Creating a grey tank
My little old Shadow Cruiser doesn't have a bathroom; it doesn't even have a grey tank.
What it does have is an old cut-down bicycle inner tube that dangles down from the camper wing below the sink, and I carry a 25 litre plastic container it fills.
This is OK, but not great for boondocking - what the heck do you do with a plastic tank full of waste water and the remains of last night's curry? You don't want that inside the camper threatening to spill. In the past I have resorted to climbing on the roof and ratchet strapping it down there - a risk job at the best of times. Also, I understand that in many European countries sleeping in a vehicle overnight is OK, so long as you haven't set out any camping stuff outside - such as my water tank :(
The year before last I ran into a guy with a 4WC pop-up camper at the British "Adventure Overland" show. He had rigged up his own external tank, so I decided to use it as inspiration.
Initial components:
Clearly 2 meters of 110mm waste pipe will hold quite a mass of water. So the plan was to ratchet-strap them onto the steel tie-down rails that run along the outside edge of my truck load bed. Here is an initial positional test:
At the rear end I attached the inspection end-cap, then in front of it a saddle fitting that would become the water outlet.
In the garden I found a spare length of hose which I cut down and fitted a screw connector:
I then fitted the valve. The handle on the valve was initially a problem - it would have pointed forwards with the valve closed and would have easily caught when driving through bushes or just people walking past. So I removed the handle and turned it around 180 degrees.
With the hose screwed in place I could then tuck it away behind the tow bar.
With the valve in place, which clearly needs to be vertical to fully empty the tank, I could now look at the input side. I experimented with various positions of the saddle connector. It was clear that I wouldn't be able to have the sink empty vertically straight into the tank, so I would need a hose to go between the two. So working out the best angle for fitting a hose.
It is important to remember this tank will be strapped to the truck NOT the camper, so there will be a small amount of relative movement between the two. So attaching it rigidly would be a recipe for failure.
The big problem was the lack of clearance between the tank and the camper - not enough space to have nice screw-on connectors and a length of hose snaking between the two. Attempting to insert a hose showed a further problem - it would kink and obstruct water flow.
The solution (at least for the moment) became evident by dividing the problem into two:
The first could be achieved with another section of bicycle inner tube. I used a brass adaptor to reduce the thread size from the saddle connector to the same diameter as the sink output, a diameter I know inner tube is compatible with. I applied putty tape to the thread to help seal it.
The second was tackled separately by locating some copper pipe components, leaving them slid together without securing them, and sliding the inner tube over them. The end result allows enough movement between the tank and the camper while ensuring the pipe remains open to water flow.
I initially used some copper pipe I found in the garage - later I bought some new bits (with nice smooth bends in them), but this would do to prove the concept:
I then test fitted it allowing me to position the saddle connector - notice I cannot have the connector completely vertical, but this should be fine.
Here is the tank on the ground - you can see the input and output saddle connectors and that they are not at 180 degrees from each other:
I then fed the copper tubing inside the inner tube:
I then drew back the ends of the inner tube so I could wiggle the inner copper tube into place between the camper and the tank. Once in place I could pull the inner tube ends down and secure them.
Notice I cut a section of inner tube with the valve stem still in it. I thought this might be useful to release airlocks. I considered fitting a breather on the tank, but decided that before I did that I would test the tank in practice. If it worked without a breather it would be one fewer hole I had avoided drilling in the pipe (once drilled holes cannot really be un-drilled).
I found an old cheap pair of ratchet straps, cut the hook and webbing off one end and cut a short section of webbing that I then doubled up and ran around the pipe:
The first trial of this was a short camping weekend in Marlborough. This indicated a couple of problems:
The first problem was because although the tank was ratchet strapped to the load bed rail in the same way front and back, at the back the saddle connector pressed against that rail causing that end to be lower.
The second problem was more major. I tried opening the cap on the valve stem on the inner tube. That helped a little, but it was clear a proper tank breather was definitely required.
Hunting around at home I found a spare high pressure air connector. I drilled a hole in the top centre of the tank and screwed it into that hole, having sawn the connector's thread short enough so it didn't protrude too much into the tank. The more it protruded into the tank the earlier it would be blocked by rising water. I considered where to fit the breather, but elected to put it in the middle. If fitted to one end or the other then as the water surges from one end of the tank to the other during driving it would undoubtedly form a little fountain out of the breather. With the breather in the middle this was less likely.
Next step was to level the tank. You can buy clip-together brackets designed to hold these 110mm pipes against the wall. I purchased one of those and found a spare piece of timber about 40mm thick, sawed it down and screwed it to the bracket. This forces the tank to stand off from the bottom of the camper. The bracket isn't actually screwed to the camper, just acts as a spacer:
This brought the tank into level. Maybe over Easter I'll paint it now I have proved it works.
At our next 4x4 weekend we used the camper again and were delighted to find the sink now emptied as if the tank weren't there, thanks to the breather.
Looking forward to testing this out further later this spring.
Steve.
What it does have is an old cut-down bicycle inner tube that dangles down from the camper wing below the sink, and I carry a 25 litre plastic container it fills.
