I am putting a cast iron tub in; can’t decide what to use for shims. Found several ideas in a search, but squooshed copper pipe, I don’t have access to, and lead doesn’t sound good. Since I don’t want to do major excavation work to dig up and replace the drain pipe that may even be sunk into the side of the hole in the concrete slab, I have to have maybe almost an inch worth of shims. None of the people at the stores seem to have solid ideas, either. I don’t want to find out two years from now that, for instance, the hardwood-under-metal is rotten, or whatever other idea was a bad one.

I guess I could hammer down some copper pipe, but an inch’s worth? Doesn’t seem like that would be too stable.

Have you checked the bin at the local hardware store or big box store that has the angle iron? They usually have a large selection of box tubing, strips of metal and sheet metal. If you can find something wide enough to make it stable, you might epoxy strips together to make it thick enough. The other possibility is to figure out how high you need it and then have a machine shop weld up some stock that thick into say a “U” to support the ends and sides?

If you need an inch worth of shimming how out a couple of pieces of concrete stepping stones that you can find at the box stores, probably let you buy a broken one for next to nothing

It will cost some money, but, I would suggest you get some stainless steel and have it cut to make the necessary shims.

I agree with the metal of choice to be stainless. Any other metals and you’ll get a bimetal reaction which will cause corrosion. Another idea might be to put a re-enforced mortar base to raise the base of the tub area to match the drain. You could even use concrete backer board that you would use for tile to raise the area and even tile the area.

IF it were me, star drill (or hammer drill) and masonry chisel would get the rust knocked off because I’d be cutting that drain so everything matches correctly.

I started digging down to try to remove the drain pipe, but there is also crumpled metal at least partially surrounding the drain pipe, down under the level of the dirt. What the heck could that be? I’m so afraid I would *really* be getting myself into unknown territory if I start tearing into that.

Concrete foundations suck. Is there any fitting exposed above ground level? There should be a J trap buried there too. You also need to determine the pipe type so you know if its threaded fittings or sweated iron fittings. You might be able to simply use a large pipe wrench and un-thread the the drain section and have a new nipple threaded that is the right length and fit it back in. They make boots that fit over cut drain sections to join pipe sections, so you can adapt pipe types without threading. but on really short lengths around a J-trap it might not work. It might be a good idea to get an experienced plumber to do this section of the job so you don’t get in too far over your head. Watch them so you learn something about it. Digging around concrete like that is really difficult. Plumbers do it all the time. You might see when they do it that you didn’t want to try that anyway. It might be money well spent.

I’ve never done this but could you make a mold out of wood and melt the copper tubing into a shim the size shims you need I just don’t know how much heat it would take to melt the cooper its a soft metal so i would’nt think it would take alot.