Polishing Polycarbonate: The Complete Guide

Polycarbonate as a material is known for its durability and excellent resistance to impact.

However, a small scratch on polycarbonate material can affect its entire aesthetics.

What’s more, it creates room for more damage to occur.

As such, care needs to be taken to ensure that polycarbonate surfaces stay smooth, shining and long-lasting.

Polishing in this regard is an excellent solution to help rid this popular plastic off dulling, discoloration and scratches.

Besides, when fabricating polycarbonate, most methods don’t give a smooth finish.

Polishing helps to smoothen edges and surfaces after fabrication.

In today’s guide, therefore, I am going to help you learn how to restore and maintain the look and feel of your polycarbonate surfaces, through polishing.

But before that, let’s define polycarbonate polishing.

What is Polycarbonate Polishing?

Polycarbonate polishing is the process of smoothing the surfaces of a polycarbonate material.

The purpose of polishing is to help restore the material’s shine.

This is after it has been affected by dulling, discoloration, chemical erosion, scratching,etc.

https://youtu.be/nphRdvAUl9c

As I said to you earlier, polycarbonate is known to be a profoundly impact resistant material.

But even so, it is still susceptible to elements that can make it lose its appeal.

As such, one of the approaches that users can take to renew the restore the look and feel of polycarbonate is by polishing.

Benefits of Polishing Polycarbonate?

The many varied uses of polycarbonate have made it a ubiquitous material.

Its transparency, high resistance to impact as well as to heat are the primary reasons for its popularity.

If you look around you, most of the helmet visors, windscreens, eyeglass lenses, and windows, that you see are made of polycarbonate.

Even greenhouses and roofing sheets are made using it.

Now, although it’s resistant to impact, the transparent and shiny gleam of polycarbonate will eventually start to dull with extensive use.

It will especially get worse if you neglect to care and maintain polycarbonate items around you.

Scratches, scuffs, chemical erosion, need to be cleaned out to maintain polycarbonate surfaces in good condition.

It is because of this that periodic polishing is beneficial.

Before and after polishing

Before and after polishing – Photo courtesy: ENF Plastics

It will help to maintain the general aesthetics of your polycarbonate items as well as ensure their longevity.

So don’t overlook a slight scratch on the material, it could be the beginning of more expensive damage.

Also, as I’ve already told you, certain fabrication techniques don’t leave off a good finish.

You’ll to do some polishing after fabrication to help achieve that clear, smooth and shiny finish of your work pieces.

That said, allow me to explain a few methods that you can use to polish your polycarbonate surfaces.

Methods of Polishing Polycarbonate

Well, when it comes to polishing polycarbonate, you have a few options available for you.

Here’s a detailed guide on several methods of polishing polycarbonate that you might find useful:

Vapor Polishing Polycarbonate

A quick and effective way to vapor polish polycarbonate is through vapor polishing.

Vapor polishing also known as solvent polishing is the more popular method of a glossier and smoother surface finish.

The method is more prominent in applications that require high levels of transparency,i.e., in optical lenses, windscreen and laboratory equipment.

So how does it work?

Well, this method uses a chemical vapor that heats the rough surface causing it to flow, thus clearing out any roughness and dulling.

Note however that although highly efficient, vapor polishing requiresa high level of skill and experience.

It is because of this that I am going to share a simple step by step guideline on how to vapor polish polycarbonate.

Step by Step Process

For this project, you’ll need the following items.

  • Chemical solvent like Weld-ON 4 which is more popular in this regard
  • Heating equipment,e., kettle
  • Breathing a respirator or mask
  • Gloves

To polish, you need to first, gather all your supplies and assemble them in a controlled area.

Next, prepare the polycarbonate surface that you want to polish.

Once you’ve all these ready, begin by heating the chemical solvent in a kettle.

Make sure that it heats to a boiling point.

Now spray/direct the resulting vapors onto the polycarbonate surface gradually until done.

You will notice that each area you spray gets clearer and smoother.

This is because the vapor melts it causing it to flow thus smoothening out any roughness and clearing scratches.

And, as the melted surface solidifies it becomes clearer and glossier.

That’s it.

Remember though that this process shouldn’t be performed with a blank mind.

You need to know the right way to do it otherwise it could become dangerous.

Also, you should sand the surface before polishing as the vapor works at a microscopic level.

It doesn’t get rid of large cuts or scratches as efficiently as you would want it to.

Vapor polishing

Vapor polishing

Advantages of Vapor Polishing

Vapor polishing has very many benefits.