This is OK, but not great for boondocking - what the heck do you do with a plastic tank full of waste water and the remains of last night's curry? You don't want that inside the camper threatening to spill. In the past I have resorted to climbing on the roof and ratchet strapping it down there - a risk job at the best of times. Also, I understand that in many European countries sleeping in a vehicle overnight is OK, so long as you haven't set out any camping stuff outside - such as my water tank :(
The year before last I ran into a guy with a 4WC pop-up camper at the British "Adventure Overland" show. He had rigged up his own external tank, so I decided to use it as inspiration.
Initial components:
- 2 meters of 110mm diameter drain pipe
- One rubber end cap
- One end cap with screw-off access plate
- Two saddle fitting connectors for external fittings
- One valve
Clearly 2 meters of 110mm waste pipe will hold quite a mass of water. So the plan was to ratchet-strap them onto the steel tie-down rails that run along the outside edge of my truck load bed. Here is an initial positional test:
At the rear end I attached the inspection end-cap, then in front of it a saddle fitting that would become the water outlet.
In the garden I found a spare length of hose which I cut down and fitted a screw connector:
I then fitted the valve. The handle on the valve was initially a problem - it would have pointed forwards with the valve closed and would have easily caught when driving through bushes or just people walking past. So I removed the handle and turned it around 180 degrees.
With the hose screwed in place I could then tuck it away behind the tow bar.
With the valve in place, which clearly needs to be vertical to fully empty the tank, I could now look at the input side. I experimented with various positions of the saddle connector. It was clear that I wouldn't be able to have the sink empty vertically straight into the tank, so I would need a hose to go between the two. So working out the best angle for fitting a hose.
It is important to remember this tank will be strapped to the truck NOT the camper, so there will be a small amount of relative movement between the two. So attaching it rigidly would be a recipe for failure.
The big problem was the lack of clearance between the tank and the camper - not enough space to have nice screw-on connectors and a length of hose snaking between the two. Attempting to insert a hose showed a further problem - it would kink and obstruct water flow.
The solution (at least for the moment) became evident by dividing the problem into two:
- A waterproof tube with connections either end sealed to the camper at the top and the tank at the bottom
- Some structure that would prevent kinking and therefore blocking of the pipe
The first could be achieved with another section of bicycle inner tube. I used a brass adaptor to reduce the thread size from the saddle connector to the same diameter as the sink output, a diameter I know inner tube is compatible with. I applied putty tape to the thread to help seal it.
The second was tackled separately by locating some copper pipe components, leaving them slid together without securing them, and sliding the inner tube over them. The end result allows enough movement between the tank and the camper while ensuring the pipe remains open to water flow.
I initially used some copper pipe I found in the garage - later I bought some new bits (with nice smooth bends in them), but this would do to prove the concept:
I then test fitted it allowing me to position the saddle connector - notice I cannot have the connector completely vertical, but this should be fine.
Here is the tank on the ground - you can see the input and output saddle connectors and that they are not at 180 degrees from each other:
I then fed the copper tubing inside the inner tube:
I then drew back the ends of the inner tube so I could wiggle the inner copper tube into place between the camper and the tank. Once in place I could pull the inner tube ends down and secure them.
Notice I cut a section of inner tube with the valve stem still in it. I thought this might be useful to release airlocks. I considered fitting a breather on the tank, but decided that before I did that I would test the tank in practice. If it worked without a breather it would be one fewer hole I had avoided drilling in the pipe (once drilled holes cannot really be un-drilled).
I found an old cheap pair of ratchet straps, cut the hook and webbing off one end and cut a short section of webbing that I then doubled up and ran around the pipe:
The first trial of this was a short camping weekend in Marlborough. This indicated a couple of problems:
- The tank was not level, so this would clearly limit its capacity
- The tank didn't require much liquid before it airlocked and the sink would not empty
The first problem was because although the tank was ratchet strapped to the load bed rail in the same way front and back, at the back the saddle connector pressed against that rail causing that end to be lower.
The second problem was more major. I tried opening the cap on the valve stem on the inner tube. That helped a little, but it was clear a proper tank breather was definitely required.
Hunting around at home I found a spare high pressure air connector. I drilled a hole in the top centre of the tank and screwed it into that hole, having sawn the connector's thread short enough so it didn't protrude too much into the tank. The more it protruded into the tank the earlier it would be blocked by rising water. I considered where to fit the breather, but elected to put it in the middle. If fitted to one end or the other then as the water surges from one end of the tank to the other during driving it would undoubtedly form a little fountain out of the breather. With the breather in the middle this was less likely.
Next step was to level the tank. You can buy clip-together brackets designed to hold these 110mm pipes against the wall. I purchased one of those and found a spare piece of timber about 40mm thick, sawed it down and screwed it to the bracket. This forces the tank to stand off from the bottom of the camper. The bracket isn't actually screwed to the camper, just acts as a spacer:
This brought the tank into level. Maybe over Easter I'll paint it now I have proved it works.
At our next 4x4 weekend we used the camper again and were delighted to find the sink now emptied as if the tank weren't there, thanks to the breather.
Looking forward to testing this out further later this spring.
Steve.
