tanks

[charlieward]

Besides price, what are disadvantages of building rest and grey water tanks out of aluminum? Weigh, etc?

[HiJoeSilver]

Other than cost, coming up with a good way of attaching all the piping may be difficult too. Not sure what you'd use for tank level indicators as well, I don't think the type that stick to the tank side will read through the metal. They will weigh more than plastic.

[Wolfe]

endless welding, winter frezeing if full, no round corners,ect,ect

[Jammer]

Possible corrosion problems.

[Protagonist]

Bleach and aluminum don't mix well, either. Granted, the concentration of bleach is low when you're sanitizing the tank, and you don't sanitize very often, but there is a slight risk of damage to the tank if you overdo the bleach.

Also, if you use aluminum, make sure you use a food-safe alloy for the fresh tank. 6061 is a corrosion-resistant alloy, and is also considered food-safe according to ANSI/NSF 51. The sticking point here is that the welding rod (or welding wire) isn't necessarily food-safe, even if the aluminum sheet is.

[charlieward]

Thank you. aluminum tank idea has been discarded. Any suggestions as far as gallon size for fresh and grey? In the event we change our minds and go with black water tank, how many gallons? Thanks

[charlieward]

Thank you. aluminum tank idea has been discarded. Any suggestions as far as gallon size for fresh and grey? In the event we change our minds and go with black water tank, how many gallons? Thanks

[HiJoeSilver]

Determine the place and dimensions you'll be able to fit and look at what is available on vintage trailer supply and inca plastics. Inca even has a special airstream list of tanks, and tons of other shapes and sizes available. You can tell them where you want all the fittings and they'll put them in for you.
I bought my fresh water tank from OODM, wish I had just gotten one custom done from VTS or inca because of fitting size and improper number of probe connections.

[Protagonist]

Originally Posted by charlieward

Thank you. aluminum tank idea has been discarded. Any suggestions as far as gallon size for fresh and grey? In the event we change our minds and go with black water tank, how many gallons? Thanks

Gray tank equal in size to the fresh tank. Black tank half the size of the fresh and gray tanks.

The reason for making the fresh and gray tanks equal size is so that you won't overfill your waste tanks before you run out of fresh water. When your fresh tank is empty, it's time to dump your gray tank, too.

As for size, you have THREE considerations:
1 - How much reserve weight capacity does your trailer have? When the fresh and gray (and black, if you don't have a composting toilet) tanks are all full*, the trailer still has to be below its gross weight. Water weighs 8.34 pounds per gallon, so 30 gallons of water (for example) weighs 250 pounds, not counting the weight of the tank itself.
2 - How much space is available for the tanks? Obviously you can't put in bigger tanks than you have room for.
3 - How much water do you normally expect to use on a given trip? The ideal situation is to be able to carry all of the water you need for a trip, so you don't have to move the trailer just to make a water run.

Taking the LEAST capacity from those three criteria, you should be able to figure out what size tanks will work best for you.

(*You have to assume weights based on every tank being full at the same time, just in case circumstances force you to travel with full tanks all around. Overloading your axles and brakes just because your tanks can't be emptied before you hit the road is not worth the risk.)