To mention a few;

  • It is very quick and efficient
  • Helps to reduce surface roughness
  • Improves the optical clarity of materials

Disadvantages of Vapor Polishing

Like everything else, vapor polishing has it cons.

These are:

  • It can be hazardous. The solvent fumes are highly toxic. As such, one must wear a breathing respirator or mask when performing this process.
  • Dues to the hazardous nature of the process, it must be done in a controlled environment with little no risk
  • It requires professional experience
  • Accessing the chemical solvent tends to be difficult as most of them like Weld-on 4 is restricted in most localities
  • After vapor polishing, an annealing process must be done to prevent the surface from post stress cracking.
  • It is expensive is a very effective method of machining a smooth and clear finish.

Please note that despite its disadvantages, vapor polishing is a very effective method of making your work piece clear, smoother and shiner.

You need to observe the right procedure and precautionary measures.

Buffing Polycarbonate

Polycarbonate buffing is the act of polishing the material to enhance its shine and attractiveness.

You see, over time, polycarbonate surfaces lose their shine regardless of how well they’re maintained.

And, the good thing is that you don’t have to get rid of your polycarbonate surfaces just because of a few nicks and scratches.

That would mean that you get a whole new replacement which would be rather expensive.

A less messy and inexpensive option would be to buff the polycarbonate surface.

If done correctly, buffing can help you achieve that refined new look on your polycarbonates once again.

Wondering how you can buff polycarbonate?

Don’t worry I’ll show you.

Step by Step Process of Buffing Polycarbonate

What you’ll need

  • Buffer
  • Loose abrasive
  • Protective clothing,e., gloves, goggles
  • Fine grit sandpaper

Before you start the buffing process, sand the work piece surface first.

You see to achieve greater buffing results; you need to sand your work piece to remove deep scratches.

Use fine grit sandpaper for this and sand the surface evenly.

Once you’re done sanding, use a damp cloth to clean up the surface further.

So now your material is ready for polishing.

For the actual buffing process, you will use a buffing machine.

There different types of buffers.

So make sure that you’re using the right buffer for your application.

Note however that most buffing machines come with some mops attached to it.

Some come with wheels in place of the mops.

So to buff, take the machine and apply a loose abrasive on the mops/wheels.

Buffing polycarbonate sheet

Buffing polycarbonate sheet

Turn the switch on and carefully press the work piece against the mop moving back and forth to ensure even polishing.

When buffing, do not hold the work piece in one place as you may end up destroying the mop.

Please note, other buffers will require that you press the mop against the work piece moving it back and forth for even polishing.

Just read the user manual to find out how your unit works and follow the steps given to the later.

Also, the abrasive/polish/buffing compound you use will significantly define the results of the process.

So make sure that you use the right compound for the process.

Another thing, before switching the machine on, you need have a firm grip of it.

This will help ensure your safety and that you carry out the buffing process properly.

Advantages

  • Buffing helps to refinish newly fabricated polycarbonate surfaces particularly
  • It also helps to renew the look of damaged surfaces
  • Helps to create reflective polycarbonate surfaces
  • Creates an even and leveled finish
  • It is inexpensive and efficient

Disadvantages

  • Buffing doesn’t work effectively for severely damages surfaces. It might get rid of a few scratches but won’t be able to restore the surface’s original look
  • Compared to vapor polishing, buffing doesn’t give a tremendous shiny look

Chemical Polishing Polycarbonate

Chemical polishing works as excellently as vapor polishing.

It is a method of choice for most polycarbonate polishing applications.

How does it work?

Well, chemical polishing involves the use of a chemical polish to help replenish the look of a polycarbonate surface.

Chemical polishing polycarbonate

Chemical polishing polycarbonate – Photo courtesy: CARVILLE PLASTICS

The polish works by passivation of the surface of the material.

The effect of this is that it causes a direct smoothing and polish formation along with the parallel dissolution of the upper layer of the polycarbonate material.

To chemical polish polycarbonate, here’s what you’ll need;

  • Chemical polish mostly methylene chloride
  • sandpaper
  • Protective clothing,

The Process

Begin by preparing your work piece.

You should do this by sanding the surface to remove any scratches.

You’ll then wipe off the surface using a wet piece of cloth.

This will also help to remove any formed debris on the surface.

After this, you should apply the chemical you’re using and give it time for passivation.

After it has cured, run the polished surface through some water to avoid cracking due to the post-polishing stress.

