New Holding Tank Fittings?

I finally got my stainless steel holding tank out with a come along. I have a new custom made plastic tank that I need to put fittings on. Has anyone done this? I ordered the new tank with no fittings because I didnt know where they needed to be until I got the old one out. How do they put these fittings in at rhe factory? Can I do this myself? How do I get flanges inside?? I found a "relocation," diy kit that includes a big port that I assume is to allow you to get the flanges inside and it's got a big o ring to seal it back up. Anybody ever use one of these kits? How do they do it at the factory??

Had mine made. Different ways to do it. Does it have baffles inside? Suggestion is to put all fittings on the top so that you don’t have the worries of fittings leaking. And at least an inch diameter vent (2 would be better) you and those next to you will appreciate it in the future.

Any idea how I install fittings?

Bigfish said:

Any idea how I install fittings?

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Buy the kit. I would expect it to have instructions. If not, it should be obvious.

MYMT said:

Had mine made. Different ways to do it. Does it have baffles inside? Suggestion is to put all fittings on the top so that you don’t have the worries of fittings leaking. .......

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If you put the outlet on the top it will suck air. The outlet has to be on the bottom or on a side as close to the bottom as possible. The inlet and the vent should be on or near the top.

There are a couple of different types of tank fittings that are do it yourself. Post a picture of the fitting and maybe someone here can help. You also might call who ever you bought the fittings from and ask them.

I have always bought tanks from Ronco Plastics and had them install the fittings. I think they spin weld the fittings onto the tank.

I really don’t. I know they used pvc fittings and pipe to go from the topside to the bottom of the tank where I had them cut the bottom of the pipe at an angle so that if the pipe became dislodged it wouldn’t fall over and at the same time wouldn’t lay flat on the bottom unable to suck the contents out. One for Pumpout and one for overboard discharge. I do remember them having to reduce the pipes outside diameter a bit to be able to fit it into the factory fittings. Inch and a half on the discharge hose side, I’m thinking it may have been inch pipe inside to fit. Not sure, but I’ll bet Home Depot would have the fittings you’d need.
I’ll be back there in about a month or so, give you a hand with it if need be. Glad you survived the storm.

Are they Uniseal fittings? I think Peggie Hall favors Uniseal fittings.
Here is a video on how to install them.

They used PVC glue adhesive to put the fittings together.

Thanks folks.. No video showed up but I'll track it down! I have not bought the fittings yet. Peggy Hall! Thanks for reminding me. She will know the best way to proceed!!

Bigfish said:

Thanks folks.. No video showed up but I'll track it down! I have not bought the fittings yet. Peggy Hall! Thanks for reminding me. She will know the best way to proceed!!

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Yup...we need to talk to figure out where the fittings CAN go and how to do it. So send me a PM that includes your email address and we'll go from there.

Meanwhile, here's the link to the Uniseal that includes instructions so you can get an idea of what it is and how it works: UNISEAL

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

Thanks! Sent you a message

For the smaller hose connections you might want to use a "spud" or "blind bulkhead fitting".
Like the Uniseal they allow you to attach fittings to the tank without access to the inside of the tank. These are threaded so it's easy to attach hose barbs to them. I haven't seen them big enough for the 1-1/2 hose you'll use for the pump out, but for 1" (vent?) or smaller lines they should work well. USI-RV Bulkhead Blind Tank Fittings

Spendy!

Bigfish said:

Thanks! Sent you a message

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Just replied to your email.

Parks, not only is that thing VERY "spendy," but it appears in the illustration that part of it is metal, which isn't the best thing to use in a waste tank. Interesting though.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

WesK said:

If you put the outlet on the top it will suck air. The outlet has to be on the bottom or on a side as close to the bottom as possible. The inlet and the vent should be on or near the top.

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Use a tank dip tube mounted in the top of the tank. This way, there is no standing waste in the head discharge lines to eventually permeate and stink, and in the event they become clogged, they can be withdrawn and cleared easily with minimal mess. All of the majors make these kits. No leaking fittings on the sides or bottom of the holding tanks.

The "sealing grommet" in those kits are Uniseals. Easy to DIY fabricate for considerably less than the kits...the SeaLand version has a list price of about $50!

HeadMistress said:

Just replied to your email.

Parks, not only is that thing VERY "spendy," but it appears in the illustration that part of it is metal, which isn't the best thing to use in a waste tank. Interesting though.

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein

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Yup those are pricy. Call Mac at Raritan and ask him for a bowl spud. Same thing, 1" thread (I think, maybe 3/4), all plastic, and should be less than twenty bucks. You can get them from Groco too.

Normally tank fittings are spun in place.

A hole is cut and the fitting is placed on the hole ans a good sized (2hp) router with a fitting simply spins the fitting till both the firring and tank melt a bit from the friction.

It is a no brainer (except for cutting the hole in the right location) and usually a new hire job after 5 min of instruction.

