Tried cutting on Polycarbonate, broke my needle..

[David34]

Hey guys I ran an experiment because everyone on here seems to think that Souris blanks are Polycarbonate.

So I went and got some local plastic company to cut me some tester blanks of Polycarbonate. (clear 2mm 12")

I setup the cutter and cut a sample, only to find one side of my needle was damaged by it. Brand new needle.

the blanks Souri sells cannot be PC. Unless there is different grades of PC and Im not using the right one?

He states on his web page that the blanks are PVC, but so many people say they are PC, Im really confused.

Id like to buy my emergency blanks (when I run out) locally rather than from Germany from time to time.

Can anyone please confirm for me ?

[Jccc]

Did you use a diamond to cut polycarbonate or a sapphire? I remember i tried cutting with a sapphire on Pc and it sounded bad. I know if you set it up correctly for impressing then it should work out. As thats what alot of people seem to be doing.

A diamond shank should be able to cut poly i believe.

[opcode66]

You can't cut poly with a sapphire. You can emboss/impress with sapphire. But, no cutting. It will break your stylus.

You absolutely need to use diamond to cut poly or pvc.

[tragwag]

if you're looking to buy polycarbonate blanks in the US, send me an email: tragwag (at) gmail (dot) com
I will echo everyone's thoughts here, in that diamond is the only way to properly 'cut' polycarbonate.
if you are using sapphire, you must using the 'embossing' or 'impressing' method.
there is plenty of info on the forum regarding this distinction, try the SEARCH function.
sorry to hear you broke a stylus, that's never fun.

[David34]

Thanks for all your replies guys really appreciate it !

But I am using a souri diamond ?? I checked the diamond after cutting the PC, and one side has dents out of it ??

So shall I get PVC or Polycarb blanks ? Are there different grades to look out for ? I dont want to damage another needle in the pursuit of cheap blanks !

Im looking into getting them from China!

[powerstrip]

Thanks for all your replies guys really appreciate it !

But I am using a souri diamond ?? I checked the diamond after cutting the PC, and one side has dents out of it ??

So shall I get PVC or Polycarb blanks ? Are there different grades to look out for ? I dont want to damage another needle in the pursuit of cheap blanks !

Im looking into getting them from China!

please don't buy anything from china.

[tragwag]

what you're looking for is polycarbonate.
there are plenty of threads that mention what to get, and where.
I can sell you already cut out blanks, send me an email - tragwag (at) gmail (d0t) com

maybe you have a bum stylus?
hows the heat on that system?
You should give a search for Opcodes (todds) plastic cutting guide

[opcode66]

And, here it is!

The video is in the final stages of production. I've seen a couple edits now. It is very close to being done!

[David34]

Thanks guys.. Im cutting with a diamond I dont understand how Chinese POLYCARB is any diff from the expensive stuff in Germany

[David34]

I really just dont understand why its such a secret what Im cutting here .. Souri claims its PVC, Most claim its Poly carb..

Ive tried Polycarb, broke my diamond. The only thing left is PVC.. ? Which only has protective film on one side?

Why cant anyone give me a straight answer here ? I HAVE searched the whole thread in details and that is WHY I'm so confused.

Its not the price of the Blanks its the postage that is killing me !

Come on guys.. Please please !

[Lima Victor]

Cut/shave off some material from your blanks, or save the swarf if you have any. Source some PVC (like a normal vinyl record or PVC piping). Set it on fire and compare the smell.
Polycarbonate and PVC smell a bit different when burning. This way, you'll at least know if the blanks are PVC or not.
Acrylic (PMMA, Plexiglas) has a terrible garlic-onion like smell.

Be careful. Don't set anything (else) on fire, and burn just enough to smell the stuff. It is not healthy to breathe in the smoke, of course.

[tragwag]

PVC is the material used to press records.
If you are buying PVC blanks in circles already, it is important to note that they will have the contour of a pressed record.
(there is an RIAA standard for that in the disc recording anthology)

Polycarbonate is more like "plexiglass" though it is not that.
Polycarb comes with sheeting on both sides, is normally clear, and always flat all the way through.


Many people on this forum cut with a diamond on polycarbonate.
I do not know of anyone who routinely cuts with a diamond on PVC, though it can be done.
hope that helps.

[David34]

Thanks for your replies. The swarf that came out when I broke my needle wasn't like the stuff that comes out when I cut the Souri blanks (Souris looks like really thin hair, the Polycarb was all rough looking)

[David34]

From Souri web site..

[opcode66]

I can easily dispel one myth. If series blanks were pressed as people are trying to say, then how is it that they look black but cut clear? That is not possible. You can't press multiple layer discs from pellets of plastic. How coupd you press a black core with clear coating. Not possible.

If it is pvc, it is manufactured in layers. And you only cutting into the glossy coating.

I will buy some sheets of pvc and do some testing.

[rsimms3]

You can but it would be labor intensive, it's how picture discs are made. Black puck for the core and then clear film on the outside minus the paper "picture disc".

http://youtu.be/1hKgYLxZANU?t=1m21s

[opcode66]

Your comparison is not quite accurate.

