Expo-Lite

[OlympiaFJ60]

Very cool. I too like the idea of using the boxes. Was the top rail on already on the boxes? Looks like the tongue box is the perfect width.

 

[REasley]

The tongue box is about 3/4" wider than the other 2. So at 3/8" on each side it won't be noticeable. All 3 are stock boxes. I had the mfg. add the rail and increase the gauge of one box.

 

[R_Lefebvre]

I would have loved to have done the frame in aluminum. I just couldn't convince the wife that I really did need a spool gun.

Better to ask forgiveness, than permission!

 

[indiedog]

Are the two aluminium boxes joined together in the middle somehow to achieve the monocoque structure? I imagine there is a gap of some sort to allow the lid on the top opening box to clear the other. If so there will be a lot of bending on the 4 cross members in the centre area, especially if that water tank is full. Is it worth adding some alum sections to the front and back ends of the boxes to join them together?

 

[REasley]

indiedog
The boxes will be joined back to back with VHB tape and stainless steel nuts & bolts. The top opening box is notched at the back allowing the lid to open without hitting the other box. The rails are also offset to bypass when the lid is open.

 

[compactcamping]

Ok, you've peaked my interest on the VHB tape. For 46k rated tape (in shear), what is the compression and tension rating?

 

[REasley]

compactcamping
http://multimedia.mmm.com/mws/mediawebserver.dyn?6666660Zjcf6lVs6EVs666yacCOrrrrQ-

4941

 

[REasley]

Finally figured out how I wanted to do the tank. I drilled to bolt 3/16 flat stock across the tank, but realized it would be hard to tighten or adjust the steel straps. So... I welded the holes shut and added tie down hooks in their place. The nylon tie down straps have a working load of 1000 lbs and a breaking strength of 3000 lbs. That should hold it.
Here it is upside down

 

[elcoyote]

I think you may find that your tank will not stay tight and come loose with the nylon straps. I would be horrible to loose the tank on the trail due to strap failure caused by abrasion.

 

[REasley]

I gave this issue a lot of thought and could not come up with a better solution. The polyethylene tanks don't like vibration and bare steel. A number of companies use similar straps for securing spray tanks without abrasion issues. That being said I have never seen anyone support a tank with this type of webbing, so I am venturing into the unknown. I have used this style straps for a number of years and have not had stretch problems. The ratchets will allow for adjustment. You might be right, it may fail. But I will watch carefully and adjust accordingly.

 

[JamesDowning]

You may want to add more stitching to the hook stitching on the straps, and then add some sort of leather chafe guard between the straps and the tank.

Also, is the tank internally ribbed? If not, you may get some budging and higher loads at the center strap.

 

[REasley]

This should solve the potential abrasion problem.


The points of contact are isolated with a wee bit o skived side leather. The rest of the strap has only casual contact.

 

[JamesDowning]

Nice! Are the corner chafe guards held in place by any stitching? They may have a tendency to wander on ya due to vibrations. If you know that's where they should stay you might as well make it somewhat permanent.

 

[REasley]

Yah they might move. If they do, I'll dab them with a little rubber cement.

 

[gabepari]

Plan on replacing those straps quite often. You'd be surprised how fast the nylon will deteriorate when left under constant tension. My main concern would be where the strap is looped around the tie-down hook. There are lots of better ways to mount a tank that won't weigh much more than the ratchet straps.

Gabe