Toilet      04/09/2019

The technology of restoring old bathtubs at home. Restoration of bathtubs with liquid acrylic - a way to restore

Quite often, you can encounter a situation where the bath fails, but the possibility of its high-quality replacement in this moment does not exist. What should be done in this case? If there is not enough money to buy a new bathtub, or if there is no possibility of dismantling this structure, a situation inevitably arises that requires the restoration of a damaged bathtub. We will talk about this procedure in our article.

So, the restoration of the bath - where does it start and what is needed to carry out this process? Bath restoration can be carried out using several methods, each of which has its own advantages and disadvantages.

The most optimal and fast way to restore a damaged bath - to make a special insert in it from a special sheet of acrylic. The size of such a sheet should completely repeat the size of the bathroom itself, but its thickness should vary between 5-7 mm. An acrylic sheet is attached to the bathroom using a construction polyurethane foam. After carrying out such a procedure, the bath should dry for seven hours, and after that the structure can be used for its intended purpose. The main disadvantages of this method of restoration are the instability of the acrylic insert to strong mechanical damage, the possibility of detachment of the glued acrylic sheet from the base of the bathtub or incorrect selection colors(in this case, the acrylic insert will stand out ugly against the general background of the bathroom).

The next way to restore a damaged bath is to completely replace its enamel. This method requires much more material costs. At the same time, before carrying out a new enamelling of the bath, care must be taken to proper preparation designs for this procedure. First you need to remove from the bathroom old layer enamels. To do this, use sandpaper. Then the cleaned surface must be checked for potholes and cracks. If there are any, it is important to properly process them with special putty compounds for bathtubs. Then it is necessary to degrease the surface of the bathroom. Before enameling, the bath must be well heated so that the enamel layers lie evenly and are perfectly absorbed. Then you can proceed directly to enameling. For this, an enamel solution and a special painter's set are taken - several brushes and a roller. Enamel is applied in several layers on the bathroom surface, and each layer should be evenly distributed over the surface of the bathroom. After applying all layers of enamel, its thickness on the bath should be no more than 1.5 mm, and not less than 0.5 mm. Such a coating can last a short amount of time (approximately 7 years). The main advantages of this method of restoration is the ability to choose an unusual color (the color possibilities of bath enamel are quite diverse). Among the disadvantages of this method are the low quality of the enamel, the short life of the enamel coating and the appearance of roughness on the surface of the bathroom after enamelling.

Restoration of bathtubs high level can be carried out by using a special universal material called staracryl. This tool has positive characteristics of strength and quality. Staracryl refers to a wear-resistant and impact-resistant variety of enamel, which is based on liquid acrylic. Restoration of the bathroom with this tool is in many ways similar to the restoration of ordinary enamel. The only difference is that liquid acrylic is not applied to the surface with a brush or roller. It is simply poured onto the walls of the bathroom, trying to completely cover them. The rest of the staracryl just drains into the drain hole of the bathroom. This treatment allows you to get a very smooth and shiny bathroom surface, without any roughness. However, this method also has a significant drawback - staracryl is very susceptible to mechanical damage and scratches, therefore, it is necessary to be especially careful with a bathtub that has such a coating.

I would also like to add that the duration of use of the coating in your bathroom will depend not only on the chosen means for its restoration. Much here depends on the company that performed the restoration of your bathroom. The more experienced the experts were, the longer the coating in your bathroom will last. Also, when restoring the bathroom, pay attention to the fact that you should not use abrasives to clean the bathroom surface. They will scratch the surface and this will quickly lead to damage to the surface and failure of the bath.

Over time, the bath loses its attractive appearance. Smudges and traces of rust appear, gloss disappears, it becomes rough to the touch. Everything says it's time old bath change. And these are not small expenses. In addition, when replacing a bathtub, you cannot do without renovating the entire bathroom, and small expenses will turn into medium, or even large ones. But there is an alternative - do-it-yourself bath restoration. Presented on the market a large number of materials with which you can independently update your bath with proper quality.

Bath restoration methods

Now there are three methods for restoring old bathtubs:

1. Restoration of the enameled surface of the bath.

2. Restoration with liquid acrylic.

3. Restoration by insertion.

Method 1: ordinary enameling

Cast iron and steel enameled bathtubs are the most common types of bathtubs in our apartments. They are produced in accordance with GOST 18297-96, which has been in force since 1997. According to this GOST, the guarantee for bathtubs is 2 years. But as practice shows, the enamel on them lasts no more than 10 years of use.

