the plastic. and double check its not the bolted area leaking.

midnightsadie wrote:sounds like a plan. try just a dap before you glue the hole thing, ake sure your glue doesn,t eat the plastic. and double check its not the bolted area leaking.Thanks. I got a pretty good look at the area (with a light and mirror). The only apparent leak is at the radius formed where the tank joins the horizontal sewer connection, not the valve.danglo

We had this same problem fixed by Camping World. They actually put two entire tubes of silicone caulking around the place where the pipe enters the tank. Then after three days tested by filling the tank until it filled the toilet pipe. No leak. We have decided one way to stop the leak is not to let the tank get 100% full. Seems to have held so far.

BOTTS 12 sounds like a CW repair more is better ,it only takes a little silicone in the right spot to stop a leak . I,d rather take the joint a part and re glue ,but you gotta see it to judge it.

You may want to see if TAP Plastic's PolyWeld will help you out. I got great results in a black tank repair from it although it is a little more complicated to use. While I was down in the area, I also used Rustoelums Black Stop Leak spray to clean up the job visually -- and reinforce the job.

Another black tank leak repair question | Good Sam Community

18 Replies

danglo
Explorer
Aug 12, 2013
I just noticed that Eternabond information states that it sticks to polyethylene.

Has anyone ever used Eternabond to repair a leak in a polyethylene black tank?

If it would work, I would use a strip about 1/2 inch wide and as long as it takes to go around the 4" (apx.) joint, then if that sticks , maybe top that with a wider strip.

I know, it will be hard to make the eternabond go around that 4 inch circle. Any hints to make it easier?

Thanks everyone,

danglo
Handbasket
Explorer
Aug 12, 2013
I had a tiny, tiny leak in the black tank plumbing on the Tiger during the 1st year from new, at about where yours is. Since it's really simple, accessible plumbing, I chose to pursue a 'look into it' strategy before taking it to a shop for a warranty repair. It turned out to be simple. There's a female-threaded plastic bushing that I think is spin-welded into the tank. The end of the big pipe leading out to the valve is male threaded. I had black 'water' following the spiral leak path around that threaded joint. A thin coat of Teflon pipe dope paste cured it completely, and has held for 7 years.

Jim, "There are worse things than a wrong number call at 4 AM. It could be a right number."
danglo
Explorer
Aug 12, 2013
After talking to the manufacturer (Ameri-Kart Corp) I believe the tank to be Polyethylene, NOT ABS.

As you may be able to see in the picture, the leak is along a seam. I know I can order a holding tank kit that requires preparing the surface with a propane torch to change the chemistry of the plastic, allowing a special plastic to adhere. I have some concern about using a propane torch in a tight place.

The 3M 4693H glue which is advertised for use on polyethelene may not require that pre-heating. Has anyone used the 3M 4693H glue on polyethylene?

Thanks,

danglo
time2roll
Nomad
Aug 12, 2013
Plastimend is part solvent part dissolved ABS plastic already in the correct ratio. I have read posts of adding ABS shavings to solvent adhesive to make your own soup with success. And I still think plasti-mend is superior and permanant.

I have used it just once after two different epoxy products failed. My leak was a crack 1.5" long starting in a corner where the ABS flexes during every fill or if bouncing down the road. I also added some sheet ABS as my tank seemed to be moulded very thin in that corner. I used a heat gun to shape the ABS sheet then attached with plasti-mend. That was several years ago. I doubt you need anything extra for repairing the ridged joint that you have leaking.
westend
Explorer
Aug 12, 2013
smkettner wrote:
Snowman9000 wrote:
Plasti-Mend!

Works as advertised. Also sold on Amazon, I see.

Amazon reviews of it

+1 for plasti-mend on ABS. I guaranty this is a permanent solution. You could make a whole new custom tank out of the stuff.

Do you think regular ABS solvent glue would do the job or is the Plastimend heads above?
time2roll
Nomad
Aug 12, 2013
Snowman9000 wrote:
Plasti-Mend!

Works as advertised. Also sold on Amazon, I see.

Amazon reviews of it

+1 for plasti-mend on ABS. I guaranty this is a permanent solution. You could make a whole new custom tank out of the stuff.
Snowman9000
Explorer
Aug 10, 2013
Plasti-Mend!

Works as advertised. Also sold on Amazon, I see.

Amazon reviews of it
Lon-Str
Explorer
Aug 10, 2013
My ten year old Montana developed a leak in the same place as pictured shortly after the warranty expired. After wire brushing and sanding the area with coarse sandpaper, I applied a coat of ABS cement around the area. After it had dried, I cut a one and one half inch strip of fiberglass cloth and after saturating it with cement, applied it all the way around the fitting. After it had dried I added a couple more coats.

That was many years and many, many miles ago, including two trips all over Canada and Alaska. It is still watertight today.
danglo
Explorer
Aug 10, 2013
Thanks all.

I have sent an email to the mfg. asking what the tank is made of and recommended repair chemicals.

I will post their response.

danglo
path1
Explorer
Aug 10, 2013
When I had a leak I used something like this stuff. Got it at Camping world (but could not find a link to it at CW web site before posting). I didn't think it would work but thought I would give it try. Several years now and no problem. NOTICE IN ADD that there is other stuff for different types of plastic. You need to get the type you need by the type of plastic you have. (Very important to have right stuff for your type of plastic). Mine was pretty easy to tell what type of plastic. Saw manufacture name stamped on tank, looked them up on google and called them and asked what type of plastic.
http://www.pplmotorhomes.com/parts/caulks-sealants/holding-tank-repair-kit.htm