Texman 182g Mods

I have noticed that the bottom of the tanks (fresh, gray, and black) may have been molded flat, but the weight of the contents causes them to become curved. Since the drain is not in the middle where the curve is lowest, there is no way for the water to drain fully. One problem that may occur is that after the tank is insulated, the weight of the water will again push the center of the tank down, stressing the insulation and breaking it or breaking the bond holding it to the tank. It may need some form of support across the tank to support the center.

This same curve is why the pump can't drain the tank fully. The pickup for the water is not at the bottom of the tank, but in that projection out of the side which is above the bottom of the tank. It pulls air long before the bottom of the tank is reached.

Stephen and OG

the tank is definitely not flat on the bottom and the front is sloped as well to the middle. This is my attempt at the first layer of polyiso.  i cut the outer layer and made the insulation form closer to the actual tank form. All the stuff setting on it was an attempt to get it to "Stick" not bond to the tank.  It kinda stuck, about as good as i thought.  Duct tape covers the seams and cuts.  I had to change course on my plan.  The TPO is 60 mil and just too tough to form the tank with.  To cover the tank, it would have to make several sharp folds or bends and the stuff is just too rigid IMO to do what i had planned.  I had some heavy duty landscape fabric laying around so i decided to try that since it is tough and breathable to handle condensation. I triple layered the tank with the four ft width of the fabric and folded it all at the corners. The whole time i was doing all this i kept thinking i should of just sprayed foamed it with the closed cell.  AT this point, i could remove the whole insulation and fabric and start over even though the tank is back in the pod.  To both your points that nothing sticks to the polyethylene being true, i had planned that the TPO wrap would snug it all up and hold it together.  Since i was not able to do that, the fabric i used holds it but not too my satisfaction and the fabric would definitely absorb water if traveling in rain.  So my plan B, at this point is to use the TPO to envelope the tank and affix that to the frame surrounding the tank.  OR plan C, start over and get some foam.   BTW, getting the tank back in place covered with all that insulation and fabric was not fun or easy.  i ended up pinching a wire with one of the bolts that holds the tank.  It is still together, so i'll have to check that out now too.  The point stephen made about supporting the insulation is true as well.  That is my next step if i proceed on this path.  I plan to use pipe strap from side to side front and back of the tank and use screws to the frame to hold.

My decision at this point is to either proceed or start over. 

if i start over, i think i can remove my days work in about 15 minutes and have only residual silicone to see left on the tank that would surely be easily removed if even necessary.  Donate the insulation and duct tape to the trash.  GEt some spray foam and hope it works.  ( the crazy reviews of the small frothpacs left me concerned that i would have a mess) If that works then paint or do what ever and be done hopefully.  If i proceed i think that i have to cover what i have because of the rain trip problem and that i dont trust what i have to withstand highway speeds and the force that will generate.  that may be challenging as well

Hope this helps anyone considering this.  I knew it would be a challenge and it is for sure.  I'll post my ugly stuff as well as the pretty stuff.   post some pics next