Enamel on baths in the factory is applied quite simply. First, the outer surface is heated red-hot, then inner surface the enamel powder is sieved and kept for some time to sinter the powder with the metal. Heat the outer surface again until the powder is melted. The result is a smooth, glossy enamel finish. It is clear that at home this method of restoration cast iron bath, as well as steel, is not good.

Why does enamel usually wear out?

The wear of the enameled surface occurs as a result of two factors:

  • The use of cleaning products containing abrasive powders or substances with chlorine inclusions.
  • The use of chemical reagents in the cleaning of water supply networks.

As a result of many years of exposure to these factors, the enameled surface of the bath becomes thinner, rougher and begins to rust.


Restoration of the enameled surface

Do-it-yourself enamel restoration is a fairly simple process. It consists of two stages: surface preparation and application of a new layer of enamel.

What will be needed for work?

You will need the following tools and materials:

  • electric drill with a nozzle in the form of a grinding wheel;
  • abrasive powder;
  • sandpaper;
  • rust converter (for example, "Tsinkar");
  • degreaser (for example, "Nefras");
  • lint-free napkin;
  • natural bristle brushes or spray;
  • respirator and gloves;
  • enamel, preferably two-component (enamel plus hardener).

Preliminary step: surface preparation

Very milestone. The more thoroughly the surface of the bathtub is cleaned, the better the new enamel layer will be.

  1. sprinkle the old enamel with abrasive powder and clean it off with sandpaper or a grinding wheel mounted on an electric drill;
  2. treat areas affected by corrosion with a rust converter, hold for half an hour, then clean with sandpaper;
  3. wash off the enamel and crumbs with water;
  4. thoroughly treat the bath with a degreaser using a lint-free cloth;
  5. fill the bath hot water and let it warm up for 10 minutes;
  6. drain the water and wipe dry with a lint-free cloth; make sure that there are no lint or other foreign elements on the surface.

The main stage: applying enamel

  1. according to the manufacturer's instructions, mix enamel and hardener in a certain proportion and mix thoroughly;
  2. apply the first layer of enamel with a brush or spray;
  3. withstand a certain period of time according to the instructions;
  4. apply a second layer of enamel.

This completes the process of restoring an enamelled bath with your own hands. It is advisable to withstand at least a week before the start of the operation of the bath. This is how long it takes for the enamel to fully polymerize.

The service life of the new enamel will be about 6-8 years.

Method 2: bathtub restoration with liquid acrylic

This method of bath restoration appeared relatively recently, thanks to the emergence of a special material - glass.

What do we restore?

Glass acrylic is a two-component acrylic material designed specifically for bathroom renovations. It is acrylic itself and a separately supplied hardener. When acrylic and hardener are combined, the polymerization process begins, and when applied to the surface, the composition turns into a high-quality acrylic film with a thickness of 4 to 6 mm.

Advantages of glass

Stakryl has three remarkable properties that help it quickly and effectively restore the bath:

1. Viscosity

Optimally matched coefficient of viscosity of glass helps to make an acrylic coating with a thickness of 4 mm on the walls of the bath and 6 mm on its bottom without much effort.

2. Fluidity

The fluidity effect allows glass to independently envelop the surface of the bath and lay down in an even layer.

3. Delayed polymerization

Thanks to this quality, you can calmly and relatively comfortably carry out work on the restoration of the bath, without fear that the acrylic will harden too quickly.

After curing, the acrylic surface has mechanical and impact strength far superior to the acrylic inlay or enamel layer.


Work performance technology

The technology for restoring bathtubs with liquid acrylic is even simpler than the enameling process and is as follows:

1: Surface preparation

This stage does not differ from the restoration of the enameled surface. Repeat the same steps. Then disconnect the siphon and place a container under the bathtub drain, where excess acrylic will drain.

2: Apply liquid acrylic

  • prepare the acrylic mixture according to the manufacturer's instructions;
  • slowly pour the finished mixture onto the upper edge of the bath, as soon as the jet reaches the middle, we begin to smoothly move the jet of glass along the perimeter of the bath;
  • when the circle closes, repeat the procedure, starting from the middle.

