Have any of you used a Flex Seal product to repair a crack in a holding tank?

Unfortunately I gave it a try on other projects around the house....my opinion: junk and hype.Might look at something like JB Weld for the repair on your grey tank..Good luck with it.

Unless it is a replica of the San Andreas fault, GOOP adhesive is as good a repair as any. The crack need to be dry. Place the nozzle of the tube hard against the crack, squeeze then follow the crack. Repairs have outlived my ability to keep track of them years later.This stuff stretches like a rubber band and adheres tighter than a Time Share salesman. Scuffing up the edge area alongside the crack with 80 grit makes it stick even tighter. Want decorative results? Paint over top with RustOLeum black bed paint.

Not on a grey tank but I've had to use it on my shower stall floor.It held up fine for the last 2-1/2 years we had the camper. The tape is very similar to eternabond. I had to use it in a pinch and was surprised at its durability.I drilled a 1/8" hole at each end of the crack then cleaned/prepped the floor with naphtha then cut a piece of flex seal a few inches to overlap the crack and it held up great. Very sticky to work with if you handle it a lot. I used the flex seal paint over the tape to blend the tape in with the bottom of the stall. Stuff worked good also. "As seen on TV" product made me squirm a little, but, it worked well.Good luck,Rick

I've used goop on everything from my slide seal to shoes to motorcycle seats. Most of the time it's sold out at HD near me. 600 is often sold as a fabric mender and seems similar to goop. If the tank is black abs I've also repaired with a kit found online. People use abs shavings and mixes that you can find on YouTubeGoops contribution to mankind is right in there with weedeaters, bungee cords and chainsaws.

We used on a crack in the tank of our commode in our S&B several years ago. We put 3 coats on it, letting it dry the recommended time specified. It lasted for about 2 years before it began leaking again. I wanted to dry, spray and let it work for another two years, but DH decided he would rather just get a new commode.

Flex Seal repair on grey tank. | Good Sam Community

29 Replies

map40
Explorer
Sep 15, 2018
1 or 5 minutes epoxy with fiberglass polyester cloth. Epoxy layer, polyester layer, epoxy layer, polyester layer, epoxy layer. Loctite epoxy will remain semi-flexible. It will never come off
Ralph_Cramden
Explorer II
Sep 14, 2018
LarryJM wrote:
Ralph Cramden wrote:
Just because its colored black means nothing. Alpha Systems tanks are on many RVs. Theyre black and are not ABS, they're HDPE.

ALPHA SYSTEMS

It's really easy to determine ... just wet the tank with Acetone and if it becomes sticky its ABS unless some other material dissolves like ABS to Acetone.

Larry

Even easier is to look at the connection where the 3" abs pipe connect to the tank. If its glued its abs, if its mechanically connected with a clamp, its probably HDPE.

Or look at the flange on the top where the tank hangs on the spreaders. If its flat and around 1/4" thick its abs. If its about 1" thick and is blow molded into the tank its HDPE.

The fact is if its HDPE it probably never cracked to beging with so its a moot point. Its a better material for a tank than abs.
LarryJM
Explorer II
Sep 14, 2018
Ralph Cramden wrote:
Just because its colored black means nothing. Alpha Systems tanks are on many RVs. Theyre black and are not ABS, they're HDPE.

ALPHA SYSTEMS

It's really easy to determine ... just wet the tank with Acetone and if it becomes sticky its ABS unless some other material dissolves like ABS to Acetone.

Larry
Ralph_Cramden
Explorer II
Sep 14, 2018
Ralph Cramden wrote:
Ralph Cramden wrote:
Just because its colored black means nothing. Alpha Systems tanks are on many RVs. They're black and are not ABS, they're HDPE. You cna attempt to glue, flexseal, or essentially cobble together a repair, but if the tank is blow molded HDPE the only permanent solutions that can be counted on 100% are either new tank or plastic welding.

ALPHA SYSTEMS

And why in the hell doesn't this board have a delete function for when you try and edit and mistakingly hit the quote button. You would think based on the net worth and business dealings of Marcus Lemonis, the board associated with his company would not be running software developed in the days of the Packard Bell X86 pcs LOL.
Ralph_Cramden
Explorer II
Sep 14, 2018
Ralph Cramden wrote:
Just because its colored black means nothing. Alpha Systems tanks are on many RVs. They're black and are not ABS, they're HDPE. You cna attempt to glue, flexseal, or essentially cobble together a repair, but if the tank is blow molded HDPE the only permanent solutions that can be counted on 100% are either new tank or plastic welding.

ALPHA SYSTEMS
Ralph_Cramden
Explorer II
Sep 14, 2018
Just because its colored black means nothing. Alpha Systems tanks are on many RVs. Theyre black and are not ABS, they're HDPE.

ALPHA SYSTEMS
LarryJM
Explorer II
Sep 14, 2018
Drew A. wrote:
opnspaces wrote:
I used plastimend on the rear wall of my black tank. So far it has held up and I don't see any reason that it would fail. They do provide a small piece of fiberglass window screen to use for reinforcement. I bought a bit more screen to make sure it was well supported.

This is probably nothing more than Acetone and ABS chips, but it worked for me so I'm happy.

Link

X2 on this stuff. It works great. Fixed my black tank at a crack where the outlet pipe is. It's now better than new. Not worth doctoring up your own concoction of ABS in my opinion.

Except for the fact that the Plastimend kit will run you 2 to 4 times as much as a qt of acetone and some ABS material. Also, you'll have a bunch of Acetone leftover for other uses.

Larry
Drew_A_
Explorer
Sep 14, 2018
opnspaces wrote:
I used plastimend on the rear wall of my black tank. So far it has held up and I don't see any reason that it would fail. They do provide a small piece of fiberglass window screen to use for reinforcement. I bought a bit more screen to make sure it was well supported.

This is probably nothing more than Acetone and ABS chips, but it worked for me so I'm happy.

Link

X2 on this stuff. It works great. Fixed my black tank at a crack where the outlet pipe is. It's now better than new. Not worth doctoring up your own concoction of ABS in my opinion.
LarryJM
Explorer II
Sep 14, 2018
mobeewan wrote:
In stead of dissolving a piece of ABS sheet you can also do the same with a piece of ABS pipe or ABS fitting to make a paste.

If it is a small crack you might be able to just use ABS glue painted over the crack after cleaning if up and excavating it instead of making a paste.

While some ABS glue has ABS Resin in it not all do and even the glue with the Resin in it isn't IIRC more than about 40% resin. It appears that both the clear and cream colored ABS glue doesn't have resin, but the black from Oatey does. For those reasons I did not include nor really recommend using ABS glue for a repair like this.

When making a paste just remember it takes some time for the Acetone to fully dissolve the ABS and you really want the paste to be smooth w/o any lumps. It took me a couple of days to make a shot glass sized amount of paste dissolve pieces of ABS about 1/8 the size of a pencil eraser.

Larry
landyacht318
Explorer
Sep 14, 2018
Amazing goop has a Marine version too. I've not tried it. Says it is UV resistant, which the regular version most definitely is NOT. They actually have several different versions.

Sanding with 80 grit for mechanical tooth is wise, but also wise to wipe with a solvent before using fresh new sandpaper and scuffing in a cross hatch pattern. No point in pushing containants into the sanding grooves

I have saturated light weight fiberglass cloth with Amazing Goop. thicker cloth does not saturate completely but still aids repairs, especially on those repairs needing to remain flexible.