Record Masters & Stampers A short Treatise

[mossboss]

Vinyl Record Plating Shop

Here are the necessary steps so as to to make stampers as well as masters and mothers for any Vinyl record Pressing Plant
A little bit of back ground on the subject for new boys in the hood as well as the steps required so as to achieve the goal
This is not meant to be an exhaustive description of the process but a fairly good description of the equipment as well as the process which is generally used in plating shops attached to a plant or supplying matrices to the industry

Terminology

Since there are different definitions of the parts that result from any plating shop any where in the world I have used First Negative as the alternatives used elsewhere been a master a father I have used a positive as the second metal part as against Mother or son Finally a negative first or second I have called a stamper as against a mold or some other definition
Much to my chagrin I use the word plating due to its popular use today instead of the proper name which is of course electroforming

The process

So we now have a master with some tracks on it we wish to produce Vinyl records with the music from the submitted masters which have been mastered for Vinyl
So the cutting is done on a cutting lathe which we have sufficient information here so as to be able to skip the steps there
The cut lacquer is than sent to the plating shop so we can get metal work so as to get the presses running
Once the lacquers arrive at the plating shop the following steps are necessary

Inspection

The lacquers must be inspected for any visible damage that may have taken place during transport
Once they have been approved they are than get allocated a date for production

Pre-treatment

Assuming a clear on damage they are than passed for pre treatment in the washing and cleaning process which will remove any particles remaining at the groove as well as any lubricants or any castor oil which may have oozed out of them after they have been cut
Various recipes are used around the world with each facility favoring some soaps and cleaning materials over others with saponin as well as very soft squirrel or camel hair brushes used by just about all of them in the process
Copious amounts of water with the last and final rinse done with distilled water, is used during the various steps, the cleanliness of the lacquers is paramount for a good result The final result is a very very clean lacquer with out any blemishes on it which is easily checked by looking at them at an angle observing and seeing a contiguous film of water adhering to the face

Silvering

The cleaned wet lacquer is than placed on an angled rotating turntable in a specially made booth the lacquer is than sensitised with tin chloride so as to be able to take furher treatment This further treatment is a very thin one or two atomic layers of silver applied so as to render the lacquer conductive to electricity
This process is critical to quality of the final pressed record so it is carefully controlled so no more silver than necessary is applied on the surface it has to have a mirror like finish with no dull spots or any cloudiness visible as a dull or a goldy colour would certainly produce a crackly record
The process is carried out quickly with a 3 nozzle gun generally used the aim being that the liquid chemicals used do converge at the face of the lacquer all at the same time
Silver nitrate, out of one nozzle, reducer from the other and an activator such as glucose or other propriety products are generally used,from the third nozzle, are sprayed all at the same time
The chemicals do have to be made up with various steps taking place for each and every one of them they are made in a concentrated form for a weeks production A portion is taken out for the day's needs with all remaining discarded at the end of the week The reason is that it takes some time to prepare everything so a batch is made once in a sufficient quantity so as to last for the week or so
The final step on the silvering process is an extremely thorough rinse with distilled water while making sure the surface never dries up or oxidation of the silver would start immediately making the whole of the above redundant
If it is the case that for some reason the silvering process has gone bad the lacquer is stripped off and the process starts from the beginning with no harm done apart from loss of chemicals as well as time

Pre Plating

The wet lacquer is than placed in the preplating baths where a layer of pure nickel is plated on the face The reason for that is that since the silver coating is extremely thin it can only take a very small amount of current which may not be achievable on a standard plating out bath although baths have been produced where the current can be controlled to such low levels
A further reason for preplating is the fact that it has to be done at a low temperature so as to prevent distorting the soft lacquer coating so about 35 C is usually the maximum temperature set on the preplating baths
The current is set at around 3-5 amps at about 1 -1.5 volts and about 1-2 thou of nickel or a bit more is build up over half to one hour The lacquers are than able to be transferred on the growing out baths for the build up of the nickel to about 10 to 12 thou

