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Crawlspace excavation (removing dirt) from the crawlspace of a 1950 home with existing crawlspace clearance of 9" (dirt to joists' bottoms). The plan is to use "shop vacs" to provide the soil transport and cyclonic separators to separate solids from the transport medium (air).

Idea from a YT vid.

Kevin used a couple of the larger cyclonic separators in series, 3" manifolding, and three generic shop-vac style powerheads in a neighbor-friendly enclosure:

My current plan:
Dirt is collected in drums that are situated on a dumping truck. Drums are open on the bottom and restrained by straps near their tops. When the bed is raised, the drums should rotate close to parallel with the truck's bed, allowing the dirt to empty from the drums, but the drums remain strapped from the front of the bed. After lowering the bed, the drums can be placed upright again. I have enough room for around (24) drums, and I have that many stored for use.

The cyclonic separators are attached to drum lids, which can be moved to empty drum(s) as the drums fill.



The primary separator is steel and larger than the secondary separators. Almost all of the dirt will separate into its drum, and that drum will have an ultrasonic level sensor, installed in the lid, to warn when it's near full. Normally, it lights a red strobe; depending upon how reliable this sensor is, it might be used to turn off the vacuums.


Major parts
Steel Super Dust Deputy 5" Cyclone
https://www.oneida-air.com/dust-deputy/ ... -separator

Dust Deputy 2.5 DIY Cyclone Separator
https://www.oneida-air.com/anti-static- ... -separator
RIDGID 16 Gal. NXT Wet Dry Vacuum
https://www.homedepot.com/p/RIDGID-16-G ... /304795088
Infrared Dust Sentry Bin Fill Level Indicator
https://www.oneida-air.com/dust-deputy/ ... -indicator
Standard Duct Reducers
(5x3, 6x3)
https://www.oneida-air.com/steel-dust-c ... r-fittings
Suction Hose, 3" Gloxo (stiff)
3x20
https://www.amazon.com/Gloxco-Suction-T ... B0989BKCQ3

Suction Hose, 3" Powertec (more flexible)
https://www.homedepot.com/p/POWERTEC-3- ... /308005488
https://www.amazon.com/dp/B06XKQML35
3x10

Elbow, 3" 90°
https://www.homedepot.com/p/Cantex-3-in ... /202043225

Duct Quick-Change "machine adapter", 3"
https://www.oneida-air.com/3-inch-machi ... clamp-duct

Duct Quick-Change Clamp, 3"
https://www.oneida-air.com/ductwork/qui ... ocking-pin

Duct Quick-Change Elbow, 90°
https://www.oneida-air.com/ductwork/qui ... t-fittings

Duct Pipe, 3" x 10' ABS DWV
https://www.homedepot.com/p/IPEX-3-in-x ... /309282460

Duct Street Elbow 90° 2.25"
https://www.oneida-air.com/flex-hose/ad ... hose-elbow

Drum Lids, 55G (for drum bottoms)
https://seattlebarrel.com/
$10 ea. for "reconditioned" lids w/gasket.



View of drum restraint system, and one of the secondary separators installed:



Spare drums awaiting their bottoms removed:

A couple of videos from Kevin, showing his setup in action:

The vacuums have arrived. They don't come assembled, and judging from the condition of the boxes they (mostly) arrived in, they must be made of reasonably good stuff. The first one took 20 mins. to assemble, but after that only about 10 mins. ea.:
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I learned last night that common PVC is hand-formable (within reason) at the temperature of boiling water (100°C). I mated some of the Quick Change "machine adapters" (couplings) to the 3" PVC 90° elbows, using hot water, hose clamps, and leather gloves. Fun stuff! Most internet references to forming PVC use hot air guns or hot sand, but for re-forming ends (not making bends from straight sections), hot water is a lot more even and controllable, plus you can't make nasty fumes by accident using boiling water.

The couplings don't slip-fit on either end of the Cantex 3" 90°

But . . .


Dip an end into boiling water for 60 secs. (30 is not enough) and one can just hand-push the coupling into the straight end, which was a no-go fit at room temp.


