Use a 1/2 " white marble slab for a bathroom counter top?

I have this here white marble slab.
My head's sink countertop is 3/4 plywood with formica sheet on top and an aluminum trim band.

I have been wanting to redo the top.
Do you think marble would be a good idea on a boat or would it crack?

I can cut it myself and even get a diamond jig saw blade for the opening.
The size is about 22 by 26. Sink is like 18"width by 12" depth.
So that leaves a couple inches on either side of the marble at it's farthest width. The marble will sit on mahogany plywood base cabinet.

Would a ceramic cast iron sink sitting on 1/2 inch marble sitting on a mahogany plywood base cause the marble to crack? Say as the boat moves.

Is it worth the effort to do this?

The marble is a smooth polished flat surface of mostly white color.

The piece I have is about 3 by 3 foot and surprisingly heavy.

I would be more concerned with the weight and its effect on the boat than anything else. You might find that a marble countertop and a cast iron sink would cause the boat to list to one side.

I think you can do better.

WesK said:

I would be more concerned with the weight and its effect on the boat than anything else. You might find that a marble countertop and a cast iron sink would cause the boat to list to one side.

I think you can do better.

Click to expand...

I can of course, but the marble is free.
It may also be thicker, I need to recheck.

The sink hole cut out does drop some weight.
I ought to weigh this slab and see how much weight it actually has. Then get a rough idea of what the finished piece will weigh.

The sink is OEM.

I have a piece of Corian, but not big enough. They want a lot for scrap pieces.

I don't think this piece would weigh enough to change the boat's center. I am more concerned It would snap. My Father in law, got this old church marble altar, and it has lots of pieces, and we need to do something with it. I think this slab was part of the side. It is a part of his estate.

SD, that setup will be fine. Be sure the 3/4" plywood is well supported all around; it must not deflect. Bed the marble well in cementitious tile cement (not the crapola water-soluble slimey organic thinset adhesive that diy'ers used to use). Bed the sink on sealant with perhaps 1/8" depth betw sink and marble. Do not use 5200 for the sealant! Should you ever need to remove the sink, either the sink or the marble will be in shards! (I mounted a vitreous china sink under an epoxy-coated 2" thick oak countertop (in my basement); when the sink broke(!), it was an awful job to remove w/o damaging the oak. Pic shows the sink that I broke by over-tightening the drain fitting, the replacement looks the same.)

My taste is always for an 'undermount' sink, with the marble top fitted flush with the bowl. (Normal practice is for the top to overhang the bowl to hide a poor fit and the sealant line.)

Normal marble or granite tops are 1- or 1 1/4" thick and they're normally self supporting (no plywood).

Fancy boat builders often use honeycomb core stone panels for this service. Lighter, stiff; pic below. (Fiberglass inside surface - aluminum honeycomb core - fiberglass layer - stone surface.) (All the stone panels on the interior walls, and the rooftop penthouses, of the National Constitution Center are this stuff.)

Wes is right to note the weight. But 22x26" is not that big and perhaps you could be satisfied with a ceramic/vitreous china sink (same colors and wearing surface but would be lighter than cast iron). You may well see or expect a list but a case of beer on the other side of the boat would cure it.

The marble is thicker, was in the garage and glanced at it, it is either 3/4 or 7/8 thick.

My idea is get rid of the plywood shelf, and just place the marble on top the cabinet.
The cabinet edges have long pieces of mahogany that reinforce the edge of the mahogany plywood. The existing top is screwed down into those wood strips.
Both sides of the cabinet are well supported. One side is screwed to a 3/4 plywood bulkhead, and other side screwed to another mahogany plywood cabinet

This is fairly small surface. It is fully supported at least front and sides.
It will be one of those winter type projects.

I will remove the existing plywood top, and use it as a pattern. It is one of those one shot deals, if I mess up the stone, but an interesting project.

I weigh 200 pounds and my walking around in the boat I don't notice creating a list. The head is about midships of a 37 foot boat.

This current cast iron porcelain sink is not glued down. It weighs so much it just sits on there fine. I suppose being so heavy is a positive thing. I don't want to glue it to the marble. The marble will have to be glued to the cabinet. My plan is to use PL premium construction adhesive, which is my all purpose go to glue..

I can cut the marble on my table saw using a diamond blade. The edges I think I can smooth using a grinder blade or maybe could be belt sanded, will experiment with the stone first.

Marble is OK but it does pick up stains more than granite or many other materials especially white marble.

SD,

The 3/4" slab will probably make the span.

