Tricks for breaking out mortared-in clay tiles?

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Dec 30, 2022
Finally getting around to installing my rigid liner and class A chimney extension and the first task is proving much more difficult than I anticipated. The masonry chimney is only about 6ft to the thimble and 8ft to the inside of the fireplace (the wood stove sits on the hearth in front of the fireplace). Because it is so short a distance and the roof is not steep, I figured I could get away with not buying or renting one of those tile breaker things. But I only made it around 2ft down today before I gave up for the evening... turns out the tiles are completely mortared in place. There are 2 clay flues with about a 1.5inch gap between them that is filled with solid mortar and then about an inch of mortar around the other sides. The mortar is kind of weak and sandy so I've been able to make some progress with a pry bar and a sledge hammer, but I'm about at my limit of how far I can reach with those tools. The two flues are also breaking very differently too, the one that I really need out, breaks in big, solid pieces that are then really hard to wiggle apart because they are fit together so tightly (so I'm not sure one of those tile breaker things would even be effective on that one). The other one that doesn't matter as much, flakes apart in layers, but again, I don't really need that one out.

Are there any tricks or tools that would helpful to get the rest of that solid, mortared in, clay tile out?
Tile breakers will smash the tiles into small pieces that are collected on the bottom.

Mortared in tiles just suck. If not too bad, tile breakers may do it. But many times they won't. That's when the grinders attached to rods and air chisels on rods come out
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What is the ID of the clay tile liner? Would an oval liner work or is this an 8x8 tile?
What is the ID of the clay tile liner? Would an oval liner work or is this an 8x8 tile?
They are 8x8 (maybe actually less than that?)... my 6" rigid liner with insulation won't fit down them. I figured I'd have have plenty of space with the clay liner broken out, but based on what I've been able to break out at the top, I'll only just be able to fit the new assembly down the hole (that's with the clay liner and 1in of surrounding mortar removed). The chimney itself is very wide and thick... but it appears to be built solid rather than with a hollow cavity.

I did purchase some masonry blades for our angle grinder today, as well as a heavy chisel (I think it was called a concrete chisel) that I can try to secure to the end of a heavy, steel pole we happen to have here. Thank goodness we are only dealing with 6ish feet of chimney!

I'll check in again once I take another stab at it. Thanks for the help!
Tricks for breaking out mortared-in clay tiles?Tricks for breaking out mortared-in clay tiles?
This is the chimney, for reference... I remembered I had taken photos last winter when I first started on this project.

For a follow up question, I am planning to pour a proper crown to reduce water damage to the brick/mortar... is there a general rule for how thick it should be? I'll need to plan ahead for it so the liner ends up being at the appropriate height to connect to the transition plate, which will be secured to the new crown. *if it matters, I'm in PA and we get some pretty cold, wet winters... in case that makes a difference.