Fresh water tank for black water?

[T-Bolt]

I can't find a black tank in the dimensions that work for me. Is there a reason I'm not thinking of as to why a freshwater tank couldn't be used? It will be painted black and installed with a slight slope.

 

[Danjo-SKO]

Sure you can, but you would want a 3” outlet on it and it needs to be low on the tank side. Get a place to spin weld a 3” fitting and you’re good. Make sure you can get the fitting and the place to do it before you buy the tank. You’ll also want an 1 1/2” vent connection in the top.

 

[Danjo-SKO]

Sure you can, but you would want a 3” outlet on it and it needs to be low on the tank side. Get a place to spin weld a 3” fitting and you’re good. Make sure you can get the fitting and the place to do it before you buy the tank. You’ll also want an 1 1/2” vent connection in the top.

And I’ll follow that up with, keep looking for a proper black tank. It will drain better

 

[Shamoke]

And I’ll follow that up with, keep looking for a proper black tank. It will drain better

Agreed. By the time you paid a shop to modify the grey tank to suit your needs you could probably custom order a black tank the size your needing. I found several sites that claim to make custom sized RV tanks.

Here is one: https://www.all-rite.com/custom-holding-and-water-tanks-1452.html

Here is a site listing many sizes of black holding tanks: This site is selling used holding tanks, just saw that after I posted this.
https://www.ntotank.com/rv-black-water-tanks

 

[T-Bolt]

There are a few reasons why I'm thinking of going this route.

I have a very specific size and dimensions that will fit my needs. Countless hours of searching online yielded a few options that would work. I contacted the company and they are "custom" and would take 6+ weeks but due to covid there is no guarantee on timeline. It is also nonrefundable.

The fresh tank is 1/4 the price and will be here in 2 days.

My plan is to get a flange like the one pictured. I have a CNC so I will make a 2 peice bolting flange to go on the inside from HDPE. It will be installed with a good sealant and stainless steel bolts.

 

[ol trunt]

I expect you are talking about the milky white polyethylene tanks (not polypropylene). If so, your best bet for adding fittings is spin welding. Here are two sites worth looking at:

https://spinwelding.com/spin-welding.html

https://www.icondirect.com/fresh-water-tanks-1/

You will be hard pressed to find "good sealant" for use with polyethylene--nothing sticks to it.

Spin welding is easy to do yourself with a router and a spin weld driver. I made up my own drivers and whipped out three tanks in a morning's time. That was nearly 10 years ago and no leaks yet.
Jack

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[TJones-SKO]

You could use a bulk head fitting like this.

https://www.amazon.com/Banjo-Polypropylene-Bulkhead-Tank-Fitting/dp/B08K2MG99J

Ted

 

[Danjo-SKO]

Camping World locations usually will do it.

The place I got my tanks (through tank-mart) charged 5 bucks a fitting.

 

[MastersOfSky]

Spin welding DIY bits/drivers

I've looked at spin welding "bits" wild expensive where I live (Canada). how did you make your own bits?

I expect you are talking about the milky white polyethylene tanks (not polypropylene). If so, your best bet for adding fittings is spin welding. Here are two sites worth looking at:

https://spinwelding.com/spin-welding.html

https://www.icondirect.com/fresh-water-tanks-1/

You will be hard pressed to find "good sealant" for use with polyethylene--nothing sticks to it.

Spin welding is easy to do yourself with a router and a spin weld driver. I made up my own drivers and whipped out three tanks in a morning's time. That was nearly 10 years ago and no leaks yet.
Jack

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.

.

 

[s2mikon]

Here is another reason to use a real black water tank. It keeps anyone from seeing the Captain's logs.

 

[Kentucky Dreaming]

Stardate, next weekend.

These are the voyages of the starship Enterprise, It's 5 year mission: to explore strange new worlds, to seek out new civilizations. To boldly go where no man has gone before, man....

James Tiberius Kirk