The poured restoration process must be continuous, for this you need to take a glass container of a suitable size. It’s not worth saving - it’s better to pour out a little more acrylic than it will be lacking, the excess will go into the container under the drain hole.

Acrylic is polymerized, depending on the type, from one to four days. Choose a glass with a long drying time, in which case the acrylic surface will be of better quality.

The service life of the restored bath will be about 20 years.

Method 3: bathtub restoration with an insert

The simplest, but also the most expensive way of restoration is the installation of an insert. In addition, it is impossible to completely restore the bath with your own hands using this method, since the liner is made in the factory.

There is an option to order the manufacture of an insert for a specific bath at the enterprise, and install it yourself.

Insert installation technology is as follows:

  1. thoroughly clean and degrease the surface of the bath;
  2. insert the manufactured liner into the bath;
  3. check the correctness of the docking of the drain holes;
  4. cut the liner along the wall tile line;
  5. apply special glue to the inner surface of the bath and the outer side of the liner and dock them;
  6. joints are additionally sealed with silicone.

After installing the liner, pour into the bath cold water and last for days. After that, the restored bath is ready for use.

The insert will serve you up to 10 years.


How much will a bathroom renovation cost?

In conclusion, we will comparative analysis the cost of restoring the bath, based on the methods discussed above.

Bathtub enameling

The cost of high-quality enamel "Reaflex 50" produced by the Finnish company "Tikkurila" is 550 rubles per 1 kg. The Russian set for restoration "Svetlana" costs 750 rubles. As a result, you will have to pay 1300 rubles.

Cast restoration

If you buy a set for restoring a bathtub with liquid acrylic, for example Plastall, it will cost about 2000 rubles. By the way, it has everything you need to independent work, even a CD with a video lesson.

Acrylic liner

The cost of the insert itself and polymer glue ranges from 2800 to 3000 rubles.

The best option is the poured restoration method, in which you get a beautiful and durable coating for little money. Moreover, any of these methods is several times cheaper than buying and installing a new bathtub.

A bath is an invariable attribute of bathrooms, and pleases the eye with its cleanliness and whiteness. This is at best, otherwise the bath, shabby and scratched, with rusty spots and smudges, becomes a source of bad mood and irritation. Yes, psychologists have noted this important feature in people prone to depression.

And this is not surprising, because at the sight of a clean and elegant bath, an association immediately arises with warmth and bliss, relaxation and pleasure, which invariably accompanies lovers of taking a bath.

Previously, in the manufacture of baths, they did not spare cast iron, covering it with a layer of enamel. Such baths were eternal, but heavy. The enamel cracks and stains over time, but the tub itself remains intact. It is possible to change an old bathtub for a new steel one, but we understand that for this we need to tear it off the wall, damaging the tile. And another question, will a thin-walled new bathtub be better than the old one?

Due to the fact that a new bathtub is quite expensive, and the old one is no good, the question arises: how can an old bathtub be restored? Thanks to modern technologies this can be done easily and simply. The restoration uses liquid acrylic - a material with which it became possible to restore bathtubs from any material.

More recently, the restoration of old bathtubs was carried out by covering the walls with a layer of enamel. The new modern technology, using liquid acrylic as a material, is distinguished by its impact resistance and increased wear resistance.

The material itself has an important property - good fluidity, which allows the method of pouring acrylic to effectively apply it to the walls of the bath. Restoration of the bathtub with acrylic provides a fairly uniform coating of the walls, filling existing chips, cracks and other possible defects.

Restoration of bathtubs with liquid acrylic has obvious advantages:

  • In time, this may take only a few hours.
  • A new refurbished bathtub has a minimum 2 year warranty.
  • During the restoration, it is not required to dismantle spare parts from the bath.
  • At least 10 or even 15 years of good bath condition with careful use.
  • The new bathtub becomes warmer due to the acrylic layer, which has good thermal conductivity.
  • The coating will be smooth and even, without roughness and bubbles.
  • Over time, the material does not darken or turn yellow, remaining glossy and snow-white.
  • Acrylic does not break from impacts, does not wear out and does not scratch.
  • The material has no odor.
  • Acrylic is not subject to corrosion and influence of acids and alkalis.
  • And finally, in terms of money, restoring an old bath is cheaper than buying new equipment.

Restoration of bathtubs with liquid acrylic is carried out according to the technology of the world's leading acrylic manufacturers. Of all the brands of acrylic, they prefer to use brands that are of unsurpassed quality and fully meet international standards.

