Rolling oil drain pan for home shop mechanic's pit

[MinnesotaDave]

Of course you should.

x2

[N2 Welding]

Should I add pit construction photos and story to this thread?

Absolutely.

[ronsii]

Oh!!! come on guys.... pics are overrated anyways nothing compares to a nice detailed description of the process you went through to complete your pit and that way we can imagine in our own minds eye what your job looked like

[12V71]

That would be the pits without pics...

[N2 Welding]

That would be the pits without pics...

Just Pitiful

[12V71]

Just Pitiful

Beware of pitfalls in punny situations.

[N2 Welding]

Beware of pitfalls in punny situations.

OMG LOL

I think I need to make a pit stop now.

[kb0thn]

The pole shed was built in the 1980's. The owner who had it built lives half a mile away and says it wasn't filled. But the (younger) farmer who farms the land surrounding us says that it was built on fill. From the excavation I have done for the other shop in the building, I know that the soil is hard packed clay. And it has been kept dry for 35 years. I can put 5 tons on a jack stand and it won't leave a mark. So my goal in excavation for the pit was to overdig as little as possible and disturb the surrounding soil as little as possible. I wanted 6" over room on the sides that I could backfill with flowable fill. I decided to use ICF walls so I would need to get back in to strip wall forms.

Pit was originally going to be 16' long and the finished floor of the shed was going to be 6ft above the floor of the pit. The inside width is 42". I ended up downsizing it to ~14ft long. The ICF walls chew up 11.25" on either side. Plus 6" overdig on all dimensions requires a hole 16 x 6.5 x 6.5 ... or 676 ft^3 ... or 25 yd^3.

I have a backhoe on my compact utility. It looked like it would have barely enough reach. But I am generally morally opposed to renting machinery, so I decided to forge ahead.

Cleaned out just enough area to work (stupid):


Laid it out:


Got my 6 year old son to dig:

[kb0thn]

Backhoe kind of ran out of reach. If I had cleared more area around it, I could have endless re-position it and done it. But it could really only reach 7ft in a 2ft^2 area:


So I decided to dig a ramp and drive the skid steer in.


That was a little nerve wracking. Doesn't look like much from the photo. But my ramp was steep and the machine is completely underground when in the bottom of the hole.

[kb0thn]

But it worked and I was able to square up the hole and flatten the bottom. Touched up the ramp end with the backhoe. And had to do a little hand cleanup. The clay is so hard that a pick axe just bounces off. So used clay spade on big hammer drill to peel off the clay:


With hole dug, I got my beautiful wife to clean up the excavation and set the form for the floor. Did a simple form that would allow the concrete guys to just screed off the form. Slab thickness varies from 6" to 16". Average thickness of 10".


Concrete guys poured the floor while I was out of town. They took it upon themselves to add some 2x4s to make a notch for the walls to key on to. Which I didn't want. Because then they didn't actually screed the whole floor. In fact they didn't finish outside of the notch at all. Which is a big pain with the ICF because they want to sit on a flat surface.

[kb0thn]

Their stupid keyway 2x4s caused problems. They didn't put any release agent on them and they didn't pull them right away. Which pisses me off to no end. There was literally 50 gallons of used oil sitting 25ft away. And 100 gallons of diesel sitting 100ft away. I ended up spending about 3 hours getting the keyway forms out piece by piece. And spalling the concrete around them in the process.


But after much work, ended up with something good looking to build on.

[kb0thn]

I used FoxBlocks "Reveal" hard faced ICF. They have a removeable plywood inner face. Unfortunately they only come in straight pieces, so the were 10x the amount of effort to use as normal FoxBlocks. Lots of cutting. Here is the first little bit that kind of gives a good cut-away view:


Added lots of vertical rebar. And there is a loop of horizontal rebar at each course.


Ready for internal bracing:

[kb0thn]

Internally braced. Used ratchet straps so I could adjust it. Normally there are adjustable ICF wall braces used. But I didn't have any and I didn't have any room for them. So a couple hundred dollars of lumber and screws and ratchet straps were used.


Concrete showed up and concrete guys put together a little chute from scrap wood.


I continuously adjusted the bracing down in the hole.

[kb0thn]

Got the walls poured.


Time to strip forms. My son is a very good helper. We removed thousands of screws. About a 5 gallon bucket worth.


