It's not 80x markup vs a commercial airliner soap dispenser. It's 80x markup vs a janitorial supply store soap dispenser. That is very easily identified as a Bobrick janitorial supply #B-88216. https://www.globalindustrial.com/p/bobrick-20-oz-liquid-loti... Home Depot carries that brand but not that specific dispenser.

It would be illegal for anyone to install that in a commercial airliner without testing it to show compliance with the federal requirements, and I just about guarantee that it would fail some of that testing, specifically flammability. (I actual at one point DID work for Boeing doing interiors flammability cert testing, back in the 2000-2002 timeframe but got hit by the post 9/11 layoffs.)

Likely the design differences are just some minor venting/check valve provisions to ensure it does not spill soap when subject to rapid pressure changes and unusual attitudes such as zero G, and it has been shown not to freeze and burst if they thermal cycle the airplane down to -20F. The most critical design difference is that the very clearly polyethylene soap reservoir on the industrial model is a fire hazard in a commercial aircraft and would never be allowed for ANY interior component because it is not self-extinguishing, in fact it burns like a candle. So you are going to have to make the reservoir of some type of fire-resistant engineering plastic with fiber reinforcement, like Lytex or something similar, and have some tiny mom and pop machine shop make it for you in small quantities for a large amount of cash, because they have a mortgage to pay too.

But then you are going to have do do all kinds of testing, testing that sounds like it should be cheap, quick and easy... but is actually very expensive, slow, etc for needless bureaucratic reasons, to demonstrate to the government that it meets the standards that they levied on the procurement contract. Note, not demonstrate that it is a good product.... just demonstrate that it meets the contractual requirements, however sloppily or arbitrarily they were written.

And that's all just to sell a spare soap dispenser for a global fleet of 275 aircraft, and somehow eke out a profit on it, as Boeing are supposedly not doing this for charity. And all those paperwork shufflers need to be paid, they all have mortgages too.

If the Air Force wants to waive their own requirements and install an untested and undocumented soap dispenser from a janitorial supply store in their airplane, instead of buying one from Boeing, they are free to do so. No one is stopping them. They make all kinds of parts on their own, actually. It's not against any law, it is not a certified aircraft. It's is their air crew's safety that is on the line, and trust me, the Air Force cuts safety requirements in FAR more critical areas than lavatory soap dispenser reservoir flammability.

But it is disingenuous to compare the cost of a product that does meet the requirements and has been documented to do so, with the cost of a product that does not meet the requirements, from an unknown source.

Here are some good examples on the civil commercial side. Say I wanted to install a 12 volt cigarette lighter socket in my little Cessna Skyhawk. Could I install this nice stainless steel one from the boat store for $15? https://www.fisheriessupply.com/sea-dog-line-stainless-steel... No I could not, that would be illegal, I would have to buy this $100 one. https://www.aircraftspruce.com/catalog/elpages/cigrecept.php... It is physically the same part, made in the same factory, but Lone Star Aerospace has done the testing and paperwork to convince the FAA that it meets their requirements, and they have put a sticker on their version to prove it.

Cessna charges over $2000 for a P/N 6508092-1 pump that is used for windshield de-ice on Citation jets and as a fuel pump on smaller planes. If you peel off the Cessna sticker it is a Facet P/N 476088 fuel pump that was used on Massey-Fergusson farm tractors, and you can buy one at NAPA auto parts for $100. McFarlane Aviation buys the same pump, does some testing and paperwork, puts a new nameplate on it and sells a certified alternative to the Cessna one at the bargain price of $380. Replacement parts for the Air Force are put out to open bid. If someone thinks they can meet the bid requirements and make a profit at it with a cheaper offering, they are free to do so.

But before you think you can make EZ money buying Home Depot soap dispensers, testing them, and selling them to the Air Force at a profit, I suggest you read the short cautionary tale of "The TSO'd Pencil", in which the hero protagonist quests to earn a profit buying pencils for 5 cents each at selling them as Certified for $13.85 each, in packages of 10.

http://www.rstengineering.com/rst/articles/tsodpencil.pdf

I has always thought of this as merely an apocryphal tale, but I recently had to buy Certified Pencils, AND have them conformed by an FAA inspector for a test, I poop you not. They actually exist. They are now $16 each or $218 for a package of 17. https://www.gardco.com/Products/Hardness-Testers/Scratch-Har...