Perhaps wrongly, but I was told commercial drain cleaner stuff solidifies the stuff that's clogging the drain into a concrete type of substance.Oddly enough, commercial drain cleaner is sodium hydroxide, (lye) the same stuff needed to make the soap, but you guy's knew this.
It can wreck plastic because people tend to use too much and don't follow the instructions, sodium hydroxide and water produces a lot of heat quickly because of an Exothermic reaction.
Stick to the instructions and you should be fine.
Shouldn't do, if it's mostly fat and oil blocking the drain. Soap has to have free fat, more fat than needed to make the soap. For two reasons, one to stop there being any unspent lye remaining in the soap, and the other as a skin conditioner. The drain cleaner, if it is sodium hydroxide, should heat the fat and oils and turn them into soap, which then should dissolve.Perhaps wrongly, but I was told commercial drain cleaner stuff solidifies the stuff that's clogging the drain into a concrete type of substance.

Never a blocked sink that the cheapo plastic snake didn't suffice. You understand the chemistry ,obviously, more that I.After watching this video, it looks like it depends on how much fat has gathered. These people had to use a drill and chain to break the fat out.
Edit: I think it might be to do with packing. The hydroxide may only affect the top layer of fat blocked in the pipe, while the fat underneath remains untouched. So maybe drain cleaner is more of a maintenance thing rather than an unblocker. I have to say, I've yet to have a blocked sink.
Access is the only real issue. New bends and traps come with the new seals usually.I don't know if the plumber was simply justifying his charges but he was an age in applying new O rings, silicon to the threads and liberal amounts of ptfe tape in other areas, it might be something to consider if you go down the route of replacing the U bend yourself. There is also the fact that U bends are always in the most difficult of places, half the time the plumber was on his back looking at the underside of my sink.
Half way through I am pretty sure that I would utter my well used phrase, sod this for a game of soldiers. I cannot say that I have much patience for diy plumbing, my last attempt produced more leaks than the combined efforts of Wales and MI6.
Wait a minute !!!! PTFE tape ? Was that on a plastic joint ? I work in a FE college attached to plumbing and electrical, never seen PTFE used on plastic joints as well as silicon ?I don't know if the plumber was simply justifying his charges but he was an age in applying new O rings, silicon to the threads and liberal amounts of ptfe tape in other areas, it might be something to consider if you go down the route of replacing the U bend yourself. There is also the fact that U bends are always in the most difficult of places, half the time the plumber was on his back looking at the underside of my sink.
Half way through I am pretty sure that I would utter my well used phrase, sod this for a game of soldiers. I cannot say that I have much patience for diy plumbing, my last attempt produced more leaks than the combined efforts of Wales and MI6.
Plastic compression joints are a pain at times too. Easy to cross thread or break by over tightening. I used to do kitchen, bathroom and toilet remodels for a living and had a few plastic fittings not willing to play nicely. Even with the supplied seals, LS-X or ptfe had to be used.Access is the only real issue. New bends and traps come with the new seals usually.
I think the plastic snake works on the same principal as the drill attachment with the chain wrapped around it, as in the video. If I get a blocked sink, I will look for one of these snakes.Never a blocked sink that the cheapo plastic snake didn't suffice. You understand the chemistry ,obviously, more that I.

I would only use them together if I still had a leak after using LS-X on the seal. I would use PTFE on the male thread of the fitting, so I could get a tighter clamp down on the seal without it slipping on the thread.Wait a minute !!!! PTFE tape ? Was that on a plastic joint ? I work in a FE college attached to plumbing and electrical, never seen PTFE used on plastic joints as well as silicon ?
This. My bothersome sink has a pedestal and I can’t get the bugger out.Access is the only real issue. New bends and traps come with the new seals usually.