The bell-end is very loose on the coupling, but after 60 secs in boiling water, the bell-end snaps back almost to its original straight-pipe dimension. From there, the hose clamps make the fit tight. Re-dip in the boiling water for a bit, then pull out, re-tighten clamps a bit, then cool with cold water.

I'll probably put a bead of silicone around where the coupling meets the PVC, but I doubt it's necessary. These fit tight.

This is interesting, I will read the whole thing at some point, but I could not get the like(thumbs up) to work today.

I guess I did get it to work one of the tries of the several I tried.

The Steel Super Dust Deputy (the large one) arrived last week. It has a 5" inlet (the one on the side), and a 6" outlet. I'm going to try feeding it via 3".



I mounted the SSDD to one side of the lid, because I think that positioning will allow the inlet 90° to be supported partially from the truck bed's side. Due to the weight of all the pipe etc., I'll likely install a brace from the lid top to the inlet area, to reduce lid deflection.



I had a 6" hole saw (lucky!).

A lid reinforcement seems like a good idea. Of course, I swung the pen at the wrong radius the first time, because math is hard.

The 5x3 reducer fits snugly on the inlet.


---

I had mounted two of the "standard size" Dust Deputies on drum lids a couple of months ago; I have two more to mount yet.

The drums are (will be) open both top & bottom. The drums sit on lids w/gaskets, but those bottom lids are not clamped to the drums.

When ready to transport, all drums will have top lids clamped in place. The idea is to restrain the drums near the top; when the bed is raised, the tops can't slide down, but the bottoms can. All drums should end up laying sideways, bottoms facing the rear of the bed.


When the drums are full, their bottoms will kick out, allowing the dirt to slide out. Empty drums don't:

I wanted (24) drums, they had to have removable lids with gaskets, and be reasonably clean. I had to drive a long way to get drums that met those conditions.

I could get another six in the back of the van.
$25/ea = $500. $76 of fuel.

I ended up reselling the red ones (contained hydraulic fluid) because they didn't have removable lids and lids have a cost; it was cheaper to buy drums already equipped with removable lids, though I did have to drain off residual coconut oil.

I'll need to remove bottoms from drums, so a "drum deheader" was acquired. This one is a Tri-Lite (Tripp Lite)/Wesco 13-216B


I need two lids for each drum. Seattle Barrel Co. sells "reconditioned" lids for about $10 ea ($240). Beware: there are two different common sizes of lids, and mine are the less-common "fruit barrel" size, slightly smaller diameter.

There must be a reason you need to do this.

I've found that there are at least three different diameters of "55 gallon drum", and naturally I have purchased one of the weirder sizes: mine are smaller dia. than "fruit barrels", which in turn are smaller dia. than "standard". I've got some lids being gathered by Seattle Barrel Company, but it's going to take them a few weeks to come up with (24).

---

Meanwhile, I finally got around to mounting the last two "small" cyclonic separators to some existing lids. A 3" hole is req'd and while I have various metal hole saws, several in the right range, none were 3" exactly, so . . . another order cycle. I use a lantern inside a drum to provide backlight, and that makes it easy to align the paper template over the 3" hole, so I could center punch for drilling the (6) 17/64" holes to bolt down the flange.

Vacuums Sequencer

As a fun side-project, I'm assembling a box that controls the four shop-vacs a bit. It'll turn them on sequentially with a second or two pause between each, and when the primary drum becomes full, an ultrasonic sensor that monitors drum fill will trigger turning them all off.

This is just slightly more complex than I like to build without some kind of line drawing, but I haven't found a good tool to do this sort of thing. Kicad will auto-adjust lines but is lousy for working with images, and Inkscape is easy to work with images but every time you have to move something, each and every line must be manually adjusted (AFAICT), so just drawing something like this took about as long as it'll take to actually assemble it.

The image below is ~13Mb, so you'll probably have to wait for it to load. Also, for full detail you'll have to select it, RMB and "Open image in new tab" or something, as the image viewer here is kind of limited in how it can display large images.




