Any advice for destroying a piano?

Definitely remove/de-tension the strings.  Some cheaper pianos are hot-strung.  That basically means that one part of the factory makes the harp and puts strings on it, the other part of the factory makes the cabinet, then they put them together and do final tuning.  The harps are self-supporting of the string tension.  Good pianos are post-strung and have a harp that gets part of it's rigidity from being attached to the wood, so the strings can't be tensioned until it's installed.

Hot-strung means crappy sound because the wood it's attached to isn't actively carrying the vibes/resonance into the wood as well, but it also means you can basically destroy the cabinet and worry about the harp later.  If you do that with a post-strung piano, you risk the harp imploding with 20 tons of force when you take away the support it needs from the wood around it.

Take the strings off first :)  You can do it with side cutters and eye protection, but after you cut 100 strings you'll have a blister and three cramps only to realize you still have 400 left to cut.  With proper protection (face shield, gloves, all skin covered with denim or leather) you can make quick work of them with a cut-off wheel in a grinder.

The strings themselves are usually made from high carbon steel and the larger/lower strings are wrapped with an alloy of carbon steel and a little copper.  Not much money in the recycling game for them, but worth saving as they could be 50 lbs.

Curtis73 (Forum Supporter) said:

Definitely remove/de-tension the strings.  Some cheaper pianos are hot-strung.  That basically means that one part of the factory makes the harp and puts strings on it, the other part of the factory makes the cabinet, then they put them together and do final tuning.  The harps are self-supporting of the string tension.  Good pianos are post-strung and have a harp that gets part of it's rigidity from being attached to the wood, so the strings can't be tensioned until it's installed.

Hot-strung means crappy sound because the wood it's attached to isn't actively carrying the vibes/resonance into the wood as well, but it also means you can basically destroy the cabinet and worry about the harp later.  If you do that with a post-strung piano, you risk the harp imploding with 20 tons of force when you take away the support it needs from the wood around it.

This would be amazing while ablaze, though...

Fine fine, I'm trying to figure out a way to get it outside, by myself, to do some of these fun idea with. 

Sliding door is out, because it's brand new and not risking it.  That leaves going down the hall and through the garage.

First problem is a 4 inch step up to get into the hall, next another 4 inch step down to get it in the garage, then the cracked garage floor and serious dip at the door drain area with metal grating in it. 

I don't have a jack low enough to get under the piano. I might have some 4x4 scraps I could try to cut at an angle to act as a ramp. Steel digging bar could be used as a lever, but, could also damage the finished stone floor in the room the piano is in. 

Wait. There's a standard entry door in the basement at the sidewalk. Piano would wind up in the grass, but I need to check the floor there, that might get it outside. Probably wind up in the yard because there's not enough room or door width to swing the piano around to stay on the sidewalk, but, outside. 

So there's a two inch step to the threshold, then a 3 inch drop outside. And enough sidewalk space I could probably turn it around. 

Oh good, the wheels don't spin.

I once dumped one out of a dump truck down into a landfill pit and watched while they ran the compactor over it.  That was fun and satisfying in a clangy smelly sort of way.

In reply to Grtechguy :

I admit as a musician I hate to see it, it's kinda like people who cut up miatas for scrap because they don't see the value in them.

But, at a certain point a lot of pianos are worthless too

I got a couple cheap harbor freight furniture dollys to move ours. Worked good enough 

In reply to BlindPirate :

They are surprisingly strong. I have a 16" lathe sitting on 6 of them. Right at 3000 pounds. It doesn't roll easy but it does roll. 

If you use a propane torch on the piano wires, they'll de-tension nicely and then you can cut them much more safely using either a pair of side-cutters or a grinder with a cutoff wheel. A sledge works well for dis-assembly, and for turning the cast iron harp into manageable chunks.

I forgot,  I wore a face shield while I cut the strings with a grinder. Can't say I would recommend it though. It did make cool sounds.

I had to cut the strings to get to some fasteners