Our next rig

[avanti]

IMG_5759.jpeg
IMG_5763.jpeg
IMG_5867.jpeg

At some point, they strip everything back to the raw van and do the plumbing, cut holes, and other rough-ins.

All these pictures are arranged in chronological order. They show how they build out significant segments of the interior, and then repeatedly remove them to do infrastructure work and to make modifications as necessary.

When everything is finalized, they once again remove everything and apply the veneers and other finishes:

IMG_5875.jpeg
IMG_5926.jpeg

At first, I thought this was crazy (it took me awhile to realize that much of the early "mockups" would survive into the final van.) They make skillful use of both CNC and manual craftsmanship to evolve a final design in many small steps. Many times during visits, we would say things like "that radius isn't quite right, and they would revise it in a few minutes. It sounds wasteful given the quality of the materials being used, I have concluded that it isn't. More often than not, the changes were simply applied to the existing piece, rather than discarding it. And when a new piece was needed, the old piece was most often simply reused for some smaller component. It was all quite impressive.

[@Michael]

This has been a highly informative thread.

I'm looking forward to more information on your van automation.

[GeorgeRa]

Thanks for sharing, it seems as you squeeze a practically full proto into your development process, expensive but likely well paid off by less mistakes in the final product.

Did you weigh cabinetry while building this plywood prototype or calculated weight from CAD?

[avanti]

Originally Posted by GeorgeRa

Did you weigh cabinetry while building this plywood prototype or calculated weight from CAD?

I just trusted the upfitter on this one. This is the highest capacity available Transit (GVWR 11,000lb, max payload 4,870lb). Should be plenty of headroom, but I haven't weighed it yet.

[Viperml]

Avanti, I thought you would have built your rig yourself but to that of course was a few years ago lol. I like what you have posted about your rig being built. Can you post final pictures of what it looks like or are they posted somewhere else? I would be interested

[avanti]

I know that this thread has been quiet for awhile. I still have a lot to tell, but I have been so absorbed in executing various planned improvements to the van (mostly automation-related) that I have lacked time and energy to document here. Won't go on forever.

There is one dangling topic that I can now address though: What is happening with Creative Mobile Interiors. I previously mentioned their change of business model, but couldn't talk about the non-public details. I have finally found a public announcement of this information, so I can now share what I know:

What happened is that CMI (which has always been a medium-sized custom upfitter) has been acquired by Airstream:

[Airstream] provided an overview of the 2025 model year changes, which will be released publicly beginning Aug. 2, as well as several company updates including changes to its Airstream Exclusive store model, restructuring of key leadership positions, and the strategic acquisition of Creative Mobile Interiors, a Columbus, Ohio-based customizer that will help the OEM produce limited edition runs on products in partnership with national brands.

https://rvbusiness.com/wheeler-airst...ness-as-usual/

CMI has always done a lot of customization on Airstreams of all shapes and sizes, so they are well-familiar with the platform. They have directly collaborated with Airstream in the past, and I get the impression that Airstream would frequently refer customers to them when custom work was needed.

My understanding is that this was happening frequently enough that Airstream decided that it made sense for them to acquire the company. This will permit them to directly address low-volume and specialty rigs, which have always been CMI's forte. My impression is that the acquisition has been light-touch so far from a management perspective, and not a lot has changed, at least for now. I do not know whether they are still permitted to take non-Airstream work, but it you have a need, it might be worth a call.

[avanti]

Originally Posted by avanti

The exploded drawings show internal anti-slosh baffles and also heating tubes which connect to the anti-freeze glycol loop. The tubes are continuous with no internal fittings, so I am comfortable with the safety, although I am mulling over switching to propylene glycol just for the extra safety.

Originally Posted by Arlo

Very interesting, I’ve never seen custom tanks like that with internal pipes for the glycol loop. While the probability of a leak is no doubt very low, I can relate to considering the use of polypropylene glycol in the loop.

So, I got around to swapping out the ethylene glycol and replacing it with propylene glycol. Had to do quite a few water flushes in order to clear all traces of the ethylene. Probably would never had been an issue, but now I have one fewer thing to worry about. Safety first!

[booster]

Originally Posted by avanti

So, I got around to swapping out the ethylene glycol and replacing it with propylene glycol. Had to do quite a few water flushes in order to clear all traces of the ethylene. Probably would never had been an issue, but now I have one fewer thing to worry about. Safety first!

No argument on the safety difference as it is a major consideration, but you probably are aware of the lower heat capacity of the propylene glycol compared to ethylene glycol.

I don't recall the exact amount difference, but back 25+ years ago when there was a big push to switch motor vehicles to propylene glycol, very many of them had overheating issues because of that difference.

In a cooling or heating loop, you may or may not have enough capacity that it is not an issue, but you may need to either cut down the heat input to fluid by turning down the burner or heating element, or be able to vary the flow rate of the fluid to get back into good balance.

Propylene glycol works just fine if everything is designed to work with it in the system. Several places I worked at used it in heating of heat transfer fluid for thing like heating the molds in rubber molding or the laminating presses for printed circuit board. Almost all cooling towers use propylene glcyol also, I think.

[avanti]

Originally Posted by booster

No argument on the safety difference as it is a major consideration, but you probably are aware of the lower heat capacity of the propylene glycol compared to ethylene glycol.

I don't recall the exact amount difference, but back 25+ years ago when there was a big push to switch motor vehicles to propylene glycol, very many of them had overheating issues because of that difference.

In a cooling or heating loop, you may or may not have enough capacity that it is not an issue, but you may need to either cut down the heat input to fluid by turning down the burner or heating element, or be able to vary the flow rate of the fluid to get back into good balance.

Propylene glycol works just fine if everything is designed to work with it in the system. Several places I worked at used it in heating of heat transfer fluid for thing like heating the molds in rubber molding or the laminating presses for printed circuit board. Almost all cooling towers use propylene glcyol also, I think.

Yes, I'm aware. We'll see, but: (a) the Espar heaters continuously monitor both the input and output coolant temperatures and modulate themselves accordingly; (b) as far as I can tell, I have plenty of heat budget. Worst case should be somewhat longer duty cycles; (c) the glycol pumps in both loops have two speeds, and I have been doing fine on low. Ethylene glycol actually has a higher specific heat. The problem is that it has higher viscosity, making heat transfer less efficient. If necessary, I can raise the pump speed to compensate. The pumps are virtually silent at either setting; and (d) I have installed temperature sensors at all important points in the loops, so it should be immediately apparent how things are behaving.

[GeorgeRa]

I use propylene glycol in my Espar/Isotemp water heating system, works great but I don't have comparison data to ethylene glycol.