My power supply for the vacuums is a 240v 50A 14-50R extension cord from an EV charge station on-site, and a 14-50R->6-20R 4-way splitter: I have four 120v 20A 6-20R receptacles available.

This box has four 25' 12 AWG extension cords, which I cut and use for both in and out.

AC INs come in on the four cords.

• The Neutrals route up to four 30A contactors, where they're passed through to the OUTs
  The Grounds meet at a ganged feed-through terminal block, and are passed through to the OUTs

The AC Hots route through 20A circuit breakers, to the contactors, and to the OUTs.

That's all there is for the 120v side.

On the controls side, there's a 120v->12vdc power supply feeding four time delay relays (TDRs). Upon power-up, unless the drum is full, they will turn on their outputs at staged times, and the drum level sensor can turn them off via that relay on the right. The TDRs' outputs are the triggers for the contactors; I used separate, discrete power contactors because I do not trust these Chinese TDRs' 16A output rating for inductive loads like brushed motors.

The above is the meat and potatoes of the box. The rest is decoration/feedback, an ON/OFF switch, and a way to run the vacuums even if the drum level sensor thinks the drum is full: a way to bypass the drum level sensor, in case it doesn't work out, or for testing or whatever.

I'm up to around $625 on this box alone ATM. The big-ticket parts are the four extension cords, the (used) project box, and the ultrasonic level sensor.

Is this project for 'digging out' the crawl space without having to get into it and doing it by hand??

Yeah. I am too old for manual digging, and the site is on an island (though a quite large island, as these things go) so labor is crazy expensive. I wanted to buy a vacuum excavator, use it and re-sell it, but $40k is about the bottom tier for those.

I'll still have to widen the access from 26" to at least 36" (eg cut the foundation), and I'll still be laying in the crawl space guiding the 3" intake, but that's within my abilities.

The kitchen has been sinking at the center of the house for a couple of decades, and when we had to reno the kitchen floor in 2013, due to a leaking ice maker water line, we had to pull up three layers of hot (asbestos-containing) flooring. At the time, I could stick my head down between the joists and still couldn't see why the sinking, but the joists are way undersized. It was a ~1950 owner-built house with a lot of "character" built-in; mom's owned it since '73.

The plumbing is mostly galv, and it'll need to be completely re-piped at some point. So, two reasons to get more crawl space vertical clearance: room to re-pipe, and room to install joist jacks and a W-beam to support the undersized existing joists.

I should have bought a dump landscape trailer, but dump trucks are so cheap that I was going to save money and use a dumping truck instead, then sell the truck. Well, that was a bad idea, as the truck I chose was a lot worse than I'd thought, though it's sorted now. A dump trailer starts at around $6k for a dead beat-up one, and I bought the truck for $2,700, but the spreadsheet on it right now is . . . $7,300, so it'll be a net loss when I sell it on at project completion. I should have bought a dump trailer.

That is interesting. I have never seen an equipment setup like that. I'm getting long in the tooth for physical shit like that now too. This past summer I had to deal with the concrete floor in my 18 by 32 foot garage that has been unsupported over almost a quarter of it's area and split in the center to express its displeasure. i tried jacking it up and got nowhere. Finally got a company out of Kingston to drill holes in the floor and pump fill under it. That seems to have worked. I still heat with wood here and that is getting a little harder every year. So I built a wood splitter with a hydraulic table lift to make up for my decreasing strength. Life goes on!

Andy

Ooooo, I like the table lift!

I spent about half my childhood in the home I referenced. It was uninsulated and single-pane windows at the time*, and we went through ~8 cord of wood per season heating it. Handling and hand-splitting pretty much all of it, seven times from forest to stove, I swore I'd never have wood heat when I became king (of my own castle). While I've had fireplaces and wood stoves since, they've been decorative only, and we'd fire them up for ambience.

* = It got blown-in insulation and real attic and floor joist insulation around 1982, as well as almost all the windows updated to dual-pane, and fuel consumption dropped by 3/4 . . . after I no longer lived there