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Fittings for holding tank revision.

PrivatePilot
Explorer
Explorer
Hey all. It's a long story but I'm redoing a mixed black/grey (solo) holding tank on our latest micro-trailer and making it strictly grey and then adding a cartridge toilet instead. The existing tank was leaky, the single mixed tank wasn't ideal, and when I dropped it, it didn't take me long to figure out why it was leaky - the installation (either factory, or some previous owners modification) was a gong show with caulking trying to make up for it.

Anyhow, I have the tank at a reputable plastic welding shop getting returned to basically new (and hole-less) condition. It's in otherwise good condition and was a waste to throw away when I could get it fully repaired for 1/3 the cost.

For the revised setup I need 3 (probably 1" will be fine) holes on the top of the tank near where the toilet used to drain into. 1 for the galley sink, 1 for the shower, and 1 for the vent.

I'm struggling to figure out what fittings may work best for mating onto a flush ABS surface. Ideally I want them as flush as possible, and threaded - that way I can adapt whatever fittings I need externally beyond that point.

Anyone have any suggestions?
30' Keystone Cougar 5'er, Triple Bunkhouse, SuperSlide.
Chevy 3500 1 Ton long box crew cab dually
6.5 Turbo Diesel, 4.11 Rears, LSD, Fresh rebuild spring 2012.
Dieselplace.com Staff Member

Our 2008 western adventure - to the coast and back!

Mark
3 REPLIES 3

PrivatePilot
Explorer
Explorer
QCMan wrote:
If you are draining a sink into the tank you will need 1 1/4" pipe minimum and 1 1/2" would be ideal. Less and you will be waiting a while to drain as you would be creating a funnel. Likewise, the vent line should be the same size as the drain line even if you use an under sink vent stack with a vent valve on it. Shower should be the size of the fitting that is attached to the shower pan/tub for the same reason as the sink.


Thanks. Not too worried about the sink taking a bit longer to drain, it is quite small - this is a tiny trailer afterall.

I think I found a combination that will work at HD.
30' Keystone Cougar 5'er, Triple Bunkhouse, SuperSlide.
Chevy 3500 1 Ton long box crew cab dually
6.5 Turbo Diesel, 4.11 Rears, LSD, Fresh rebuild spring 2012.
Dieselplace.com Staff Member

Our 2008 western adventure - to the coast and back!

Mark

Darryl_Rita
Explorer
Explorer
Talk to the guys at the welding shop, they can spin weld fittings in that will work with the ABS of the trailer.
***UPDATE 2006 3500 SRW MegaCab pulling a 2007 fleetwood 5'er

QCMan
Nomad III
Nomad III
If you are draining a sink into the tank you will need 1 1/4" pipe minimum and 1 1/2" would be ideal. Less and you will be waiting a while to drain as you would be creating a funnel. Likewise, the vent line should be the same size as the drain line even if you use an under sink vent stack with a vent valve on it. Shower should be the size of the fitting that is attached to the shower pan/tub for the same reason as the sink.

2020 Keystone Cougar 22RBS, Ram 1500, two Jacks and plenty of time to roam!
The difference between genius and stupidity is that genius has its limits. A.E.
Good Sam Life Member