Advantages

  • Chemical polishing is less labor-intensive and requires very minimal energy
  • It is also very effective in restoring the smoothness and shine of polycarbonate surfaces

Disadvantages

  • The process of chemical polishing is quite complex
  • The chemicals used in this process are usually highly toxic and combustible.
  • It is expensive compared to the other methods that we’ve mentioned
  • If not done correctly, the chemicals can erode your work piece.

Sanding Polycarbonate

Sanding is perfect for polycarbonates that are in terrible condition,i.e., with deeper scratches/cuts.

With the sanding polycarbonate technique, you can easily get rid of messes without having to worry about big repairs or replacing the polycarbonate.

Here is the process of sanding polycarbonate:

What you need

  • Several grades of sandpaper,i.e., 400, 600, 800 and 1000 grit sandpaper.
  • Water
  • Wiping cloth
  • Gloves
  • Apron
  • goggles

The Process

The first thing you’ll need to do is to prepare your work

piece.

Wet the work piece with a little bit of water.

Don’t use too much water as this can compromise the efficiency of the process.

Your next step is to sand the surface using the different grades of sandpaper progressively.

Using the lowest grits and paper, begin by rubbing circles over the area of the polycarbonate that needs sanding.

This is to help get rid of more prominent scratches.

Take your time and concentrate on accuracy not speed.

While you may be looking forward to getting your polycarbonate polished, making a mistake could cost you more time, energy and even money.

So, as you continue to sand, add more water to the surface.

This will help keep debris from building up.

It will also help keep your sandpaper lubricated.

The best way to do this is to use a spray bottle.

It will allow you to mist just the right amount of water on the surface.

Keep going with this process until your surface is clean and smooth.

Remember that you need to use the sandpaper progressively.

Start with the coarsest going forward to the finest grit you have for a smoother finish.

Also, change the sanding technique from heavy in the beginning to light sanding towards the end of the process.

Sanding polycarbonate

Sending polycarbonate – Photo courtesy: Instructables

Advantages of Sanding Polycarbonate

  • sanding helps to get rid of wild scratches and cuts on surfaces
  • it helps to create smooth surfaces and edges in polycarbonate materials
  • Sanding is cheaper and effective in its merit.

Disadvantages of Sanding Polycarbonate

  • Sanding is labor intensive
  • It is also time-consuming
  • Sanding doesn’t give a clear finish, so it’s not the best method when you’re looking to achieve optical clarity

Well, these are the three most effective methods of polycarbonate material.

These three methods will work in the different application which has a certain degree of effectiveness above the other.

So make sure that you choose the methods that best suits and your need and application.

Talking of choice, allow me to show you three scenarios where each of these three methods is suitable.

Polishing Polycarbonate Edges

Cutting polycarbonate is one of the ways of fabricating this remarkable material.

And this is done for reasons that I believe are quite obvious.

Now, while cutting may help you achieve the desired size of material for your project, it tends to leave you with a rough cut edge.

The level of the ruggedness of course often depends on the cutting approach you use.

Luckily though, polishing can help smoothen out cut polycarbonate edges to give them a smooth and clean finish.

Polishing helps to give a professional and aesthetic finish.

So to smooth out serrated, rough, and rugged polycarbonate edges, buffing works best.

To be precise, you should use wheel buffing.

This method uses the kind of buffing machine that comes with wheels.

These machines are known to be quite effective at their job.

They leave your edges smooth and clean.

Polishing edges

Polishing edges – Photo courtesy: ESHEET

Note however that this buffing machine is expensive.

So if you’re sure you’ll be using it more often, then ask in DIY shops around you or shop online for something that you can afford.

Otherwise, find a workshop that can let you use theirs at a fee or simply hire one for the moment.

This will be less costly.

Sanding also works well for polishing edges.

Wet sanding, in particular, works best.

So this means that you need water as well as waterproof sandpaper.

Please note that sanding is equally efficient at polishing polycarbonate edges, it consumes lots of time and energy.

So using a buffing wheel may the best alternative if you don’t have the time or energy for sanding.

Plus, comparing the two, buffing gives a finer finish.

Polishing Polycarbonate Surface

Unlike edges, we polish polycarbonate surfaces for various reasons.

These include to improve its optical clarity, to remove minor scratches and sometimes to get rid of erosion.

In this regard, vapor or solvent polishing as it is also known tends to work best.

Mainly, if you’re polishing medical/laboratory equipment, eye-wear lenses or windscreens, vapor polishing will give you result that you’re looking for.

Polishing to remove scratches from surface

Polishing to remove stretches from surface

Remember though that for surfaces, vapor polishing doesn’t get rid of deep scratches.

You should only consider it if your purpose is to achieve optical clarity.

Besides, the method can get quite dangerous if done incorrectly and if proper safety measures are not taken.

