Removing a top-mount cast-iron sink

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Aaron
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Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 2:48 pm

So I have a chipped, scuffed, stained, and otherwise crappy white porcelain-enameled cast iron twin-basin kitchen sink. (There's a mouthful.) I got a free high-end stainless steel sink in like-new condition from a buddy who is renovating his kitchen. It's made by Franke and has really nice straight sides and 90 degree inside corners. The bonus is he gave me the old Moen faucet with it, which is super nice as well, with a pull-out sprayer and stuff. It's perfect because my current faucet is leaky and beat up too, and I've been putting off laying on my back under the sink and fussing with awkward faucet wrenches to remove it.

Anyway, the hard part is just removing the old casty. She's glued into a rough opening in laminate countertops with silicone around the perimeter, and her sheer weight with the silicone underneath prevents movement.

I've already used a razor and scraped away as much silicone as possible from the sides of the rim, but there is going to be silicone sandwiched between the counter and the rim that I will just not get to that easily, especially on the back of the sink where the backsplash leaves no real room to maneuver a knife or razor under the rim.

Anyone have a particular magic method for this scenario? The best thing I can creatively imagine is using two bottle jacks under the sink, one under each basin, with a piece of wood propped between them and the sink. I could apply gentle lifting pressure if I can nudge the sink up just enough to slip a razor under the rim and cut away more silicone.

Or maybe a hand-sledge hammer to bust it up? Cast iron sinks shatter, right, with dead blows?

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Re: Removing a top-mount cast-iron sink

Post by Shannon » Fri Sep 20, 2019 3:21 pm

I think your idea of the upward pressure would sure help. Not sure on the construction of your cabinet bottom but I would be inclined to put down a larger piece of plywood under jacks to spread out the pressure a bit just in case? The jacks along with a razor knife or even red bar should get it free , just be careful not to damage the laminate in the process.

Breaking it apart will likely not help much if it’s still stuck down around the perimeter.
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 4:52 pm

Yeah that is a good idea. The floor of the cabinets are just that typical particle board that factory cabinets are made from. I do happen to have a scrap piece of plywood. I may even have a scrap 2x8 or x10 or something to put under the jacks in addition to the plywood to create even more equal distribution of downward pressure.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Fri Sep 20, 2019 7:07 pm

Good call on adding support under the jacks to keep from falling through the bottom of the cabinet.

I too would use a jack, or two, under the sink to apply a little upward pressure. I think I'd recommend starting with one on one end of the sink, apply just a little pressure, maybe 100 pounds or so, then start working your razor under the lip of the sink until you get it to start breaking free on its own. Maybe add a little more pressure as you work.

Lifting one end will focus the lift pressure on a small portion of the joint you're trying to cut free, thus increasing your chances of success without collateral damage. Hopefully the installer was reasonably frugal with the silicon so that you don't have "snot welds" under the sink to further hamper your efforts.

Being able to do the faucet with the sink out is infinitely easier than messing around under the sink upside down on your back with crizzap falling in your eyes. Which reminds me, safety glasses would be an excellent choice here.
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 7:41 pm

The installers were my Dad and me, about 15 years ago. Lol

I have some vague recollection of my dad being a bit generous with the silicone, with the spout of the tube cut so it had a 1/2" diameter opening. I hope that my memory is wrong. :? :|

So I may be a bit screwed. Pushing up on the sink may tear the countertop up from the mounting boards if acted upon too aggressively.

Good idea pushing up on one side, that could be better physics. Actually I may just get by with the one bottle jack that I have, may not need one for the other side.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Fri Sep 20, 2019 7:55 pm

Unfortunately, if he was too generous with the silicon, you have more than just the lip welded to the counter, and it will be a fun time trying to get around from underneath to cut from below. If you lift too much, you run the risk of ripping the laminate off the countertop or the countertop from the cabinets, so be very cautious with the amount of pressure you apply with your jack as you get started. Once you've got it starting to come loose, then you can "chase" the bead around the rim of the sink with the jack and the knife.

Maybe it's time for a new countertop as well? :lol:
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 9:41 pm

Oh scheisse. It's what I feared:

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We must have used a whole damn tube of silicone. :(

This may be a fruitless project, I may have to abort it.