These include:

  • Du Pont (France);
  • Byk Chemie (Germany);
  • Evonik (Germany);
  • Dow (Germany).

Restoration of an old bathtub can also be carried out using an acrylic liner, but when used, there were cases when water leaked under the liner, and the bathtub had to be restored again. This could be due to the negligence of the craftsmen themselves performing the work, as well as if cheaper material was used during the restoration.

It should be noted that the technology for obtaining a flawless new bath, as well as fast and comfortable work masters are directly related to the properties of acrylic. The fact is that acrylic has fluidity, viscosity and the ability to harden slowly, which allows you to cover an old bath with a thickness of 4 to 6 mm on the walls and bottom, respectively. Fluidity and viscosity allow acrylic to slowly drain and spread evenly under the influence of gravity.

How much can you save on acrylic on an old bathtub? At first, the cost of acrylic is really scary, but if you put everything on the shelves, then the following picture is learned:

  • A new bathtub costs, depending on the material, from 10,000 to 15,000 rubles.
  • To simply disassemble the old bath and take it out, you will need at least 2000-4000 rubles.
  • The installation of a new bath will require another 2000-4000 rubles.

Total - it turns out that we have to spend from 14,000 to 23,000 rubles just to buy a bath and replace it. Add to this the cost of the tile that was damaged and the cost of the tiler's work. Then the cost of covering the old bathtub with acrylic (from 3,500 to 3,900 rubles) is not only inexpensive, but also very profitable.

Liquid acrylic bath restoration technology

Restoration of bathtubs with liquid acrylic requires careful preparation for repair work. The surface to be coated must be completely clean, and for this, the old enamel is removed with an abrasive material. You can also do it manually, which is quite difficult and takes a lot of time.

Modern technologies suggest doing this with a drill with a special nozzle in the form metal brush. This technology has a significant disadvantage - a lot of noise and a lot of dirt and dust. But there is a huge plus - the bath is cleaned in this way in about 20 minutes.

Dirt and dust are thoroughly washed off into the sewer, and the surface is treated with a special solvent that degreases the walls of the bath. To prevent the acrylic from getting into the siphon, it is removed and after that the bath is ready for coating.

The technology has one more advantage - old cracks, chips, various roughnesses and places of other damage do not need to be leveled beforehand, since viscous and fluid acrylic will cover the walls of the bathtub with an even layer when it drains. After the acrylic has drained, the bathtub will have a perfect look and a leveled surface.

Restoration with liquid acrylic has its own characteristics. Under the drain hole, at the location of the siphon, a container is installed so that excess acrylic drains from the walls of the bath. Then liquid acrylic pours out in thin streams along the edge of the rim, smoothly moving around the perimeter of the entire bath. When applying acrylic, care must be taken to ensure that there is enough acrylic, excess residue flows into a container under the bath.

As soon as one circle ends, without stopping, the second circle begins and so on. All irregularities do not need to be corrected, since they diverge themselves and do not remain on the walls. Thus, liquid acrylic spreads in circles around the bath until the bottom is reached. Then it remains only to wait until the acrylic dries.

The material dries, as a rule, for several days. Everything will depend on the layer and the degree of damage to the bath. If the old bathroom was badly damaged, it is poured with a thicker layer of acrylic, and such a surface dries for 3-4 days. If the damage to the walls was minor, and an ordinary layer of acrylic is worn, which dries for 1-2 days.

The time to complete drying also depends on the material, as there are quick-drying and long-drying acrylics on sale. The question is often asked - what material is better? On the one hand, in 1-2 days to receive new bath more tempting, but more even and stronger, is the acrylic that dries slowly and becomes covered with a thick layer.

This is not surprising, since acrylic has all the properties of cementing materials, which acquire their strength over time. So, for example, poured concrete is much stronger after 30-50 years than at the very beginning.

Rules for the operation and minor repairs of acrylic bathtubs

Ideally, if you don't drop anything or hit the tub, nothing happens. But in life it happens that a crack appears in the acrylic bath. It would be foolish to immediately call the repair team and use them to eliminate this defect. It just takes a little skill and patience to. These repairs can save you a lot of time and money.

Repair will require some tools and necessary material for coating (epoxy adhesive). And so that such defects no longer occur, it is necessary to remove all heavy objects from the bathroom in order to avoid a new crack or chip.

