Blocking Up Tub Outlet
 

Hey i have a 45ltr hydroponics resivoir tub that has 2 x 32mm tub outlets on it, one on each side and i want to relocate one of them and put it on the other side a few inches from the other outlet. I want to do this because it will be better for the way i will be plumbing it up, if i dont move it i will have to use a couple of elbows to get it to the other side and it would be best not to use many elbows when it can be avoided. My problem is what to do with the 32mm hole left in the tub when i move the tub outlet, originally i was going to leave the outlet there and use a short piece if pipe with an end plug in it so it will be blocked, and then i would just buy another tub outlet to use on the other side, but i would like to be able to not have a bit of pipe sticking out of the end of the tub if i can, so i have been searching for some kind of fitting that blocks the hole but i couldnt find anyone that makes one. It would be so simple for a company to make one.
So does anyone know of any fitting that is made to block a 32mm hole in a tub?
What other ways could i do this? i was thinking i could get a square piece of plastic and put some waterproof silicone around the hole on the inside of the tub and put the square on it and let it dry, that would do it but i would love to just be able to put some kind of fitting in there to block it off though.
So what are your thoughts?

Hello MickR33,
You might be able to use something like this Oatey 1.5 Dia PVC Test Plug Fitting as a temporary fitting. But I don't think it would be durable enough to to last long, or the metal screw from corroding. But who knows, I haven't tried using one myself...

It sounds like the opening is a little smaller than 1-1/2 inches wide. First if you plan to patch it, I would make sure to screw or bolt the patch to keep it in place and durable. I would also use pluming goop, it's strong and 100% waterproof. But I would also want to scuff both sides for better bonding. You also mention the Tub but don't say what kind of material the tub is made of. There's a big difference between a fiberglass tub and a metal tub with a enamel finish. It would be hard to bond anything well with an enamel finish, that's one of the reasons I say I would screw or bolt the patch on securely. Then once glued in place with the pluming goop, and screwed down, cover the screw/bolt heads with pluming goop to water proof them too.

But with all that said, I would probably just make my own "through hole"/"Bulkhead fitting"fitting with PVC fittings. I attached some pictures. The gray one is a typical through hole used by electricians. I got it to use on the bottom of some 5 gallon buckets I needed to attach a vinyl tube (drain line) to. The vinyl tube connected to the barbed end. In case you don't know what a through hole/bulkhead fitting is, it's fairly simple. It consists of two parts. The small side of the big part goes through the hole, and the other part screws onto the first part. When screwed down it clamps on. It also often has a O-ring or some type of gasket to waterproof it.

The white PVC fittings are what I used to make my own through hole. You can see it installed on the upside down bucket. I needed to make some spacers to get it to tighten down all the way good and tight though. In the picture I used silicone to water proof it instead of using a gasket. That was a mistake and those buckets needed to be redone. I later found out that silicone will never bond properly to that type of plastic and pealed off easily. So I should have just made a rubber gasket for it to begin with. Oh well, live and learn right?

Anyhow, If your using a material/plastic that you can glue properly. You can glue it in place when you tighten it down with pluming goop or a two part epoxy that bonds to both PVC and whatever material your using. But beware to make sure it bonds to both. I like gluing it in if I can to make it more durable. But Tupperware and buckets (smooth plastics) tend to have stain resistors in them, and those stain resistors keep anything from bonding with it. Those type of plastics just use a rubber type of gasket on the inside. I don't think you will get anything to bond to enamel finishes either. I even used a cheap foam rubber hat to make gaskets with (I attached pictures). You can also check the pluming department for rubber sheets to make custom gaskets with, or use any piece of rubber or vinyl big enough to make your own gasket with.

If you make your own PVC through hole/bulkhead fitting, you can just screw on a PVC plug adapter to cap it off. Or you can screw on a PVC ball valve like these:

Ball valve 1

Ball valve 2