Building a big yet robust shipping box?

So I am shipping a rare body kit for an early LS400, which consists of two side skirts and a three component rear bumper valence, from Cincinnati to Springfield, MA.

Kit for reference. Notice the cool little embossed areas for Lexus emblems in the skirt, and the big embossed "LS400" in the rear. Trés 90s. 

Greyhound is really the only shipping company that can do it for less than a bazillion dollars. Thing is, I've never shipped with them, so I don't know if they're absolute bloodthirsty savages with your items... like literally every other shipping company. 

Here's where you come in, GRM. Since off the shelf boxes this size aren't quickly/locally available, I picked up (2) UHAUL small wardrobe boxes that I'll combine to come up with the length I need. What I'm worried about though is the structural integrity of the center, and well, the entire thing. Part of me is saying, staple the boxes together, wrap everything in bubble wrap, and make sure there isn't a lot of airspace inside, should be fine. The other part of me is wanting to build a frame inside of the box with layered cardboard or PVC or even scrap wood.

Am I overthinking this? What would you do? 

I'd probably build a frame if I were concerned about it.

Does Fed Ex still provide these triangle tubes?  

The internet says they are 36" x6" x6" x6"

Big enough?  If not, maybe two boxes could be joined to make one box and then lots of tape and shrink wrap (I love big shrink wrap) to keep it all joined.  

I shipped a door for the TR250 from PHL to ATL via Greyhound.  Packed it in Styrofoam panels, wrapped it in  - big bubble - bubble wrap. Then wrapped that in card board and wrapped that with copious amounts of duck tape.   Topped that off with strapping tape - the type with strands in it.  I also made handles out of rope.  

The door is steel and pretty stout.  I would agree with Mr_Asa though.  Build a frame around it.

I received my door at ATL in excellent shape.

I worked for a heavy weight B2B air freight company for years and saw some home built containers that really left a lot to be desired.

Mr_Asa said:

I'd probably build a frame if I were concerned about it.

Yeah, that's what I was afraid of.  Right now I've got the box at the right length and figuring out how to brace it with heavy duty poster tubes, but I'm also doing the math on what this might weigh with an internal frame of 1x2s.

In reply to John Welsh (Moderate Supporter) :

I wish there was a triangle big enough. The side skirts are effectively the longest length greyhound will accept, at right around 82" long.
 

This is why I hate shipping big stuff.

My old company used to ship by Greyhound occasionally, where something big had to get somewhere quickly.  Mostly, it works.  I even shipped a rusty old original Chevy II fender to some guy in Michigan (?) and he requested shipping by Greyhound.  It was pretty inconvenient, since I had to box it up and go to the terminal, which fortunately isn't that far from me.  Took them a while (and this was waaaay before the Wuhan) but it apparently got there in one piece.

Best case scenario, it's pretty fast and pretty cheap.

If you bubble wrap the heck out of it it should be fine in any box. 

Placemotorsports said:

If you bubble wrap the heck out of it it should be fine in any box. 

That's what my far more reasonable wife keeps telling me, as I calculate lumber weight vs. building a complex network of triangular cardboard trusses.

All this for a kit that I wasn't planning on selling, and am not making much money on. Kid that wants it is over the moon though, and I just think about when I was new to the modifying cars thing and would have killed for something like this... so I want it to show up whole. 

I've had a commercial account with Greyhound Package Express that I have not used in a while.  I shipped reproduction fiberglass bumpers all over the country over a five + year span.  I would do the bubble wrap in a box and try to fill as much of the air space as possible.  Never once did I have one damaged or had to file a claim.  

When you drop it off you will see all types of things being shipped, many have little to no protection.  I've seen steel bumpers wrapped in bubble wrap and nothing else.  You would swear that this is the official shipping company of GRM, lots of old car parts.   If you think about how things are shipped you will see that they cannot pile 10 Chevy truck bumpers on your box, there is simply not enough room in the cargo space on the underside of the bus. They do not have Tetris experts trying to fill every single void in the cargo bay.  If it doesn't fit, they hold it until the next bus going that way shows up.  That's why the expected arrival date is not 100%.   Everything has to be moved by hand.  Getting stuff in and out of the bus is by hand, moving around the bus station can't be by forklift.  Carts and two-wheel dollies.

Customer service  and tracking are not FedEx.  You will not know how it is going until it is all over with.  When they say it should be there, start calling the destination bus station.  The box may sit around for a few days before they call you if you wait on them.   Most bus stations are thinly staffed and a box that is not complaining will be left alone so they can deal with the things that are complaining.  Be polite and patient and they will treat you very well.

Don't overthink this. 

In the past, I’ve used 2 large heavy-duty moving boxes from Lowes to ship a set of 4 wheels to Germany. I stacked the wheels in one box (with plenty of packing material) then slipped the other box over the top. I made sure the boxes overlapped and the flaps fit inside and over the other box. Then I taped them together with heavy-duty packing tape and did a couple full passes lengthwise too. The package ended up being 80 lbs and 60” long. The buyer said the box and wheels arrived no problem. Depending on the length you could probably stack a few boxes together in the same manner.

How about one 2x4 cut to 82" long. The only purpose of the 2x4 is so that the package can not easily be bent in two and stays rigid. 

With the 2x4 in the middle, wrap/tape the long pieces to the wood and then cover the whole thing in bubble wrap, shrink wrap and tape. 

Two boxes plus 1-2 intermediate gussets (ribs) and a bunch of bubble wrap or  packing peanuts should be fine.  
 

I would probably worry more about the pieces damaging each other than the box getting smashed. 

Go to your local independent bicycle store and get a couple bicycle boxes.    Cut to fit, and build a few standoffs.  Pack with crushed newspaper.   Most shipping companies now charge by volume, as well as weight.   Meaning, the size of your package will be be charged a weight that is much higher than your actual weight.