Search the web and you will find all sorts of crazy suggestions for repairing discs, including, yes… using a banana. There’s even some jokers trying to suggest using a microwave!

But these manual methods are fundamentally flawed because nothing can beat the accuracy of a machine when it comes to repairing discs.

Not all disc repair machines use the same process to remove the scratches in a disc. Manufacturers have gone to great lengths to design and refine the processes required to simply polish a plastic disc.

Below is an insight into the technical challenges faced by machine manufacturers and the solutions that are used for repairing your discs.

 


Liquid abrasive polish

b2ap3_thumbnail_abrasive-polish-process_20130701-101151_1
This is a very popular method for repairing optical discs. It is derived from the process used for polishing glass or plastic lenses. The concept is to have a thin liquid compound containing a grinding agent (fine abrasive substance) to gently remove the surface and make it smoother. The more abrasive the compound, the faster the material will be ground away. The finer the compound, the better the finish will be.

The difficult part is to get a solution that is just the right balance between the quality of the finish and the speed at which the material is removed. The faster the compound cuts through the disc the quicker the scratch is removed. But, if you make your compound too aggressive with larger grinding particles, then these particles will quickly settle to the bottom of the solution instead of staying in suspension long enough to repair discs.

b2ap3_thumbnail_scratch-pad-polish-featuresMachines that use this method usually circulate the same polish around to be used over and over until the grinding particles are no longer sharp and become ineffective. This liquid would be used in conjunction with soft foam or felt like pads that rub the polish around the disc. It is the polish flowing under them that repairs the discs so the pressure must be just right on the pad.

With this method the disc is repaired at a constant rate, so for every minute of repair the same amount of polycarbonate is removed from the disc. This is a very small amount that can only be measured in microns. (1 micron is 1 thousandth of a millimetre) the thickness of A human hair is up to 120 microns, the amount of plastic removed each minute inside this type of disc repair machine is from 0.3 to 1.8 microns.

The downside of this process is that the liquid can be messy and will dry to leave the solid element as a crust on any surface it is left on. So the Discs and the machine will need washing or cleaning after repairs. Secondly, with this type of machine the liquid polish will need to be agitated or shaken up to keep the particles in suspension. Finally, although this process will remove even very deep scratches in the end, it will take a long time and may not be cost effective.


Abrasive pads

b2ap3_thumbnail_abrasive-pad-processThis concept is the same as using wet sandpapers to remove the scratches from your cars paintwork before polishing with a cream polish. Using very fine sandpaper and water you can gently remove some of the paint to remove the scratch before moving to even finer paper to remove the scratches from the previous sandpaper until the finish is simply dull and no individual scratches can be seen.

Once this has been achieved then a car polish (that is lightly abrasive itself) will shine up the surface so that a glossy finish is restored.

This concept is excellent for repairing discs although a high degree of automation or manual intervention is required to swap from one stage to the next. With this process you can quickly remove as much of the disc as you need to repair the scratch with a sufficiently coarse sandpaper before moving to lighter papers to remove the scratches left by the previous paper.

b2ap3_thumbnail_scratch-abrasive-padIt is essential to have water running to rinse away the plastic debris being removed from the disc as this would quickly clog the sandpaper. After sanding there is a final stage where the disc is buffed with a cream polish to restore the glossy finish required.

This is the only viable method for cost effectively repairing very deep scratches or gouges into the disc surface. (This includes X-Box laser burn) The rate at which plastic is removed using the most abrasive stage in this type of disc repair machine is 9 microns per minute. This is far greater than the other methods and up to 20 times faster than other processes at removing the worst kind of damage.


Dry buffing

b2ap3_thumbnail_buffing-process-layout1This concept is simple, effectively just rubbing with a soft dry cloth. In practice the removal of a scratch is quite difficult to achieve. As we know if you rub a surface with a soft fabric it will shine up. (Like and camera lens or a window) This is also true of any optical disc. However, to take this one stage further, if the surface is rubbed with a cloth / fabric pad with sufficient speed and pressure then the friction will produce heat. This will cause the plastic to soften, allowing it to be reformed and flattened. The result is that light scratches will be filled in with the softened plastic from the surrounding area.

This process is difficult to achieve as the material used in the buffing pad, the speed of the pad movement, the pressure of the pad on the disc and the time any part of the disc is buffed for, is critical. If you get any of these wrong then the disc will either not be repaired at all, or completely melted beyond repair. When perfected, this process offers fast and inexpensive repairs that are completely dry. There is no mess and the disc will be ready to put back into the case after the repair.

The downside to this method is that it is limited to removing only the lightest scratches.


Hybrid systems

b2ap3_thumbnail_scratch-hybrid_20130701-102534_1These are the newest systems available…

This method is a mixture between the dry buffing and liquid polish methods. The concept being that soft pads are rubbed against the disc creating friction to heat up the disc and soften the plastic, as well as an abrasive polish being applied to the disc to cut into the already softened plastic.

As heat is essential the abrasive polish can’t be a thin running liquid as this would cool the disc back down. So a very small amount of thick cream polish is applied to grind the disc.

This is very effective, far less messy than the liquid polish approach and with the benefit of repairing deeper scratches than dry buffing method. Like the liquid polish method, on deep scratches this process will take a long time and may not be cost effective.


Choosing the right system for you

b2ap3_thumbnail_scratch-confusedIf you already own a disc repair machine and have ever encountered a situation where you could not repair a disc in a suitable amount of time, or you find the process to be noisy or dirty – then you might consider a change of machine, or an additional machine.

You may be able to upgrade to a new machine and repair all discs that come your way, or you may go for a 2 machine combination which could speed your day up and save you money in the long run.

You can contact us should you wish to talk further about machines:

Tel: 01202 489 500

sales@totaldiscrepair.co.uk

Written by Anthony Golden