Grey Water tank leakage

Thank you for the posts of past years on hairline cracks in the GW tank.
We incurred one now also.
I've used two layers of Medium Black ABS cement.
It did not truly fix the problem but helped somewhat.
My wife then told me she had purchased Flex tape.
I placed that on the crack, which is in the center of the rib in the middle of the tank, as well as by the out take. Yep, two leaks in one trip. No clue why.
Anyway, I read that one should drill a small (HOW SMALL?) hole at the start and a hole at the end of the crack. Would that not make the sepage worse if the cement or the flex tape do not fix the problem.
Also, I read about 'welding' the crack. What exactly is meant by 'welding.'

So, at the point in time I wonder if I should take off the flex tape AND scrape of the cement to the best of my ability and start over.

Any good suggestions from you who know more than I do on this, and I don't know too much, would be greatly appreciated.

Thank you so much.
John G.

BTW our trailer is a TM 2027 model year 2007. Its been around but works great.

You shouldn't need a large hole. Drilling a hole at both ends of a crack, is referred to as "stop drilling". I'll assume a size of the lead in yer standard #2 pencil would work. The intent is the holes, prevent the crack from growing longer. It's been awhile since I've read those other posts on repairs. I believe folks took shavings of black pvc and mixed it with the glue to make a patch.
Hope this helps some. Good luck.

One more minor correction on model: 2720SL

I had a crack 2/3 around the outlet pipe plus one in the middle rib of my gray tank. I used this plastic weld epoxy (bought from Home Depot but can’t find it on their site now), it worked mint. The whole saga about prep & repair is on the TrailManor Fans page over on Facebook, link below. Also I’m working on a support for the gray tank similar to what the Factory now puts on the new units (won’t fit the older units as they use a different tank these days). You’d be amazed how much the belly of that tank swells when full of water. A bit of support has to help there.

https://www.jbtools.com/permatex-84...MIptmc4Kmy-QIVdAaICR2bdgzFEAQYAyABEgIw6_D_BwE

https://www.facebook.com/groups/1694232044174756/permalink/2416144045316882/

Kidkraz said:

The ... holes prevent the crack from growing longer.

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If you visualize it in your mind, the stresses concentrate at the tiny bit of material at the very narrow end of the crack. These concentrated stresses cause the crack to propagate further. By drilling a hole, you open up that very narrow region - the stresses are not eliminated, but they are distributed.

Think of putting the blade of a table knife down between your fingers, edge first, pressing into the flesh. You don't need a lot of force for the edge to cut into your skin. Now think of turning the knife so the flat is pushing into the skin. You can apply the same amount of force as before, but because the force is distributed over a wider area, you don't get cut.

Bill

Shane, I just ordered the permatex plastic welder from JBTools online. Hefty shipping but rather pay that than getting a bigger mess with the GW tank. I'll post after having received it and worked on it. The pictures and description on FB were very helpful and made me purchase the permatex.
Bill, thank you for the illustration

John -

Hang onto that welder! Every once in a while, someone drops too much weight onto the Thetford toilet seat, and cracks the tank surface below it. Prevention is easy - repair, not so much. See

https://www.trailmanorowners.com/forum/showthread.php?t=10819

for some discussion and photos. Post #1 shows repair. Post #8 shows prevention.

Bill

Bill, should you read this, I have the following question. Per Shane's, suggestion, after having drilled pinholes (was able to use a 3/32 inch drill bit) should I get some PVC pipe (color does not matter, I'm sure) and then use the permatex welder, paste the pipe shavings and welder in the holes. Should I then wait for 24 hours before covering the cracks? Just wondering.

For the time being, I've tried to shave off the ABS 'glue' as much as possible by/on the crack and wonder if it would be good to 'sand' the area a bit, making it rougher so the weld may hold better?

John -

My apologies, I cannot answer your question. I have not experienced (or repaired) a leak in the plastic tank, and I have not used a plastic welder. Other folks here on the Forum have done both, and you can expect to hear from them.

Bill

The Permatex stuff is thick enough you can fill the holes with it.

I've never had a leak in that tank but I had a crack in my kayak once. I did the whole drill stop thing and welded it with this plastic welder. It is well worth the $. I've used it a number of times since.

https://www.harborfreight.com/plast...r-motor-and-temperature-adjustment-96712.html

I followed this video to repair a pretty good sized crack in my grey water tank... It held up well for about 2 years afterward before I sold the trailer.

https://youtu.be/N2rVLU3bDMY

Graywater tank leak repair

I have a 2003 2720SD that developed leaks along the longest inverted rib of the graywater tank. I found numerous cracks at the bottom of the longest V-channel that spans the 30 gal tank. The length of this section of cracked v-channel was about 16 inches. I speculate that numerous cycles of the tank bottom bulging under the weight of 25+ gallons of graywater would have the effect of spreading apart the walls of the "V", and over time causing stress cracks. I wanted to repair in place to avoid a lot of headaches.