Picture discs are made by pressing only one type of plastic pellet (clear) over a printed disc in the middle. The disc is near paper thin. The result is a record with a printed disc in the middle. The printed disc doesn't usually come out completely to the edge of the final pressed disc. Instead it is usually a few mm smaller in diameter than the final disc. It can be noticeable.

The black plastic used to make blanks has a very thin layer of clear material on it. Maybe 8 mils thick on each side and completely uniform in thickness. I have never seen a sheet that has clear plastic covering the edges. And, the black plastic part represents probably 95% of the total material. On a picture disc, I think the clear plastic is more than half the total material. On all plastic blanks I've seen, including souris, the black part is visible on the edge. It is not covered by clear as it would be in the picture disc scenario.

Therefore, I don't think these are pressed by taking a large black disc and pressing clear over it. Anyway, what I was originally saying was that it wasn't possible to put a layer of clear pellets down, then a layer of black, they a layer of clear, press it and get a nicely clear coated black disc. I wasn't saying you couldn't press clear over a black core. But, back to that, wouldn't the core have to be a plastic with an extremely high melting point. Wouldn't you distort the black part by pressing clear around it (or even have the two mix together like a splatter disc) if it wasn't a very heat resilient material? I don't press, so I don't know this part...

It should be noted that all this discussion about pvc or poly is sort of chasing your tail. I hate to tell you all, but you aren't really cutting into either. You're cutting into the clear glossy layer. Which, I have no idea what it is composed of. I'm guessing clear poly but I don't actually know for sure. No one at my distributor can tell me either. Not even the US Importer for Bayer. I'm at the point where curiosity has got the best of me.

If someone is willing to send me a blank from Souri, I will have a lab analyze the materials. I will also do the same with Makrolon to find out exactly what the clear part is that we ARE actually cutting into. If you cut deep enough to hit the balck part of the disc, then you will almost certainly snap off the tip of your sylus. So, is it the depth, or the fact that the black part of the disc is actually a hell of lot harder material than the clear coating.

I think most all Trolls have been under a false impressing that they are cutting x material or y material when really they are cutting the f-ing clear coating on x or y material. So, what we should be focused on is what exactly is the clear material coating all these discs. Right?

Till next time. Opcode66. Over and out.

[aaron]

To muddy the waters further, I posed this question to bayer:

Is it true that Makrolon GP, black L10, actually has a thin clear layer on the surface of each side?

Reply: Makrolon GP is an monolithic extruded polycarbonate sheet that does not have a cap layer- The color is part of the extrusion process.

I then asked: I had just heard that the shiny finish is made by a very thin layer of clear plastic. Is that not the case then? How is the outside surface made shiny?

Reply: It is polished by rollers when it is extruded.

[opcode66]

If that is the case, then what I keep calling the coating is in fact clear poly and the black middle part is clear poly with some sort of black material added. So, clear poly is extruded with black doping in the middle and rolled into a sheet where there ends up being a clear skin once done. Make sense? All I can say is when you cut a black disc, the chip is clear. And, when you use a razor blade to shave a thin piece of the edge of a disc, you can see it is clear for a short length then black.

[mossboss]

Hi All
Picture discs are certainly made with any colour PVC core All the regrind which may also include bits of label paper in it Not deliberate but a mistake like someone ground a few records with the labels still on them
It is really a simple sandwiching process
It goes like this
Manual press
Bottom mould
Long Bottom center pin, This is imperative
Clear sheet of PVC, 8-15 m The center hole normally drilled on the square cut blank sheets One is placed there on the face of the mould
Than
Printed matter, Side A Face down,
Followed by
Lump of PVC from extruder, Puck, Cake, Any colour Some master batch or white PVC may be added in the hopper it softens up the whole mass
Than
Printed matter Face up
Followed by
Clear sheet of PVC
Top mould
Nothing
Close the gate press the go button whatever it needs
The press closes presses the Pic Disc as normal, a much longer cycle is required, they get quite heavy by than needing a long cooling time
The paper sticks to the inner puck PVC
The clear sheets overlap the printed matter so as to seal the stack of parts at the edges
No pellets are used on the process at all in the mould itself only in the extruder
The press is slowed down quite considerably else it will tear up the printed matter making rejects

Next
The mysterious material used by Souri whatever it is Is co Extruded
This is a process where two or more different materials can be combined
In this instance as an educated guess it most likely be,
A main extruder pushing the core material into a sheet mould mounted at its head with 2 smaller extruders injecting their material at either side of the sheet mould then passing the sandwich through a set of burnishing rollers
The alternative method is to extrude the core sheet on a single extruder
As it moves along the line after it has stabilised, two clear sheets blown as a tube than split at the pinch rollers so as to become two sheets are layered on either side of the main sheet
With its remaining heat in this sheet this thinner material would fuse on the faces of the core material
Often further heating is used along the heating tunnel so as to ensure good adhesion of the covering material to the core,
It is than given a polish with a set of rollers a protective film is added on either side
It is cut down to specific lengths packed ready to go out
I doubt that the material is cast as it is far to thin for a casting process to be used which is another method of manufacturing various plastic materials into sheet

Cheers