It may take your skill to make a do-it-yourself bath screen. Firstly, it is aesthetically pleasing, since the legs and bottom of the bathtub are not visible, and secondly, it can be a hidden niche for storing the same cleaning products.

And finally, before using a new bathroom, you need to know. Such a bathroom does not like abrasive powders and hard scratching brushes. Such cleaners can leave scratches on the walls of the acrylic bath. It is best to take care of such a bathroom by rinsing after each bath and wiping it dry, and use ordinary washing powder to disinfect and clean dirt.

Particular problems are caused by yellow spots or stains that can appear on an acrylic bath due to the increased rust content in the water. the best way is to install a filter to clean water from rust, well, if stains still appear, you can try to clean them with diluted lemon juice. Remember not to use acids or alkalis to clean the tub!

You may need knowledge and skill to install acrylic bath. This may be the case if you are doing repairs in the bathroom and bought such a bath. Acrylic bath light enough compared to cast iron, and you should have no questions about how, but more on that in another article.

Video instruction - Restoring bathtubs with liquid acrylic

Currently there are 3 ways to update old cast iron bath:

Bathtub enamel restoration.

Acrylic bathtub cover.

Installing an acrylic bathtub.

Before deciding which method to choose, it is worth evaluating the advantages and disadvantages of the methods. bathtub enamel restoration which you can read about in this article. The next step in surface restoration is to prepare old cast iron bath before coating (how to do this).

Now consider all 3 options for restoring the bath.

1. The mixture is directed clearly according to the instructions written on the package. It consists of enamel, hardener and dye. It should be kneaded slowly and carefully, avoiding the formation of foam.

The surface is covered with thin layers. It is best to use a brush with natural bristles, and in order to prevent bristles from coming out of it, you should first coat its base with ordinary enamel. Then let dry thoroughly.

3. After applying the first layer, it should be given the necessary time to dry completely. On average, it takes 30-60 minutes.

4. Then you can continue applying new layers. Their number varies from 4 to 7. The more layers applied to the old cast iron bath the longer it will last.

Respirators must be used when working with bath enamel, as it has a very pungent and pungent odor that can be harmful to health. It is also worth noting that you need to have new brushes and gloves in stock so that if necessary they can be replaced without interrupting work.

After finishing work, the bathroom is closed for 5-7 days, depending on the number of applied layers for bath restoration. The more of them were made, the longer the surface will dry out. You should try not to enter the bath during this time. Otherwise, dust particles can settle on the enamel and stick to it, which will make the surface uneven.

Fig. 1 Technology for applying enamel on an old cast-iron bath

This method is also called bulk bath. When applied, liquid acrylic spreads very evenly, thus forming an absolutely smooth and even surface.

The coating is made with a substance called stacryl. It consists of acrylic and a hardener made specifically for the surface of the bath. When applied, the composition is converted into a hard and durable coating with a thickness of 4 to 6 millimeters.

1. Liquid acrylic begins to be carefully applied to the sides of the bath, then, due to its viscosity, it independently begins to flow down the bath, thus forming a perfectly even coating.

2. Then the application is repeated in those places where the liquid acrylic has stopped flowing. Be sure to substitute any unnecessary container under the drain. It will collect the remains of glass, which, if necessary, can be reused.

3. If there are uncovered spots, in this case, using rubber spatula they are neatly covered with liquid acrylic, which accumulates at the bottom of the bath.

4. If necessary, the edges of the tub are also finished with a rubber spatula. One coat is more than enough. After finishing work, the room where the bath is located is tightly closed for 36 hours. This is the drying time for glass old cast iron bath. So DIY bulk bath is quite real.

Fig. 2 Acrylic bath coating technology

Before you start gluing the acrylic bowl inside the bath, it should be borne in mind that it must be inserted completely without all kinds of trimming of the sides. If this moment is neglected, then eventually, sooner or later, water begins to enter the cut edges and accumulate there. Because of this, the smell of sewage is formed in the room, and the inserted bowl begins to peel off over time. Therefore, do not neglect the dismantling of the bath, freeing all sides.

1. First of all, the liner is tried on in the bath in order to determine the place of drain and overflow.

If it is not possible to install the liner completely in the old cast-iron bath, then all excess edges are cut off and subsequently glued silicone sealant.