Polishing Scratches Off Polycarbonate

The perfect way to get rid of scratches regardless of magnitude is by chemical polishing.

The way chemical polishing works is enough to fill up those cuts and scratches on your polycarbonate material.

Besides, it will also leave you much cleaner and shinier finish than before.

Like vapor polishing, chemical polishing also requires a bit of skill and experience.

It also requires one to take certain safety precautions.

Otherwise, the chemical itself and the fumes from melting the polycarbonate can be hazardous.

Removing scratches

Removing scratches – Photo courtesy: MIG WELDING

Chemical polishing is also expensive as well as complicated.

In all this,therefore, you need to do enough research on what method best suits your application.

Also, ensure that you understand the process along anything else that maybe useful.

FAQs on Polycarbonate Polishing

With all that’s been said in this guide, I know you still have questions on polishing polycarbonate.

Well, don’t worry, I am going to provide answers to some of the common and critical questions on this topic.

So let’s get right to it!

1) How long does vapor polishing take?

Well, naturally, vapor polishing is the fastest of all polycarbonate polishing process.

Once the vapor is directed to the material, the work piece becomes visibly clear and smoother in just a few seconds.

You don’t need to expose the material to the vapor longer to get better results.

More prolonged exposure can damage the material.

Besides, surfaces solidify immediately after exposure.

This means that you can use the material immediately after vapor polishing.

2) Compared to buffing, sanding and chemical polishing, is vapor polishing cost effective?

Well, the vapor is comparatively cost effective in its specific applications.

This is especially true of applications that require optical clarity in materials.

Transparency, note, is usually very essential in polycarbonate applications.

The solvent vapor used in this process can penetrate the deepest cuts and scratches and make them visibly clear in seconds.

Something that buffing or even sanding can’t achieve.

3) Do the materials change dimensionally after vapor polishing?

Well to some extent yes.

The dimensions do change especially if the polished material had excessive stress before polishing.

If it had stress before polishing, its dimensions could change if during the annealing process.

4) What is annealing?

It is a process performed right after vapor polishing to relieve any stress from the material.

You see when polished surfaces solidify, they could become too hard and crack.

The annealing process help to prevent cracking from happening.

5) Flame polishing works on acrylic, can it work on polycarbonate?

To be honest, flame polishing doesn’t work so well on polycarbonate.

You’d have to dry the polycarbonate to get rid of any moistures thoroughly.

Otherwise, you’ll have to deal with lots of ugly bubbles as the polished surface begins to clear.

6) What measures should you take to ensure the best vapor polishing results?

Not much I haven’t already mentioned.

However, you most importantly need to ensure that the surfaces you want to polish are super clean.

They shouldn’t have any dirt, debris, grease or oils as these can jeopardize the aftermath of the process.

Also, if you’re finishing a machined material, you need to ensure that your machine finish is squeak.

Don’t vapor polish surfaces that still have tool marks or anything like that as polishing won’t get rid of them?

7) How do I remove oil, or grease from polycarbonate surfaces?

To remove oil or grease from polycarbonates, rub the surface gently with a soft clothed damped in isopropyl alcohol.

If the surface had lots of oil and grease, you could follow up with light washing using mild soap and water.

Don’t use any abrasive cleaning agents as these can scratch or haze the material.

8) My polycarbonate windshield is quite Smokey how do I make it more transparent?

Buffing can help restore the clarity of your windshield.

Following the guidelines I’ve provided on this guide, you should be able to buff the windshield to its original transparency.

Just make sure that you use the right buffer and a suitable compound for this.

A trick is to first test out a small section of the windshield before proceeding.

9) I’ve just cut a polycarbonate tube, but I don’t the cut finish, can I sand it?

Absolutely!

Sanding a cut polycarbonate tube will give you superior results.

Light buffing for the cut edge will also give you a smooth and clean finish.

10) How should I store polished polycarbonate surfaces?

Polished polycarbonate materials should be stored in a well-protected, ventilated area with no exposure to harsh weather.

If you have to store the material in a natural environment, make sure that you cover it with a heat reflecting opaque cover.

Conclusion

From this guide, it’s quite clear that while polycarbonate is highly resistant to impact and heat, it is still susceptible to destructive elements.

It can dull, get scratched or scuffed.

Luckily, refining the look of polycarbonate is easy as there are many ways to do that.

All you need to do is ensure that you choose the right method for your application.

You also should employ the right precautions when polishing polycarbonates.

That’s it.

If you have any more questions or topics about this topic, feel free to share with us in the comment section.

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