DIY Aluminum Drain Tables

I have a 8x12 flowering area and have wanted to install drain pans for a while now. I currently have plants on caddies which is nice but I'm not fond of squatting to feed them. I decided to DIY after seeing that it would be the best way to get exactly what I wanted. Each pan draining into the next, space for two rows of plants wrapping around 3 sides of the room and a single drain outlet. I played around with using lumber for the frame and while not ideal I had came up with solutions for it's shortcomings. But I decided to go all out and build the whole thing out of aluminum. It ended up costing a good bit more but I think I will be pretty happy with them and they'll last a long time.

I'm pretty happy with the design choices with a couple exceptions. 1- the table top is screwed down with 316 stainless self tapping screws. Foolishly I didn't realize until I put two of the tables together that those screws will be running across the pans in two places and will get wet on the regular. Stainless and aluminum are corrosion resistant on their own but they tend to do poorly when paired and wet. The aluminum will start to corrode first where it contacts the screw heads. How long that will take I don't know. My choices are; see how it goes, work in some silicon to seal the aluminum/steel contact around the screw heads, or replace the steel screws with aluminum bolts. Haven't decided yet but the smart thing to do would be to replace the steel with aluminum. 2- I wanted the drain pans to be sturdy so I went with .065" sheet. I could have gone thinner. I was unable to cut into the sheet with hand shears. Fortunately I have a nibbler and was able to nibble out the corners. I wanted the sides to be 2" high so I ordered a set of 2" hand seamers (the standard is 1.25"). It was a chore to make any progress with the bends but I finished the first pan and started on the second... and then the expensive set of seamers I just bought snapped in two. The second pan was beat into shape with a rubber mallet. I have one more pan to go. Once the third table is complete I'll put a bulkhead on the end connected to a rubber hose.

Will be glad to answer any question about tools, materials, etc. Will update the pic once they are finished and installed.

Might as well add the build specs. I did run load calculations and research the alloys so if anyone does something similar it should be pretty stout and able to handle all the plants you can put on it. I use 2.6 gallon pots so the table rails might need to be upgraded if using larger pots.

All aluminum tubing, angle, and bars are 6063 aluminum alloy.
legs: 1.5" (width) x 1/8" (wall thickness) square tubing
Side rails: 1.5" x 1/8" angle
Support struts: 3/4" x 1/8" bar
Table rails: 1/2" x 1/16" square tubing

All hardware is 316 stainless
The side rails are attached to the legs with: 2" x 1/4" bolts
The struts are attached with: 2" x #10 bolts
The table top tubes are secured with: #10 self tapping screws (may want to modify this, at least where they cross the pans)

Self tapping screws require pilot holes. Use some oil when threading them in. While the holes on the frame for the support struts were hand drilled all the other holes for bolts and screws were done with a drill press. A hole punch and hand drill could be used if you don't have a drill press. Using the hole punch is a good idea even with the drill press, though I skipped it on some things (aluminum bar bolt holes and aluminum tubing on the top). Steel washers on both sides of the bolts help protect the aluminum when the nut is tightened and provide a little more surface area for better clamping.

Pans are made with .065" 5052 aluminum sheet. 5052 It's a little more malleable than 6063 and has slightly better corrosion resistance. They are also secured with 2" x 1/4" steel bolts. I'm using rubber washers between the side walls and the steel washers to prevent steel/aluminum contact. As mentioned water+steel+aluminum will corrode.

I used a 1/4" per foot grade for drainage.

The legs are 25" high, almost 26" with the side rails and 1/2" tube sitting on top. This is going to be a good height for me at 5'11" tall, top of pots will sit right at 35". The pans are 28" wide with a 31" frame width. Top rails have 3" spacing.

If I had taken it a bit slower I could have completed the pans without snapping the seamer, but I would highly suggest using a thinner gauge sheet. It's also possible wherever you source the metal will do the bends for you.

Any questions, feel free to ask.

I has the sheets pre-cut but I cut the rest myself: chop saw is a very useful tool for cutting metal up.

Another useful tool: deburring tool. Run this around all the drilled holes exit points for a nice smooth finish. The alternative is sanding which isn't going to look pretty, or just trying to pry the burr off which isn't great either.

Boy, that cost ya a little coin I'm guessing? looks cool man, nice job.

Thanks and yes, about 1000. I might have saved about 100 using a thinner sheet metal. The hardware alone was about 150. It's crazy how much a few bags of nuts and bolts cost.