Many places use plastic tanks , if you don't have a big router , you can visit any tank fabricator and they can install the fittings , it takes longer to drill the hole than spin weld the fitting.

Three fittings in top...vent, inlet, discharge. As others have said use a dip tube for discharge/suction out.

All my fittings on my tanks are 1.5"

Use grommets if you didn't get fittings welded into tank, or try to weld them in yourself as Fred described.

McMaster has a any size and style grommet you'll need, and their delivery is insanely fast.

Conall

Larry's illustrations (post #16) are useful. Would also want a vent line fitting.

Recently had some discussion with Peggie in another thread about whether I might be moving our original side fittings to overhead. The Uniseal solution (sealing grommets, in the diagrams) looks like better than sliced bread. In case folks didn't see it in the other thread, Peggie recommended a 25° angled cut at the bottom of the discharge dip tube, essentially replacing the "shoe" at the bottom of the dip tube diagrams.

I'm thinking I could have a T at the top of our discharge dip tube, one to hose leading to the the deck pump-out fitting, and the other to hose leading to the overboard discharge macerator. Pros and cons to the T idea, I suspect.

-Chris

The T idea is a good one. I T’d the discharge tube to enable a Pumpout on either side which has proved useful. My overboard discharge has its own tube. Has worked well for me.

Thanks everybody! I ordered uniseals that should arrive tomorrow. I think I'm going to be ok!! Anxious to get her all back together. Thinking I may take a trip to the exumas next, maybe beyond. Suffering from a bad case of getmeoutoftheharboritis...

LarryM said:

Use a tank dip tube mounted in the top of the tank. This way, there is no standing waste in the head discharge lines to eventually permeate and stink, and in the event they become clogged, they can be withdrawn and cleared easily with minimal mess. All of the majors make these kits. No leaking fittings on the sides or bottom of the holding tanks.

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Yea, I know that but the poster I was responding to just said to put the fittings on the top of the tank. He said nothing about dip tubes.

ranger42c said:

Larry's illustrations (post #16) are useful. Would also want a vent line fitting.

Recently had some discussion with Peggie in another thread about whether I might be moving our original side fittings to overhead. The Uniseal solution (sealing grommets, in the diagrams) looks like better than sliced bread. In case folks didn't see it in the other thread, Peggie recommended a 25° angled cut at the bottom of the discharge dip tube, essentially replacing the "shoe" at the bottom of the dip tube diagrams.

I'm thinking I could have a T at the top of our discharge dip tube, one to hose leading to the the deck pump-out fitting, and the other to hose leading to the overboard discharge macerator. Pros and cons to the T idea, I suspect.

-Chris

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I would use a "Y", not a "T". It will be easier for sewage to flow through with less chance of a clog.

As for moving the side fittings to the top to avoid standing sewage in the hoses, why not use PVC pipe from the side discharge to the top and attach the hoses to the PVC? Essentially a dip tube on the outside of the tank. That would be a lot less work and expense.

WesK said:

I would use a "Y", not a "T". It will be easier for sewage to flow through with less chance of a clog.

As for moving the side fittings to the top to avoid standing sewage in the hoses, why not use PVC pipe from the side discharge to the top and attach the hoses to the PVC? Essentially a dip tube on the outside of the tank. That would be a lot less work and expense.

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If I'm not mistaken, that is called a 'standpipe' and is a superb suggestion for an existing system.



Personally, I would only go to the trouble of top-mounting a dip tube on a new installation.

I think I know how I'm going to do this!! Thanks everyone

I don't know why you'd consider a standpipe to be easier than a diptube. With a diptube, you have a piece of PVC pipe and one 90 degree hose fitting on the top of the tank. With a standpipe--as your illustration clearly shows--you need a tank fitting, a short piece of hose, a coupling, a 90, a piece of pvc and another 90 plus anaother coupler to attach a hose.

But it's your boat, bigfish...do whatever floats it for you.

I decided on the diptube!!

WesK said:

I would use a "Y", not a "T". It will be easier for sewage to flow through with less chance of a clog.

As for moving the side fittings to the top to avoid standing sewage in the hoses, why not use PVC pipe from the side discharge to the top and attach the hoses to the PVC? Essentially a dip tube on the outside of the tank. That would be a lot less work and expense.

Click to expand...

LarryM said:

If I'm not mistaken, that is called a 'standpipe' and is a superb suggestion for an existing system.

Personally, I would only go to the trouble of top-mounting a dip tube on a new installation.

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Good points. FWIW, moving our inlet and vent hoses to the top would gain us some capacity, and that was my original focus.

Moving the outlet hoses to the top... was more of an optional idea. It MIGHT gain some capacity, if the dip tube bottoms out slightly lower than our current T fitting, but I doubt it'd be much gain.

And given that I don't often have to service our macerator pump (which hasn't worked in a few years anyway)... and the existing outlet hose from tank fitting to pump shows no signs of permeation... doing the extra work to relocate the outies may well be not much worth the effort. IOW, for this part of it, doing nothing is maybe a good option, too.

-Chris