I wouldn't mind new counters, these laminate ones are pretty crappy. But it's sort of a crappy house so if I did replace the counters I'd probably just get new laminate ones.

Hope to move out of here in the near future.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Fri Sep 20, 2019 10:01 pm

Before you get too carried away with pulling the old sink, are you sure that the new one is going to use the same or larger footprint?
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 10:38 pm

Yep, both sinks are the same dimensions rim edge to rim edge, length and width, 33" × 22".

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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 10:51 pm

Another strategy could be an oscillating saw, with a flush-cut blade. I could shield the counter with a thin piece of sheet metal perhaps.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Fri Sep 20, 2019 10:54 pm

I think I'd stick to hand tools, an oscillator will be too easy to scar the counter with.
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Fri Sep 20, 2019 11:17 pm

Yeah I kind of agree, too risky. I'm on the fence about this whole thing. The big blobs of silicone under the sink are really a dire warning to me of a potential clusterfuk.

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Re: Removing a top-mount cast-iron sink

Post by Shannon » Sat Sep 21, 2019 7:10 am

What about refinishing the sink in place, unless you are willing to take the chance of replacing the entire top?
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Sat Sep 21, 2019 12:02 pm

Yeah I thought of that too. Unfortunately I just hate the damn thing. When metal pans scrape the paint finish it leaves black marks. It's just a pain in the butt to keep clean. I then foolishly used a bunch of abrasive cleansers on it which only made it worse and more prone to stains.

My dad wondered at the time we put it in why I didn't go stainless in the first place. He was right.

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Re: Removing a top-mount cast-iron sink

Post by Aaron » Mon Sep 23, 2019 12:00 am

I got another tip from my fried Ryan to try. He said use a long but very thin length of wire and use it to slide under the ridge of the sink, stretch it taught and use it in a sawing motion to cut through the silicone.

That's pretty darn clever. Maybe even dental floss itself might actually work?

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Re: Removing a top-mount cast-iron sink

Post by Shannon » Mon Sep 23, 2019 7:00 am

may work? Let us know
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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Mon Sep 23, 2019 9:26 am

I thought of the wire thing as well, but silicon is really grippy, so I doubt you'll be able to pull the wire through it, or keep it taut enough to get it to work anywhere but at the corners
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Mon Sep 23, 2019 1:21 pm

Yeah, the silicone just laughed and broke the dental floss. I think if wire were both thin and serrated, somehow, to grind away the silicone...

Another technique I was researching is using a propane torch on a 1" putty knife to heat it up and hammer it in to a side. Then pull it out and repeat a couple times. After it can get deep enough, tap a shim in it. Repeat around the sink so it's lifted enough to really cut the silicone. Bottle jack may not be needed. Or could augment the process if used very carefully.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Mon Sep 23, 2019 1:53 pm

The only wire that might be strong enough and/or serrated will be a piano or guitar string. I still don't think it will work.

Wedges will definitely be helpful because, like the jack, it will put tension on the joint to keep it open as you cut enough of the silicon to start getting the sink to release. This tension will work in your favor, helping to "tear" the joint as you cut the silicon.
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Mon Sep 23, 2019 7:23 pm

Yeah I have my doubts piano/guitar wire would work, too, because there's probably no such wire thin enough to slip under the rim with weight of the sink. I can't get the Olfa razor knife blade in further than like 1/6" from the edge of rim.

For shims I think those nylon ones that are for toilets might be good.

If I can just get it pried up JUST enough to keep working at it, it may work... starting at the corners would be key, I think.

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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Mon Sep 23, 2019 9:54 pm

Yep, start at the corners
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Re: Removing a top-mount cast-iron sink

Post by Aaron » Tue Sep 24, 2019 1:57 am

Yay! So with a hammer I tapped some nylon wedge-shims into the corner (they're really for leveling toilets) and they slipped right in. Pop, pop, pop! The sounds of the sink silicone separating from the counter.

This is gonna work! No bottle jacks needed! Just need to use the Olfa knife, cut as far as I can go, then tap in another shim to lift up more sink!


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Re: Removing a top-mount cast-iron sink

Post by A. Spruce » Tue Sep 24, 2019 9:04 am

congrats!
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Re: Removing a top-mount cast-iron sink

Post by Shannon » Tue Sep 24, 2019 5:15 pm

Glad that worked out well.
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