Consider water-cooled diamond tile/stone cutting tools. A $1 boat dollar cheepie can be had from Lowes. Also consider water-cooled grinding and polishing tools. Basically cheap electric angle grinders equipped with a water supply. You can buy many grades of diamond discs with hook-eye backs to fit these grinders. You can buy triangular diamond pads with hook-eye backs that work with your Fein or similar multi-tool (better ones from online suppliers but The Despot has some, too). Handy, but not necessary for your project, is a water-cooled Partner or similar masonry saw with diamond blades. You can certainly cut tile, brick, and stone with dry masonry-cutting wheels in dry tools but the dust is VERY tough on motor bearings and lungs. There are dry diamond wheels suitable for an angle grinder. Gotta' be very careful with temperature cracking the work.

Pics: cutting granite with the Lowes cheepie tile saw, polishing an antique marble tread; cutting the tread to make door sills (that's a jon boat trailer fitted to suit a Flying Dutchman and with a plywood deck), an antique marble doorstop and a copy I made with the above tools, antique brick pavers ground clean.

The marble will be fine.

I have had a green marble bathroom countertop for two decades and it still looks new.

I also have a green marble coffee table and I think the tpo is about the same thickness as your piece. Had the table for a couple decades as well, and it's held up fine.

You can cut your marble on any good wet saw. Marble is pretty soft.

sdowney717 said:

I have this here white marble slab.
My head's sink countertop is 3/4 plywood with formica sheet on top and an aluminum trim band.

I have been wanting to redo the top.
Do you think marble would be a good idea on a boat or would it crack?

I can cut it myself and even get a diamond jig saw blade for the opening.
The size is about 22 by 26. Sink is like 18"width by 12" depth.
So that leaves a couple inches on either side of the marble at it's farthest width. The marble will sit on mahogany plywood base cabinet.

Would a ceramic cast iron sink sitting on 1/2 inch marble sitting on a mahogany plywood base cause the marble to crack? Say as the boat moves.

Is it worth the effort to do this?

The marble is a smooth polished flat surface of mostly white color.

The piece I have is about 3 by 3 foot and surprisingly heavy.

Click to expand...

I have marble countertops in both heads, each is about 1/2 of the size of the piece you are considering. Marble is soft enough to cut or drill easily. I change out the tap sets in both heads, from the cheapo sets that came with the boat, to a nicer looking arrangement. This required me to drill a third hole, for the different style, and the drilling was relatively easy with a diamond hole saw. After 37 years the countertops themselves look like new.

I have also changed out my galley countertops for Quartz tops. These weigh in at between 150 and 200 lbs, were quite awkward to get into the galley, so will never leave. I had the supplier cut the holes for the sinks, stove top and corner cupboard access, and polish those edges. I replaced the fiddles to cover the un-polished edges. The weight didn't affect the trim noticeably.

Changing up to a 12 ft Caribe with a 40 on the davits did far more to the trim, so now I have to put the beer on the Stb side instead of on Port.

Picture of the marble I would use, it is 1 inch thick.

Pics of the old church altar. Large solid chunks, it is in good condition, not perfect. These would make nice bench seats?

Can I sell these to someone, and what would be a good price?
One is upside down and on other side has small carved crosses.
Craigslist them?





Some smaller pieces

Yup, Craigslist can sometimes be a fine source.

Fun to be had: I bought an antique, 19th c. marble fake fireplace surround, made for a heating duct grille) listed on Craigslist. I intend to install it as a fireplace surround (and not use the middle piece that had the heating grill).

(Pics include: 1, a fireplace at Awbury Arboretum of the sort that were once available to burn gas, or coal, or charcoal; friends have a similar one with a plaster inner surround that burns wood. 2, my purchase laid out on the floor as it once appeared with the grille. 3, the pieces laid out w/o the grille. 4, the Colonial Revival surround from over a century ago.

DHeckrotte said:

Yup, Craigslist can sometimes be a fine source.

Fun to be had: I bought an antique, 19th c. marble fake fireplace surround, made for a heating duct grille) listed on Craigslist. I intend to install it as a fireplace surround (and not use the middle piece that had the heating grill).

(Pics include: 1, a fireplace at Awbury Arboretum of the sort that were once available to burn gas, or coal, or charcoal; friends have a similar one with a plaster inner surround that burns wood. 2, my purchase laid out on the floor as it once appeared with the grille. 3, the pieces laid out w/o the grille. 4, the Colonial Revival surround from over a century ago.

Click to expand...

Looks very nice. You seem to know marble a little, what should I try to sell my pieces for? I would like to sell them together. Maybe throw in the smaller pieces for freebies.

Very little that I'm smart enough to not do.

Re: pricing stuff, look for comparables on your chosen venue. Check out architectural antiques places; many have an online operation. I 'shopped' for quite a while before I found the fireplace surround and it was both local and well underpriced.

could you get them to grind out 3 or 4" squares leaving ribs for strength? One of the boats here refit with marble and had that done. They said it led to considerable weight savings.

After installing marble counter tops in the galley this boat had to address other issues.