Connection Between 3" Pipe and Black Tank

[Midwilshire]

We purchased used tanks onto which the previous owner had welded all fittings except the drop from the toilet.  I was planning on welding a 3" fitting for that, but came across this grommet:



This would be an easy and fast solution.  Our toilet sits directly on top of the tank, and the tank is tightly secured in place.  Does anyone have any experience with this type of grommet?  Do they work well?  Would you recommend any sealant to supplement the seal? 

Thanks!

[Van]

We used this fitting on our Poly tank, straight drop in with no issues and no sealant. 8.99 here. Pretty common in the rv industry
http://www.go-rv.com/coast/do/catalog/page?dealerId=1331&pageNum=418&productId=21290

[Jriddle]

We used this fitting on our Poly tank, straight drop in with no issues and no sealant. 8.99 here. Pretty common in the rv industry
http://www.go-rv.com/coast/do/catalog/page?dealerId=1331&pageNum=418&productId=21290

Yup what I used also works fine. Make sure to cut the hole the right size for the grommet.

John

[Iceni John]

I used two of the smaller size of this grommet for the gravity-fill inlets into the tops of my fresh water tanks, because those tanks' inlets had to be self-connecting as I raised them up into position under the floor.   Make sure your tank's wall thickness matches the grommet  -  if your tank's too thick you may need to shave down the opening slightly.   3" ABS pipe should fit easily through it, but if it hangs up and tries to dislodge the grommet from the opening (that happenend with me, twice ) some imaginative folk recommend a water-based non-toxic readily-available biodegradable lubricant, i.e. KY Jelly!   It's also a good idea to chamfer the bottom of the poo pipe so it will slip through better.

John

[belfert]

I used one of those grommets for my 3" pipe and it works great.  I even used one for the bottom drain and no leaks yet.  I would not recommend for the drain!  I think I'm running on borrowed time using this for the drain.

[gus]

You can also find just plain rubber sleeves of different lengths at your local hardware store.

In any case sewer pipes of any length need a couple of flexible joints for vibration resistance and for easy maintenance.

[Midwilshire]

Thanks for the confirmations, gents!

[Nick Badame Refrig/ACC]

Hi Mike,

I also used the same fitting with no problems!

Good Luck
Nick-

[Van]

If you size the hole correctly, the seal will expand slightly in the hole and will make a nice seal with no sealant required. Be sure to properly add a tank vent also  I used a little 40 wt oil to easily insert the pipe