CUSTOM HITCH CARRIER FOR THE AIRSTREAM INTERSTATE, PART 2: OUTSIDE THE BOX

I tried - I really, really tried! - to find an off-the-shelf solution for carrying either our original Yeti Tundra 50 cooler, or a replacement cooler, on the rear bumper of our Airstream Interstate.  Some of that agony is described in this recent Air Forums thread, and other parts of it are on different threads still, including this inaugural discussion from almost two years ago.  And even more agony is described in Part 1 of this post.

A wing, a prayer, and an over-stuffed mini-van that became the inspiration for our September 2014 Airstream Interstate purchase, for we drove that floggin' mini-van on a 6,000 mile trip earlier that same year.  While a mini-van may suck for long-haul comfort and convenience, it sure swallows a Yeti cooler with ease.  Which is very much unlike an Interstate.

Here's a key piece of information, though:  That Yeti you see above was packed with water ice and thus could be safely stored inside the mini-van.  The same would not necessarily be true if it had been stuffed with dry ice, which off-gasses carbon dioxide that could potentially displace oxygen and create a safety hazard. 

To make a painfully long story short, no existing exterior carrying product met our needs.  Or, if something did show potential to meet our needs, it was either:

(a) too heavy given our GVWR restrictions
(b) not yet in final design, let alone production, and thus not readily available commercially
(c) not sufficiently engineered to be as durable or as secure as we needed (pretty much every mass-produced hitch carrier fit that description)
(d) scandalously expensive if it was sufficiently engineered, or
(e) some combination of the above.

Do you see that custom bumper upfit in this pic chosen at semi-random from the internet?  This one is carrying a spare tire, but an apparatus to carry a cooler would be constructed in a similar fashion.  This thing is gorgeous, it's superbly engineered, and it's as heavy as hell.  Two out of three ain't bad, but we needed something lighter.  

As the old saying goes, if you want something done right, you have to do it yourself.  And so we did.  Here's the sequence of steps involved in the production of our custom hitch solution.  As usual, I'm giving general descriptions only here, and if someone wants greater specifics, please feel free to email me and we can discuss.

The journey started with a trip to a local steel supply shop to pick up the raw materials, which they were sizing down for us in this photo.  

My brilliant husband designed this apparatus with the intention of minimizing weight while maximizing strength, durability, and security.  It started with the frame of a shallow tray into which the Yeti could be placed. 

Bottom braces were then cut and welded into place. 

It was slow going with plenty of rest and water breaks on this fabrication effort, as late June temperatures climbed toward 100 degrees.  

Art shot of raw materials - I insisted on buying an itty bitty Texas embellishment, about 3 inches across. 

Did I mention that it was almost 100 degrees?  As hubs did the welding - in cargo shorts despite the sparks flying everywhere - I watched in amusement from the relative comfort of the Interstate where I ran the A/C, mounted the Reflectix window covering keepers, and templated the cab for a custom weather mat overlay (no blog post to come because that project turned out to be a total failure).  I think I got the better end of that deal, although I did trip breakers about ten times trying to keep the Interstate cool by shore-powering it into a regular household circuit (hubs had dibs on our 220 circuit for the welder).  

From this pic you can start to get a feel for how this hitch carrier was engineered to be different from most other products on the market.  See that square tube cross piece that has been inset into the Yeti frame?  That is part of its extra strength.

Here's another view of the Yeti in its proto-hitch tray.  Note how this is shaping up to be much smaller and lighter than a conventional hitch platform or basket.  It only has to be large enough and heavy enough to get the job done safely.  

As for the positioning of this Yeti carrier relative to the rear end of the Interstate, that was determined by trial and error.  I knew I had to compromise on this design - originally I had wanted a swing-away arm so that I could keep a cooler back there and still open both rear doors.  But I had to meet practicality half way and adjust my expectations such that only one of the two doors could be opened at all times without restriction (that much was non-negotiable).  If I need to open both doors at some destination, then I will simply have to drop the cooler to the ground for the evening and tether it with a lock - no big deal.

Husband and I settled on this configuration - the Yeti centered on the port rear door, and a large platform which will serve multiple purposes on the right, as outlined in cardboard (we don't do anything around here without first mocking up out of cardboard).    

The back door on the passenger side is the one with the door handle - that's why it was chosen as the one to be open-able.  And the large platform underneath it will serve as:

(1) a generous step (much better than the tiny hitch step I'm currently using)
(2) an exterior seat (it's the perfect height)
(3) A small table or staging platform if no picnic table is present at a location, and
(4) a potential lashing point for general cargo that doesn't require the same magnitude of structural support as a loaded Yeti 50 cooler (I'm thinking perhaps a future inflatable kayak in a stuff sack).