3. When the liner is fully fitted to the bath, it's time to apply the adhesive specifically designed for this purpose. It should be applied to the entire inner bowl old cast iron bath and on wrong side acrylic liner.

4. All edges of the joints are additionally treated with silicone sealant. This is done in order to exclude the possibility of water getting between the tub and the tab.

6. Then the drain and overflow system is installed. Then the bath is filled cold water and kept in this state for at least a day.

The result is a coating that is in no way inferior to a new bathtub.

In any case, when the expiration date of this product comes to an end, there is always the opportunity to give a second life to the bathtub in the form of a mini pond in the country, and how to do it, read this article.

Fig. 3 Technology for installing an acrylic insert in an old cast-iron bath

I wonder what will happen tomorrow? If ten years ago no one thought of restoring the bathtub in any other way than applying a second layer of enamel, now thanks to modern technologies it has become possible to install an acrylic liner in an old bathtub within a couple of hours or simply fill its inner surface with liquid acrylic . The result exceeds all expectations - you get an almost new bath, ready to serve you faithfully for at least another ten years.

If everything is more or less clear with an acrylic liner, then technology such as bathtub restoration with liquid acrylic looks rather vague and ambiguous. At least for those people who did not have to face it closely. And, having understood the process, everything becomes clear as daylight!

In fact, the technology itself using liquid acrylic is not complicated. More interesting from all points of view is the material itself used to restore the surface of the bath - "Stakryl".

Qualities and properties of glass - liquid acrylic for the bath

Glass is a material specially developed for the bath. That is why he has only those qualities that are necessary for convenient operation with it and obtain a high quality coating.

Firstly, the combination of three properties of the liquid composition, which makes it possible to make the work of the master fast and comfortable, is viscosity, fluidity and its ability to harden immediately. These qualities are very important: viscosity or density allows you to create a new coating with a thickness of 4 mm on the walls and up to 6 mm on the bottom of the bath. Due to the fluidity, the mixture is independently distributed under the action of gravity in a uniform and even layer over the entire surface of the bath, and the ability of glass to harden slowly helps in this not very fast process.

Secondly, a completely dry surface bulk bath withstands loads much higher than an acrylic liner or ordinary factory-applied enamel can withstand. Glass is almost impossible to damage. Unless, of course, you specifically set out to do this. It wears out for quite a long time and is practically not damaged during cleaning and household chemicals.

All this should be enough to opt for this particular technology for restoring an old bath - bathtub restoration with liquid acrylic.

We seem to have figured out the properties of glass, it remains only to find out how such a miracle coating is created as bulk bath.

"Pouring bath" technology - restoration of the bath with liquid acrylic

As elsewhere, before proceeding with the application of a new coating, it is necessary to carefully prepare the surface to be coated. Old enamel must be treated with abrasive material. Doing this manually is quite difficult and long, so they use a drill and a special metal brush for this purpose. There is a lot of dust and dirt, but the surface is quickly brought to the required state.

Dirt after stripping the old enamel is washed off, the surface is degreased with a solvent, the siphon is removed and the bath is ready for applying the glass coating.

The great thing about the "filling bath" technology is that you don't need to seal deep scratches and chips - spreading stakryl fills all the bumps and levels the surface of the bath to an almost perfect state.

What's next? And then we install a container under the drain hole - excess stacryl will drain into it, and proceed to apply liquid acrylic. We pour it onto the edge of the rim with a not strong stream and wait until the glass flowing down reaches the middle of the height of the bath, after which we begin to move the stream pouring from the bucket along the entire perimeter of the bath. We carefully monitor that liquid acrylic for the bath is in abundance. Let it be a little more - the excess will drain into the container under the bath.

The pouring bath operation must be carried out in a continuous process. Start pouring and do not stop until, after going in a circle, you close the ring. You don't need to fix anything - just mess it up. All streaks and influxes will disperse themselves. You just have to wait until the new surface of the bathtub dries.

And it dries from days to four. It all depends on what kind of glass you use - there is a quick-drying material on sale (after a day you can already use the bath) and a long drying one (the bath is ready for use after four days). Which is better? Better one that dries longer - the surface is a little better and stronger. Such are the properties of materials, and not only glass. For example, concrete gains its strength over 50 years.

And finally little advice for those who want to restore the bathtub with liquid acrylic, you should not dilute the material, thus achieving its savings. This will result in a thin layer of coating that will last for a very short time.