New black tank, cutting a new hole?

[akmntman]

I have gutted my as and I am finishing up the floor. I purchased a new black tank and toilet. I need to cut a hole in the tank to mount the toilet flange. I am trying to figure out how to secure it, the easiest way would be to glue the end of the flange to the tank because there is only a two inche gap between the two, but I am worried if i have to remove the flange it could be an issue. the original tank was glued directly to the tank and a section of the floor came up with it. any help would be great.
m

[easyride]

If I`m remembering correctly,I had a female threaded flange that glued to tank,then I had the toilet flange that screwed into it,and screwed down to the floor. Dave

[wkerfoot]

Originally Posted by easyride

If I`m remembering correctly,I had a female threaded flange that glued to tank,then I had the toilet flange that screwed into it,and screwed down to the floor. Dave

That is the way my new black tank works in the Liner.

Bill

[68 TWind]

On a 68 the black tank had a female flange on top of the tank. A short "nipple" threads into the flange on top of the tank and then the closet flange screws onto it from the top. Then the closet (or toilet) flange is secured to the floor and the toilet is attached to that. The flange is not a standard flange as most flanges now days are not threaded, designed to be glued to PVC waste lines. My local ACE hardward had the threaded toilet flange.
As for cutting the hole in the top of the new tank, I would recommend that you raise the new tank into position under the trailer and get it exactly where it needs to be, then from the top mark the new black tank through the hole in the bathroom floor. If the new tank is fiberglass, you just use a fiberglass kit ( Home Depot has them), to glass the flange to the top of the black tank. The flange for the top of my black tank was included in the box that I purchased from Inland.

[akmntman]

Thanks guys that is what I was thinking my plumber friend was worried about leakage but the systems not pressurized so I see no problem. Vulkum on the threads or Teflon?

[akmntman]

Problem. Tanks made "we think" HDPE. Glue won't stick to it. Gonna have to have a flange spund into the tank or welded

[wkerfoot]

Originally Posted by akmntman

Problem. Tanks made "we think" HDPE. Glue won't stick to it. Gonna have to have a flange spund into the tank or welded

I believe that the fittings are usually spun in.

Bill

[InsideOut]

I took our tanks to a local shop that spun all our fittings in - I think they charged me $20 for all the fittings (6 or 7 - I don't recall) including installing them on all three tanks...and I got to watch, super cool!

Shari

[akmntman]

went to the rv supply shop, they informed me that they could spin the fitting in, then informed me that they didnt have the fittings for the poly tanks. So I am going to use the rubber seal and silicone. I think it will work fine. the limited room between the floor and tank the closet flange will slide right in with silicone. what do you guys think about this set up?