Plating up

Growing a Negative/Master/Father/Matrix from a preplated lacquer

The terminology around the world is different for the very same thing therefore the names above
The preplated lacquers can be kept aside or placed immediately in the main baths so as to make the first metal part a negative of the lacquer, as a rule nickel sulfamate solution is used today as it has been for many years in the industry There are various types of construction of those baths
They generally follow a pattern well established from very early days where the lacquer is placed and fixed via a hand type threaded knob on a spindle with a motor driven insulated rotating shaft direct or vial belts or gears The motor is generally mounted on a hinged lid which when closed it allows the lacquer to be fully submerged in the green nickel sulfamate solution Generally there is a two section compartment above a return tank Each compartment is referred to as a cell
The lid when it is lowered is in close vicinity to titanium baskets which hold the de polarised nickel chips with a continuous supply of solution so as to maintain a level in the cell where the plating up takes place
The level is maintained by a standing pipe which allows excess liquid to drain into the tank bellow This liquid is continuously pumped through a bank of filters filtered down to 3-5 microns or rough deposits would result otherwise
About 400 litres or 100 gallons of liquid is maintained in the holding tank for a pair of cells and another tank of similar size is piped up to it where a dummy plating setup is installed as well as where the filter bank as well as the circulating pump is also installed so as to maintain the level of liquid in the plating cells as well as act as the primary pump of filtered solution to the system
The temperature of the solution is maintained at about 45-48 C as the preplated lacquers still have the underlying soft material further deformation is possible with higher temperatures
A rubber ring is placed around the lacquer so as to stop heavy metal build up around the edges which makes it hard to split open the parts
Lower current is used at around the 100-120 Amps stepped up gradually over 2 odd hours with around the 12-15 thou of metal built up the lower current prevents deformation of the lacquers due to temperature raise during the passing of current from the anodes that is the nickel chips to the cathode that been the lacquer on the spindle

Growing a Positive/Mother from a Master/Negative/Matrix

Again terminology around the world
The plated up first metal part is separated from the lacquer by carefully filling away the nickel build up around the perimeter of the lacquer than prying away the nickel layer which is a perfect mirror image of the cut on the lacquer as well as everything else that is inscribed on it like matrix number catalog number as well as any imperfections contained on the face of the lacquer
This nickel formed first negative will be placed back into the plating bath so as to grow a mirror image of it This second step will produce a positive image which will be exactly the same as the cut on the lacquer
The first thing that takes place after the metal is stripped of the lacquer is to remove any bits of lacquer that has detached sticking to the metal as well as a de silvering step so as to remove the silver that was on the lacquer
The positive from the negative will also have to be separated afterwords so the negative has to be treated with certain chemical so as to allow for this separation to take place
There are various treatments used for this purpose such as sodium hydroxide albumin fish glue as well as other methods of treatment
The whole idea is to allow a separation layer which would not make any difference to the music that has been transferred from the lacquer to the metal
The treated negative is than placed in the bath with a rubber ring around it so as to stop metal build up around the back as well as facilitate separation of the two parts
Plating takes place at around the 55-60 C as there is no issue of distortion or deformation
A high current is used at around the 150-200 Amps stepped up gradually over 2 odd hours with around the 12-15 thou of metal built up
Once again the two sides are separated by cutting or filling around the perimeter edge than carefully prying the to sides apart, the end result been a positive side has been produced from the negative which is a perfect replica of it and since it was derived from the cut lacquer a perfect replica of the original

Growing a Stamper/ From a Mother/Negative/Matrix

Explanation of 1 step 2 step and 3 step plating

Ok here is where we need to clarify a few things so people are clear about some terminology which has crept in the game
Now days we have a single step a two step and a three step process which of course is dictated by cost rather than any other reason including quality

One Step Process

Every one that has read up so far it will be obvious that we can press records from a negative metal plate so as to get the tracks on to vinyl
we have that already on the very first step of the plating process
This is than the one step process where the very first metal plated is turned into a stamper placed on the press It is the lowest cost as the second and third step is not carried out It has its advantages as well as disadvantages
Firstly a lacquer which has produced a metal plate is unlikely to be used again for simple reasons The groove is often damaged by the removal process of the plated part which renders re use of the lacquer a bad choice as the sound will not be a true representation of what has been cut So it is a once only exercise
This first metal plate can be and it is of course used so as to press records but no future reference or the ability to produce a second stamper exists once it is turned into a pressing plate
So if the sound is unacceptable to the client clicks or pops are present or any background hiss or noise exists another lacquer has to be cut at whatever cost and the process repeated this is a disadvantage
Of course there is an advantage that is the fact that it is only once removed from the original music submitted for cutting and given that it is a successful cut as well as clean that is the closest one could get to the original
Keeping in mind the cutter has no clue how good the cut was how clean or if it has background noise as well as any horns or for that matter how it would sound after been pressed So its a risky situation as it is more of a gamble rather than good practice

Two Step Process

Once again the reader so far would already know that we so far have described a two step process where we have a first negative and a first positive
Since the positive is an exact replica we can play the metal plate on a fairly large platter turntable with a 16" arm so as to establish how clean it is and if the negative which we have already in hand is good enough to go on press
Assuming that the positive plays clean and well without any jumps or clicks pops and background noise the green light is given for the first negative to go on press
This first negative is than processed further so as to make it suitable to be mounted on the press so as to produce vinyl records
The advantage here is that we have a metal positive where we can grow another stamper from, in actual fact it has been established over many years that up to ten stampers can be grown out of a positive before any degradation is audibly detectable
That would be again more of a stroke of luck rather than design
It has to be said that once again the cutter has no idea of the quality of his cut until after the event He can apply all the necessary skill as well as steps required, the fact remains that he has no control of the inconsistency underlying the lacquer manufacturing process its inconsistency from one to another as well as the state of his cutting stylus and no one plays a cut lacquer back as it will be destroyed by the play back stylus

