It was taking around 24 hours to drain just ~1—3 liters of water in my kitchen sink. Probably comparable to IV drip speeds. After a huge effort and expense, I finally fixed it without demolishing the kitchen – which would have been my next and final move¹. Sequence of events:

• tried many boiling pots of water to melt any grease

• tried 3 varieties of cheap drain cleaners, the contents of which are not always known due to trade-secret protectionism (when most likely it’s just bleach or lye). Also poured down ordinary household bleach (likely in the typical 15% concentration).

• removed trap and all joints… down to just the wall opening.

• snaked the line with a simple snake. Took all day to get the snake inserted because apparently there are many hard 90° turns. It kept hitting a wall & required lots of force and spinning. Poured boiling water in with the snake inserted and it drained quickly. Pulled the snake out and it was slow again. Repeated the process several times and one late night just left the snake inserted figuring i would deal with it in the morning. Pulled the snake out and it was permanently curled up like a pig’s tail. I guess it hit such a hard turn that it coiled up inside rather than progressing down the line.

• cut off the meter or so of curled up snake. Used a blow torch to soften the new end and pulled on it with pliers so the end was a little stretched as they come from the factory. Bent some copper pipe, drilled a hole in it, threaded it, added a screw, so I could use the pipe to force the snake to spin close to the drain entry point. Made no difference. Bizarre twist: a small amount of hair was on the end of the snake, yet this is a kitchen drain. This suggests the snake went deep enough to reach intersecting drain pipes. But if that’s true, then why was it coiled up? That remains an unsolved mystery. After the last use a new kink occurred higher up so the snake is ruined.

• every week poured a different brand of enzyme based drain cleaner following warm water to warm up the pipes & let it sit for 6+ hours. Used 3 different enzyme brands on weekly rotation.

• tried a two component drain cleaner: ① sodium hydroxide + ② sodium hyphchorite with sodium hydroxide (yeah, sounds redudant but bleach is really in both components)

• custom built a leaf blower connection using a series of PVC pipes, some softened with a heat gun to tightly fit to the blower. Not kidding. Gave it full force and got no results. Thought at the time that this was the nuclear option.

• bought an “auger”, which is a snake inside a box with a crank & essentially the same features I added to the simple snake. It also hit a wall & could not make one of the turns. It came out clean, but with a kink from pushing on it (which is what you do when nothing else works).

• asked IRC chem channel for advice. My questions were chem related but they really do not want to hear too much home improvement chatter. Can’t say I blame them but the best chem knowledge would come from chemists not home DiYers. Someone said get sulfuric acid “if you can”.

• (illegal) found a source for sulfuric acid, which is illegal for consumers in my region. Poured only ~30ml down the drain (much less than directed but this stuff is costly), heard it sizzling. Instructions say wait 15 min then pour cold water. I waited 20 min before topping off with cold water. No progress. Took all night to drain as far as i could see. Poured ~300ml more down the drain. Sizzling. Smells like vomit. Bits of white junk show up… probably part of a “#fatberg”. But still no progress. When the visible drain is clear, added ~170ml more (giving a cumulative total of ½ liter at this point, which is actually the directed amount to pour in one shot). Still no progress.

• bought a bicycle pump style plunger. This thing can mate directly with the pipework. Used it just to push water down. It worked to just quickly push the water further down, but then topping up with water showed it’s still clogged. So then I did the pumping action with the plunger. I wanted to resist this because I don’t exactly want sulfuric acid getting sucked into the new plunger and slashing around. Finally the clog is clear. Cleaned the plunger with several full pumps of clean water.

Now it drains 5 liters of water in 29 seconds. Wow what difference. I can even see the tornado in the sink, which I don’t recall if I ever saw that in this sink.

Costs of chemicals and tools were, shit, roughly like:

25- snake (destroyed)

25- auger (cheap compared to most augers, kinked)

20- brand A enzymes

18- brand B enzymes

21- brand C enzymes

5- standard drain cleaner brand X

8- drain cleaner brand Y specialized in hair (because common drain cleaners are useless on hair)

10- drain cleaner brand Z

20- 1 liter sulfuric acid

15- PVC parts for leaf blower

8- simple plunger (useless because it just pushes trap water out the overflow)

10- bicycle pump style plunger (apparently the most critical tool)

So probably roughly ~150 in costs.

IMO the sulfuric acid was essential for loosening whatever I had in there (probably a fatberg), but the final success came from the bicycle pump style plunger directly on the line.

(edit)

Adding footnote 1: well, I did have one really bizarre idea that I was going to try next before demolishing the kitchen. An unused toilet happens to have accumulated a colony of “sewer drain moth fly larvae”. I thought: why not scoop up those worm-like things and drop them in the standing water of the clogged drain? They’re generally considered pests, but if they were to chow down on the clog, they would be helping me out. Luckily it did not come to this. They may have also have risked adding to the clog. In fact, for all I know, they could have been contributing to the clog. I don’t know for certain if it was a fatberg or what down there.

(Apologies to anyone who happened to be chowing down on a burger from #Fatburger while reading this post.)

Options that I nixed:

1. someone suggested bailing wire. It’s stiffer than a coat hanger so I really don’t think it can handle all the sharp twists and turns of my drain pipe.

2. pressure washer hose designed for drain cleaning-- I think it’s also too stiff for the sharp turns of my drain pipes. The plastic hose would get scraped on every turn and thin out the walls of the hose. The tip has an overhang that could get stuck when pulling it out. I think these are just for big outdoor drains/downspouts.

3. huge doses of enzymes, not just the weekly maintenance amounts-- enzymes are /costly/ & my expectation of them working to clear a big amount of junk at once is quite low. I think they are good for just slightly removing thin layers of buildup.

4. gasoline, matches-- became increasingly tempting

Unanticipated damage:

The acid fizzed up and overflowed a bit. It’s like pouring a beer and not well anticipating size of the head. The water top may have been closer that I thought. Some dripped onto galvanized steel radiator pipes that run below the drain and a PEX pipe. The PEX seemed to take it okay but sulfuric acid is said to be extremely corrosive to metal. The pipes were very shiny right where the drops landed and had black rings around those splatter points. Then the shiny part rusted within hours. I think those areas of the pipe are now de-galvanized. I rubbed the affected area with steel wool then painted using a Rustoleum type of paint which is meant to go straight onto rust.