Fittings for polly water tank

[ventport]

I am looking for some fittings that fit in a drilled hole in a polly water tank that expand when tightened and become water tight, all from the outside of the tank. I have used them before but can't remember what they are called or where to get them. I need to put a water fill (1 1/4" I believe) fitting in a new polly tank, and do not have the equipment to spin weld them on. I also cannot buy a tank with the fitting where I need it. The fittings I am looking for work kind of like the old lever style bottle stoppers, where you flipped down a lever and the rubber part in the neck of the bottle expanded. Anyone know what they are called and where to get them?

[GMFL]

A boat plug?
https://www.westmarine.com/buy/west-...07?recordNum=1

[dbj216]

Hi Ventport: What a great user name for your tread subject! I like it.

I might suggest a rubber grommet fitting for your fill port. I have used them successfully in my holding tanks, and my application was the top surface of the tank, for vent ports and the like.

The rubber grommet fitting is installed after the right size hole is cut with a hole saw into the tank. Then the grommet is worked into the hole. It is a press fit on the OD of the hole. There is a tight fitting rubber flange around the surfaces of the hole. Then a 1 1/2" ID ABS pipe is pressed into the grommet. It is also a press fit, and puts additional pressure on the tank seal.

Take a look...

David

http://www.vintagetrailersupply.com/category-s/439.htm

[ventport]

Thanks for the reply. The ventport handle is because I own a 1949 Buick, the first year for the holes in the front fenders called Ventiports. The rubber grommet may be the answer for my problem. And yes the boat plug is what I was talking about. But the fitting I used had a hole in the middle for water flow, and rubber around it with a nut on the outside. When you tightened the nut it would expand the rubber thus sealing the fitting to the tank, just like the plug posted.

[Bigventure]

I would think a 1 1/4 floor flange would work. Just sandwich a full face gasket between it and the tank.

[AFTER TAXES]

even walmart......

[ventport]

Originally Posted by Bigventure

I would think a 1 1/4 floor flange would work. Just sandwich a full face gasket between it and the tank.

How would I fasten it to the top of the tank? Screws?

[Bigventure]

Well there will be an 1 1/4 hole, so you could put a carriage bolt in the tank with the threads up. Or a bolt and washer. It’s a pain and you would need a magnet for when you drop one in the tank.

Or use an 1 1/4 male adapter and silicone or JB weld it on.