Create large objects from epoxy

Question

I purchased an apartment some time ago, all the repairs are mostly finished. Because of some oversight, I am not in a lose-lose situation. In the bathroom, I do not have enough space for the sink that I want, because of the door placement - please read that the sink is about 5cm bigger than the available space, not allowing the door to open properly.

My alternatives are:

1. break the wall to move the door, re-make repairs to the wall (including wall tiles);
2. replace the door, to open on the other side;
3. buy another sink, live with the regret that I do not have the sink that I want;
4. create a sink "from scratch" with the proper dimensions, with the desired shape.

Now the question is: is the epoxy resin a proper material for that? Are there kinds of epoxy to be avoided?

I saw many videos on the net of people creating tables from epoxy (by poring it in "holes" in wood), or other smaller objects. What I need is a big(ger) object, which should have enough strength by itself, considering the intended use.

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Are there any generic, good quality tutorials about how to use epoxy for my purpose? I am sure that the videos do not give all the "secrets" - e.g. the thickness of the epoxy layer needed for a certain strength.

Note: I am aware that some special shape under the sink will give more strength (by providing support), as well as embedding some metal "wires".

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@Fixer1234 provided a very comprehensive comment, with excellent questions. I will go to answer them, to the best of my abilities.

Not a bunch of great choices.

I know, but that is pretty much it.

Can you add some detail on the sink and the space issue? Is the sink a vessel mounted on top of the counter, molded into a countertop on a vanity, a single-piece stand-alone sink mounted to the wall or on a pedestal (different considerations and potential solutions for each)?

This is (almost) exactly what I want:

Can you add a diagram of the bathroom showing the issue?

The diagram is below. I do not have measurements, and it will be a long time before I can make them. But the situation is properly described.

Are you envisioning casting a huge, solid resin item rather than resin coating a fiberglass form or a concrete casting?

Well, that is a topic I did not have in mind. Even using epoxy as a "raw material" is a new idea.

I have no idea what the "fiberglass form" stuff is, but I might be able to shape a support from polystyrene, and "dress" it with a layer of epoxy. Main question: will it be strong enough? It would be very easy to shape details separately, and then to put them together, adding epoxy to the "corners" to seal it.

Do you need the sink to be transparent?

No. Actually, I want to store stuff under the sink, so transparency should be avoided, I guess.

Are you envisioning just a uniform molded block of resin, or embedding decoration of some kind within it?

As I stated before, I might think about creating some parts, to be joined at the and, instead of creating a crazily shaped mold from the beginning.

Do you have some experience casting big resin items?

The only experience I have with epoxy until now is watching videos :)

What makes the sink you want unique (a particular shape/style/design that might be available in a size that would work vs. a one-of-a-kind work of art)?

Size (being 2-in-1, wide, with large storage space below) and the wavy pattern.

If there's any chance you can buy what you want in a size that will work, that will save you a lot of headaches over any of the alternatives.

I did not find the "same" thing in a proper size. As I said, I can opt for something totally different, which will fit in size, but I will be sad.

The YouTube videos make it look straightforward. But that's with a big investment in a shop and materials, and a lot of experience doing it before. The first sink those guys made wasn't like the video.

That is obvious, mastery takes practice, and material (and money) waste. I have limited experience with hand crafting smaller items (just hobby), and I know that things can get difficult quickly.

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Other notes:

• all walls are made of steel-reinforced concrete;
• the relevant walls (the one behind the sink and the one with the door) are only 8cm thick;
• I am very aware that creating a sink from epoxy is not a trivial task; that is why I did not ask first: "can I transform ruined cured epoxy into fresh epoxy?";
• I only need to create one piece; no need to worry for any marketability;

Answer 1

A sink like that is more complex than it appears. The factory that makes it has invested in precision molds that get reused to make it cost effective. There are hidden parts like the overflow plumbing and mounting, and considerations like making water-tight seals with standard plumbing components. There aren't really "secrets" to making it with the right structural characteristics, just a lot of engineering design and prototyping. Reproducing that (and getting a result that looks like a commercial product), would be a challenge even for a pro.

Your idea of making sections, adding an epoxy coat, and gluing them together is the kind of thing that might be used to make a prop that looks like a sink (it might even be how the "concept" model was made). It wouldn't look professional up close, and it would be tough to meet the structural requirements and have it hold up long-term.

People do use a somewhat related approach to make models out of fiberglass. They create a form with the shape, cover it with fiberglass cloth, then saturate the fiberglass with epoxy. The sink could probably be made that way as a whole unit. People make things like custom car bodies that way. It would take some experimenting, and a lot of "cleanup" and finishing work (the same work that goes into making a car body that looks like a finished product).

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Edit: an update to the question clarifies that the walls are concrete, so the following portion of the answer, which assumed wood framing, isn't applicable. I'll leave it here just in case another reader is in a similar situation.

If you really need to have that sink, altering the walls or door may be more practical. Those kinds of renovations aren't insanely expensive, the materials are readily available, and if you aren't skilled yourself, you can contract it out and the marketplace is competitive.

The potential solutions depend somewhat on your local building codes, but there are at least three approaches I can think of to gain 5 cm:

• Replace the door with a narrower one using the existing wall framing. That might even be a relatively simple task with little to repair.
• Reframe the doorway area of the wall to shift the door farther from the sink.
• Reframe the wall behind the sink to create a bump-in that the sink fits into. If that wall is not load-bearing and the construction is drywall over wood framing, you may be able to turn the studs sideways to make the wall thinner. With lumber in the US, that gains you two inches, which is your 5 cm. You might be able to gain a little more by using thinner drywall. It might even be practical to steal a little space from the adjoining room and bump back that section of wall (basically remove that portion and build a new wall a little farther back).
• Bathroom doors typically open into the bathroom except for "Jack and Jill" bathrooms shared between two bedrooms; those open into the bedrooms. It might be possible to flip the door around so it opens out. However, that would leave the sink and vanity sticking into the doorway. Even if that isn't against the building code, it will look pretty strange. It might even affect you when you go to sell the apartment, so it isn't a good alternative.

It might be worth talking to a carpenter to get input.

Answer 2

Changing the door is going to be much easier than making a sink/basin from scratch. By far the simplest way is using a pelmet and sliding door on the outside of the bathroom.

However, if you are convinced that this will not guarantee privacy or confine possible odours to the bathroom, you might want to use a bifold door. There are both central and side locking versions, and they fit a standard door opening just as closely as a standard side-hinged door. Something like this ....

Answer 3

Large items are not made with epoxy; they may possibly be made with epoxy with very substantial additions of fiberglass and minerals like limestone. The great majority of sinks are made with polyester filled with fiberglass and minerals. If you can find a local producer, he could make a custom sink for you. It may not be expensive, partly because he may have molds pretty close to what you want. When I visited the shop that made our 12 ft. long sink with two angles, it was a routine job. On reconsideration, yours is a standard "custom" sink, nothing out of the ordinary if you find a local producer.