My layout allows the pit to be used on one side of the main door while still allowing enough room between shop and pit for another vehicle. Tested that repeatedly with concrete trucks (including one who hit the shop and took out a door). And tested it when I brought home a lathe.

[kb0thn]

I stubbed in lines for air intake, air exhaust, electrical, sump pump, and a sleeve for compressed air line:


Then encased it with flowable fill. Flowable fill is a low strength concrete. I used it between the ICF walls and the excavation and over the top of the lines.


It took a lot longer to set up than I expected. Maybe 24 hours before it felt firm. It was easy to trim the extra off just with the bucket on the skid steer. But it did a great job of providing protection for the lines for the further work and will provide a good bearing surface for the slab on top.


More information on the air and utilities in my thread on Practical Machinist:
https://www.practicalmachinist.com/v...lation-382543/

[kb0thn]

I did a formed steel rim that joins the pit walls to the main slab. It has a 6" ledge for cover / rolling things to sit on. It is 1/4" thick steel. My 60 ton press brake will only so 4' of 1/4" steel, so I had the steel service center brake it for me. First time having them form anything. Material, bending, and delivery was $500 for 1000 lbs. Seems like a deal to me. And similarly, my big CNC band saw was 1/4" too small to cut the miters on the formed pieces (good planning there!). So had the neighbors shop do it on their band saw. They did a bunch of cutting for $150. Those big miters across the formed profile aren't real easy to cut. I was happy with the money I spent subbing those two jobs out.

I glued in threaded rod around the perimeter of the pit to support the rim as I built it.


The concrete contractor took a vacation in the middle of the job, so I hired one of his laborers to help. He is an experienced weldor and had more time than I did. So we fit it together and then I had Pat to the welding and grinding.


Pat's weld. Done with a little Millermatic 180 MIG welder. No idea the settings. Probably running wide open.

[ronsii]

Nice!!! an uphill...downhill weld

[kb0thn]

Turned 304 stainless steel sockets for a railing around the perimeter. They accept a 3/4" pipe in the socket. And then underneath they have a 3/4"-10 female thread. In case I want to tie something down. Or whatever. Scrap stainless and an hour or two on my CNC lathe.

Mag drilled 1/16" oversized holes for the sockets. Of course the corners had to go right through the weld, which wasn't awesome with cheap Amazon HSS annular cutters:


TIG welded in the sockets using 309L and my Miller Syncrowave 180. I only have a foot pedal for it, so was fun running that on top of the ladder.


Flying the welder to work. Always a project. Had to extend the power cord on it. And then get it over the top of the PEX tubing.

[kb0thn]

Concrete contractor showed back up from vacation. And decided to pour the whole floor at once, instead of in two pieces. So got to rent the PEX stapler again and put down more PEX. Here is the floor ready for "mud":


Telebelt'ed the concrete in:


Placing concrete:

[kb0thn]

The concrete contractor did not finish the floor to the pit rim as it should have been. Very unhappy about that. Pit rim was dead level. But the concrete is 3/8" above the rim in some places and 1/8" below in other. Pretty pissed off about it. All it would have taken is to run the screed to the rim. But they didn't. And I get to look at it for the rest of my life. I hate concrete guys. But even seeing the defects, he declares the concrete is "perfect". But whatever, it's literally set in concrete. Nothing I can reasonably do about it at this point.


I used the last of the really warm weather to paint it. I hate painting. Prep work takes forever.


Rolled on Rust-Oleum oil based safety yellow. Did a couple of coats and then weather got cold. Will see how it looks next summer. I should have made the rim out of stainless.

[N2 Welding]

Looks like a lot of work. How long did that project take from start to finish? Starting with the backhoe digging to the final painting.

[kb0thn]

Looks like a lot of work. How long did that project take start to finish?

It was a lot of work. Not really done with it yet. Still need to make covers and get the utilities in there and figure out lights.

Looks like the start of excavation was September 13th. Looks like the paint photo was from November 10th. I'd guess 100 to 200 hours in there. And I bet it will be $15k by the time I finish with removeable covers for it. On the Practical Machinist thread someone asked about cost and I broke it down in there.

[N2 Welding]

I know you are going to enjoy having that shop once completed. Thumbs up

[12345678910]

Re the bad rim job.

You could fill the low spots and have a concrete polisher grind it all down to the same level.

[Tarmstrong]

So, I got a question...how are planning to vent that area? Pits will trap dangerous gases if left with circulation...

And I love the build, well documented and well thought out approach. I love these kinds of shop builds.