Anyway, I found a youtube video from 2015 that showed good directions for RV tank repair. To find it, Google "trailerdayz repair youtube" and select the Aug 6, 2015 25:01 video. Note: I had used these directions twice before for repair to a hairline crack and to a thumb-sized hole (!) in the black ABS pipe on my TM back in July 2016. No leaks from those 2 repairs over 6 years ago!

I followed the video directions using homemade thick slurry from black AB pipe shavings plus black Medium ABS cement. (Drilling into ABS pipe works good to get the shavings--clamp the pipe securely and beware a sudden torque to drill when bit breaks through the pipe!) I laid down 2 patch layers with black fiberglass window screen material in each layer for more strength. I then continued adding more patch layers to fill up the inverted v channel and finished with 2 plain coats of ABS cement.

I filled up the entire length (about 40 inches) of that main v-channel rib. It is tedious work on your back in close quarters under the TM. Because you are applying thick layers to fill this channel, you want to give each patch layer plenty of dry time (a week or more) to get good and hard. I used a wood plane to shave down high spots near the end of the process, before finishing off with 2 layers of ABS cement. All told, I took about 5-6 weeks to finish it.
I am retired, 68 yrs old, in no hurry, lol!

To reduce future stress to the repair, i installed a 36 inch long, right-angle thick sheetmetal brace, running front to back (parallel to the TM length) under the center of the tank. I had to custom -make 2 very stiff metal braces that i attached to each side of the long brace, then bolt these to the even-thicker frame material above and near each end of the tank.

The repair withstood a 30 gallon fill to capacity, no leaks. I could see the 36-inch brace bowing under the pressure of that much water on the bottom of the tank, then it returned to straight after dumping the water. An I beam type brace would provide more support.

Traveling far with a nearly full tank, after boondocking and enroute to a dumpsite, may have been the straw that broke the camel's back, causing the cracks to advance toward leak stage. So for prevention, I will try to dump
ASAP in future trips!

Charlie

I used the same approach as Charlie on a leak on the flange of the gray water tank and had good results. No leaks so far. https://www.trailmanorowners.com/forum/showthread.php?t=20631

If I have a similar problem in the future, I'll try a product called Plast-Aid, which I wasn't aware of at the time. I've since used it to repair a 1/8" - 1/4" hole in a PVC sprinkler line that was in a location that would have been very difficult to cut out and replace the line. The mend has held for numerous months under the pressure of the sprinkler system. I've also successfully used it to repair a leak in an air mattress. The manufacturer claims it chemically fuses with PVC, ABS and acrylic. Good stuff.

As Charlie suggested, my approach now is to dump the gray water tank ASAP before transporting the TM.

A follow up on the 'leaking grey water tank.' I did purchase the Permatex 'plastic welder' and it worked absolutely fantastic. Since were not in a rush to use our TM I let the welder cure a few days.

Then my son and I did place a 2 inch wide metal strip below the grey water tank so it will not sag too much when the tank fills up. We used rivnuts in the beams on each side of the water tank to hold the bolts and it all seems very strong.

I do appreciate all who have spoken into this issue. So very helpful.

my son in law told me the other day he had a crack on his water tank and sprayed flex seal on the crack, never leaked again, that's been a year ago,,kinda wondering about this

peanutmydog said:

my son in law told me the other day he had a crack on his water tank and sprayed flex seal on the crack, never leaked again, that's been a year ago,,kinda wondering about this

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I'm not sure what you mean by "Water tank". If you are talking about the fresh water tank........ that tank is made of polypropylene. NOTHING...... and I mean NOTHING will truly adhere to polypropylene except polypropylene welding with a good plastic welding machine and polypropylene welding rod.

If you are referring to the waste water tank.......... That tank is made of ABS plastic. It can also be "welded" but it is essentially a "chemical weld".

I have done extensive chemical welds on my current TrailManor Elkmont black water tank and I posted pictures and the procedure on this forum. You should be able to find that post (quite long and detailed) with a search of "tank repair" and my name "Wavery".

To answer your question about drilling holes at each end of the crack........ When a crack happens in plastic (indeed most materials), the crack will get progressively worse as the crack weakens the material at the end of the crack until that material separates, continuing the crack. When you drill a small hole (usually 1/8") just at either end of the crack, you remove the weakened material, thus ending the progression of the failure. Then when you "weld" over that area, the crack and holes are all filled to sound material.

Here is a good video

wavery said:

NOTHING...... and I mean NOTHING will truly adhere to polypropylene except polypropylene welding with a good plastic welding machine and polypropylene welding rod.

Click to expand...

Wavery -

Loctite offers a relatively new product called Loctite Plastic Bonding System, available at Ace Hardware, etc, at reasonably low cost. It is a 2-part cyanoacrylate glue that specifically includes polyethylene and polypropylene in its list of will-glue plastics. I have not used it, so I don't know how strong or flexy the bond is, or if it would be appropriate here. But it would be easy to try. I would like to get reports from anyone who has tried it for any purpose.

Bill