Three Step Process

Here we are now back in traditional territory where the 3 step process was always the case before the today's cost cutting misguided idea which quality sacrifice is the end result, that has descended upon the industry
So having taken the process so far into the two steps we find that the positive plays badly with clicks pops as well as background noise
The positive is than de clicked and de popped by the use of a sharp instrument under microscope and is played back again
The process been repeated until all clicks and pops disappear the positive is clean from them but the source of any background noise has to be established
This noise may be from bad silvering a blunt or dirty cutting stylus or be inherent on the submitted masters supplied originally which the mastering guy or the cutter has overlooked
(Yes I can hear the protest's already but let the one who has not sinned cast the first stone OK!)
Assuming that is is from bad silvering and it is at the intro part of the cut a heavy rouge cutting compound will be applied to the affected area on a rotating turntable with light pressure applied on some cotton wool pad so as to remove the miniscule imperfections on the cut
A much lighter finer paste like Silvo will be also used over the whole surface of the plate so as to remove any other background noise existing elsewhere
The plate is than thoroughly cleaned with various methods washed in distilled water and played back again so as to establish its quality status if it plays clean than it is again treated with a separation layer placed back in the bath and another negative is taken of it this time with a 100% assurance that the resulting stamper will be perfect to go on the press
The plating takes place at around the 55-60 C at quite high current around the 120-250 Amps where a stamper will be grown to 12-15 thou in about an hour or so
There is no fear of distorting or deforming as it is a metal to metal step
Once again a rubber ring is placed around the perimeter

Preparing a stamper

Regardless of which step is used for the production of a stamper the following steps are necessary so the metal plate is able to be placed on to the press to produce records
The following description applies to all size records be them 7" 10" or 12"
So for us to have a 7" record pressed the lacquers cut have to be 10" in diameter for a 10" they are 12" and for a 12" record they are 14" in diameter
The excess area is necessary to allow for the following
1. To provide the cutter with a small area so as to perform a test cut to make certain that he's gear is all in order This test cut can be played back as it will never make it into the final record
It gives the opportunity to adjust parameters check the cut width the stylus as well as various settings that need to be there for a successful cut
2. To allow the extra material for the forming of the metal plate over the sides of the pressing molds so as to be securely mounted on the Record Press
We now have in our hands a negative plate which has been grown from a lacquer or a positive in a one two or three step process
It is a perfect image of the lacquer regardless of the steps taken It is rough at the edges from the prying opening step besides it contains a test cut and it is way bigger in diameter than required
The first step is to placed it in a metal circle cutter where the excess metal is cut out It is than placed in a rotating turntable face down where the back side is finished with emery cloth from 120 grit down to around 240 grit so as to have a very fine finish free from any rough spots
It than placed on a centering machine, the turntable on this machine is magnetic and it is floating so it can be moved a little around the center point
The stamper is held by this magnetic force flat in its place it is placed around the center point of the turntable Above this turntable there is a light as well as a magnifying lens which project the lock groove into a display The objective is focused in the lock groove and the whole turntable is moved while it is rotated so as to find the lock grove which is than lined up with marks on the screen
This is a crucial step as if not done correctly the records will spin off center Once the center is located a 1" hole is punched into the stamper
The stamper is than removed and it is place on a forming press which forms the center with an angled or a straight flange where the stamper will be held on to the pressing mold as well as where the center pin will be located which forms the hole on the record
At the same time the perimeter of the stamper is formed at an angle of around the 30 Degrees which goes over the mold to be again held down firmly but not to tight around the mold

Conclusion

So that's about the whole story on preparing metal parts for the purposes of pressing vinyl records the above has some missing bits such as the composition of the bath as well as a description of the various chemical used as well as some other finer points on the process
As stated earlier it is not a step by step description but a rather broad outline of the steps with the emphasis placed on the shortcomings of today's approach on short cutting due to cost which sacrifices quality

Some notes of interest

In essence in all record presses the stamper is held tightly in the center while just held firmly on the outside perimeter The reason for this is the fact that since there is a heating and cooling cycle every 30 odd seconds or so there is a tremendous expansion as well as a contraction of the mold for every heating up and cooling down of the record
Effectively the mold expands and contracts by about 30-40 thou on every cycle as the cooled down mold at around the 20 odd degrees C is heated up to about 145-150 C in about 6-7 seconds kept there for another 2-4 seconds and than cooled down to ambient or 20 odd C in another 10 odd seconds
If the stamper was to be held tightly around the perimeter it will break in about 3-4 cycles so it is held down firmly but allowed to move while some buckling also takes place while on heat
This is quite visible It works fine the buckling is of course of no effect on the pressing as it gets spread out with the pvc biscuit as it is pushed along from the center to the edges while the press is closing

Cheers

[opcode66]

Thank you Chris!!!! Excellent information.