Sealand M65 Tank Outlet: Bulkhead vs Spin Weld

[TammyandTony]

Our Electra-Magic is hitting end of life.
Looking at floor (and toe) space, I'm settled on an M65.
I'm having a hard time finding someone to do the spin weld. Wondering what the drawbacks would be to a 3" bulkhead connector.

I'd also like to hear if anyone has installed and M65 and any tips.

Thanks,

 

[jagizzi]

Some great info on the install here: Installing a Sealand 711-M28C with 3" Gravity Discharge

And Allen Lee has his install documented on the Facebook Group and it is a great resource.

My only addition to the installs that you should run through bolts through the floor to large fender washers to secure the back of the toilet. The toilet is front heavy and lag bolts, even when set in epoxy plugs, which was my initial solution, pull out of the floor and the toilet tips during bumpy rides.

 

[Shane826]

Here’s the link to Allen Lee’s install on TMF.

Facebook

He was the guinea pig for a couple add-ons I had been kicking around for my TM. The Tornado rinser and floor gate valve were a big success. The only thing we both agreed should change is to not vent down through the floor, it causes the toilet to burp when flushed. Run the vent hose vertical a few inches then out the side wall.

PS- What is the M65?

 

[TammyandTony]

Thanks all, I got a lot of info from the FB post.
I don't normally use that for a reference - figure anything worthwhile is here.

I do plan on a 2nd gate valve as close to the tank as possible.

The Dometic/Sealand M65-700 and -5000 are the newer versions of gravity flush toilets. They have a smaller tank (6.5 G), but are the same ~19" width, less intrusion into the floor space and are lower -the same as in our bath at home.

The M65-700 seems a better choice for us, though we haven't decided yet. Not even sure we can still get a M28 any more.

Still curious about using a bulkhead adapter instead of spin welding. The bulkhead will leave a 1/4" or so puddle in the bottom of the tank. Is spin welding flush to the bottom?
Otherwise, the flexibility of precisely placing the clean-out is appealing, so is the speed of getting a standard part without waiting for special work.

Appreciate any (more) thoughts.

 

[Bill]

Still curious about using a bulkhead adapter instead of spin welding. The bulkhead will leave a 1/4" or so puddle in the bottom of the tank. Is spin welding flush to the bottom?

I have not done this, so take it for what it is worth. Being curious, I pulled up a couple YouTube videos about spin-welding fittings into a plastic RV black tank. They mention. and seem to show, that a properly chosen tank outlet fitting will be flush with the floor of the tank. But it also suggests that DIY spin welding is not for the faint of heart. I'm not sure how you would get a bulkhead fitting into a tank, but as I say, I have not done it. I doubt that it would be flush with the floor. Here is one video, take a look at about 7:30-7:45 into it. There are others.

The existence of a standing puddle of "stuff" would make me nervous. If the "stuff" hardens or even gets sticky, it might be very hard to remove, and won't smell good. I imagine that you would need to spend time with a water jet cleaner/rinser to avoid it, and unless you have hookups, that increases water consumption and black tank load.

Let us know how you proceed.

 

[Shane826]

Wow I hadn’t seen those. The lower capacity is concerning but imagine all the extra foot room!

Spin weld. You don’t want anything raised above the floor of the tank. Ew.

 

[TammyandTony]

Appreciate the info.
We're going with the 711.
Ardemco has the bottom drain tank (bone only) in stock, we should have it next week. Even able to get a white fixture.