Glue or clamp flange to black tank?

[pilgrim_still]

I posted this question in a previous thread, but that subject line seems irrelevant. So, a new thread...

My Thetford valve has arrived and is ready to install. Thanks ericandterry.

When I removed the old valve, the flange to the tank came off. A previous "repair" by a PO had used a radiator clamp and a putty-like substance (I said "putty-like", not "potty-like"). A local plumbing supply store employee suggested using Oatey All Purpose Cement (for PVC, ABS, CPVC) to replace the flange in the tank.

What is the forum's opinion about cementing the flange (to which the Thetford valve attaches) to the black tank?

Any votes for a friction fit and a radiator hose clamp?

[Lexxy]

...but we are just patching a tank where someone did just that ...cemented the hell out of it and it's a mess. We had to cut the valve out [actually it melted out] and construct a new hole with a new pvc flange [glued and bolted in] that may or may not work to avoid a new $400+ tank. We have decided to let this valve float in the hole we made since the fit is so tight and it will allow some up and down movement for vibration.

Think about it...it's part of the tank forever and you can never remover the tank with out cutting it out!!!

[john hd]

my grey water valve pipe is a slip fit with a hose clamp.

it is sealed with vulkem on the pipe.

found it to be still pliable after ten years.

i discovered it when doing this

john

[pilgrim_still]

John,
You said the Vulkem was still pliable after 10 years, but you just did this repair??!!
Both you and Lexxy had/have flanges cemented into the tank. He plugged and re-flanged. You dropped down a size and fit your new pipe inside the old flange. Right?
So, how come my flange came out of the tank? The putty-like material I discovered on my flange may have been Vulkem -- it was grey. There was a radiator hose clamp on it, too. But, I didn't see anything that looked like cement.
That is why I posed this question about the best way to reinstall the flange.

John, if your flange had not broken, how would you have replaced it?

[john hd]

jim

mine never had a flange. it is as built in ohio.

just did the repair this spring, the old original vulkem from the factory is what i was referring to. my trailer is just over ten years old. i expect the new vulkem to stay just as pliable over time.

the pipe that i repaired is exactly the same size as before. just a slip fit with vulkem.

how would i have removed it if it were not broken?

i would have just loosened the clamp and pulled the whole assembly out as a unit.

i think you are confused because i added the pipe to the assembly. it replicates what was there from the factory. just slightly different fittings were used, same end result.

the pipe on mine slides into the tank with vulkem and is held with a hose clamp. simple and no leaks!!

john

[pjlingl]

Pilgrim
I stuck with the clamps. I had a tank leak a couple of years ago and found the flanges were also cracked. If you glue them, you got a real problem when you have to change them down the road. I used buytl caulk (for gutters) from Home Depot. It stays pliable and nothing will touch it but mineral spirits, thus easy to clean later if you need to take it apart. Nice and tight - no leaks since. Good Luck. Jeff

[Ken J]

My vote would be clamps if you can get them to work - glue is hard to undo later.

Ken J.

[ericandterry]

Hello again...

Please don't glue it !!!! Save the next owner from chiseling it out of the tank like I had to do. I went with two clamps just to be safe and it's been working great. Try it first , if you find it's not adequate then think about glueing.
I'm glad I could help on the flange location. Saving someone else the pain, suffering, time and long distance calls makes me happy , American way is top notch to deal with and getting NOS parts is fantastic too.
Good Luck
Eric

[Ken J]

Wow two clamps - thats a great idea - I'm in the middle of replacing my valves, think I'll do that.

Ken J.