This photo shows the hitch connector being positioned with support plates that were later welded into place. 

After everything was welded up, both my husband and I spent quite some time grinding and polishing all those welds.  The point was not to make it look flawless but to prevent future cuts and scrapes from burrs as we were handling it.  This was my husband's first major welding project and I could see his skill growing each day that he worked on it.

Now, on the issue of the cooler itself, I was initially very skeptical that it could be attached securely, given that Yetis are such high theft targets.  We took a two-fold approach to addressing that risk.

My husband welded two heavy steel bars that will extend down through the Yeti's security ports (the bars are 3/8" by 5/4" and weigh 2.5 pounds each).  They will lock to the hitch apparatus individually in a way that will make removal extremely difficult, certainly with enough robustness to thwart the typical smash-and-grab theft scenario.  At the same time, they will prevent the cooler from bouncing off the shallow tray as we go over bumps.  This approach kills two birds with one stone - security and stability.  

Additionally, I made the Yeti itself a much less desirable theft target by defacing it utterly.  I spray painted my phone number, emblazoning it across the entire width of the cover.  And I also added various stickers and patches, some with industrial-strength adhesive.  Nobody will ever be able to steal and fence this thing as a virgin untraceable cooler.  It is now ruined for many theft purposes.  

This minimalist hitch apparatus ended up weighing 57 pounds - significantly lighter than many of the other options we identified in the commercial market.  Either one of us can get it on and off the hitch without assistance (although in my case, there may be some cuss words involved).

After many rounds of welding, the moment finally came when it was ready for me to de-grease, prime, and paint.  Notice those two key-hole slots on either side of the Yeti (open) side of the apparatus.  Those are where the security bars come down to be locked in place.

Oh, and see all the little rings welded on the side?  They are there in case we have to lash cargo to it.  Now that we have this base apparatus completed, in the future we can fabricate additional accessories to fit the needs of a particular trip.  Perhaps a bike carrier insert, for instance, if we need bikes but not the cooler.  

Most if not all jurisdictions require rear license plates to be illuminated, and we addressed that by fabricating a bracket that will accept a light that wires to the hitch's existing electrical pig tail.

Spray painting in action.  Square tube was used for the bottom of the bracket so that it would stand out about an inch and a half from the front of the Yeti cooler.  That allows for easy placing and removing of the cooler (it's not too tight a space).  This because the Yeti blocks the original door mount for the plate.  

Incidentally, it wasn't lost on us that we created an apparatus that was so unique and custom that it may end up being a more desirable theft target than the Yeti cooler it was originally intended to secure.

Ooooh la la!  Sexy!  Some women model swimwear - I model Pewag security chain.  Arm for scale.  

I procured this Pewag chain so that I could supplement the hitch pin, as some of those can reportedly be defeated using a sledgehammer even if they are the locking type.  I'm not going to publish how I used this, but if anyone wants to discuss, feel free to email me.

And now for the great reveal, aka the money shot:

Smiling dog mirrors owner's mood.  

We will be adding a bed liner traction coating to the step / seat / table portion of the apparatus to make it non-slip.  I will also add some DOT C2 reflective tape to the trailing edge, because when the cooler is not in place, it's difficult to see from a position behind the interstate.  I'll do that after the bed liner product is applied.

Minimalist.  Streamlined.  Wonderful.  Looks like the Interstate was born with it already there in place.  But from a practical standpoint, it needs more visibility so that other drivers do not accidentally get too close.  

I will also be crafting an insulating and waterproofing slip-on cover for the cooler; all that spray paint and sticker defacing helps to discourage theft, but it needs to be covered during severe weather, including the heat of our summer.  (EDIT:  Those trim-out elements are described in Part 3 of this series).

Last but not least, the most efficient way I deduced to handle carbon dioxide overpressure in the Yeti cooler was to buy a couple of extra drain plugs (West Marine has two for ten bucks) and drill a small hole in the one that is intended for use with dry ice.  The intact plug will be reserved for use with water ice.

Just a small hole, because Yetis are well-known for being air-tight, and according to internet reports, a great deal of pressure will build up in the cooler.  This was a better way to deal with the situation than piercing the cooler itself, which would have been a non-reversible decision.  

One more shot of the pooch, who was thoroughly bored with my photo shoot by the time this one was taken.

"Yeah, whatever.  It's time to get over yourself and feed me."

For those readers who are not familiar with the construction of Yetis, her butt is right up against one of the two steel bars that extends downward from the lid and locks beneath the apparatus. 

Thanks for reading.
:-)

One day soon, it won't be my driveway that I'll be sitting there staring at.  It will be the next million dollar view.