Cutting on acrylic instead of polycarbonate...

[piaptk]

Just found out from tommie that you can cut acrylic (not polycarbonate) with a standard sapphire needle. Not sure how long your needle will last, but it cuts nice and sounds good.

[opcode66]

What is the lifespan like? Polycarbs give something on the order of 100,000 clear playbacks.

I would love to cut plastic without a diamond...

Is anyone supplying acrylic discs?

[piaptk]

I'm nit sure.... Only made a couple test cuts, and haven't played them back many times... I'd imagine it would be similar to polycarb... You can get acrylic at any plastic supplier... You should just raid their scrap bin...

[d]

Hi Piaptk,

Do you mean PMMA (polymetylmetacryl). Is this a material we are talking about? Just looked at our plastic suplier and haven't found the "acrylic sheets"...

Maybe Tommie can tell us about the material more? Maybe link to a current sheets he used?

Thanks a lot!

[aaron]

I've done some experiments with acrylic (plexiglass) and sapphire, and got some decent results... I could never get a totally silent groove though (didn't use stylus heat). I actually even got quotes from some companies that could supply black acrylic discs (slightly more expensive then PC).

I kind of abandoned it though, since I read that acrylic is actually harder than polycarbonate, and I didn't want to trash my sapphire... but thinking about it, if you could get enough acrylic cuts out of a sapphire to make it worth your while maybe that'd be ok

[cymbalism]

Unfortunately I've done lots of tests on many different colors of acrylic and clear is the only kind that works. Supposedly colors are cast so the pigmentation will not be as pure as the clear would be because they actually roll out the clear when making sheets.

The downfall is it is a lot more brittle than poly is. In fact just cutting scraps in my workshop and drilling centers out is nasty business because it chips and spiderwebs pretty bad with a standard drill and table saw. I'm going to give it a shot with a CNC machine and see how well it comes out and let people know here. I've done lots of tests and gotten very good results, same results as with laser discs, nice chip suction and groove depth. It will never be as quiet as acetate but a tiny bit of surface noise and being able to use ruby or sapphire is a hell of a lot better than shucking out $350 on a diamond to cut a handful of polycarbonate in my opinion.

[d]

Hey,

thanks for information.

I had to work a little on plastic drilling so I found nice drills that are very good on plastic, on them there was a mark that they are suitable for PVC. As I know there is special drills for CNC to cut plastic. Most of generel drills for plastic I used Irwin brand.

Have you tried saphiere or ruby to cut acrylic? How many hours have you got till now.

D

Unfortunately I've done lots of tests on many different colors of acrylic and clear is the only kind that works. Supposedly colors are cast so the pigmentation will not be as pure as the clear would be because they actually roll out the clear when making sheets.

The downfall is it is a lot more brittle than poly is. In fact just cutting scraps in my workshop and drilling centers out is nasty business because it chips and spiderwebs pretty bad with a standard drill and table saw. I'm going to give it a shot with a CNC machine and see how well it comes out and let people know here. I've done lots of tests and gotten very good results, same results as with laser discs, nice chip suction and groove depth. It will never be as quiet as acetate but a tiny bit of surface noise and being able to use ruby or sapphire is a hell of a lot better than shucking out $350 on a diamond to cut a handful of polycarbonate in my opinion.

[aaron]

d - Yes, sapphire/ruby into acrylic

I'm also curious, cymbalism, through your experiments did you use the same stylus? That's the only thing that scared me off is I just assumed I'd kill my stylus too quick.

Also, if clear is the only thing that works, could you make a sandwich of two clear pieces and somehow blacken the insides of them? Sorta like what souri does/did.

[cymbalism]

I didn't keep track of time per se but I used an old stylus which I used for lacquers for a good 30+ hours when I was cutting on the acrylic and it still cuts good with minimal surface noise.

I'm sure you could sanwhich whatever color you want between the two pieces of acrylic to make it colored but I still haven't tested the spray adhesive route yet, on my list of things to do though.

I'll have to rip a test I did to show you guys. Like I said, I would totally switch over but the fragility is what's scaring me off. One good drop of the record would probably kill it.

[d]

Nice, I say!

Take a rip, we are all waiting

What brand of acrylic is used?

[fraggle]

@Cymbalism

do you reckon acrylic sounds as good as poly?
I got some pvc and polystyrene samples as well.
As soon as i get my diamonds i will post the results.
cheers

[cymbalism]

@Cymbalism

do you reckon acrylic sounds as good as poly?
I got some pvc and polystyrene samples as well.
As soon as i get my diamonds i will post the results.
cheers

I would say yes plus you don't need to use a diamond for it!

[aaron]

Regarding the fragility of acrylic, I don't think I'm too worried about it... since it's round, you wouldn't have to worry about it hitting a corner or anything. Plus, how often do you drop records on a hard floor?

I will post a sample that I did a while back, I had some noise in my cut but it was definately not as bad as like a picnic plate cut or something.

[fraggle]

Where do you get the sapphires from then?

[aaron]

I'm using a long-shank Transco.. I think they're still available from Apollo Masters

[aaron]

Here's a sample I made, using a sapphire, mounted in a Presto 1-C, on my home brew lathe a couple months ago:

http://home.comcast.net/~bathory/test-acrylic.mp3

I tried to do some tests last night, but I (stupidly) did some experiments trying to cut polycarbonate a while back and couldn't get a good cut.... I guess I dulled the stylus. As the night went on it sounded worse and worse... looked at it under a microscope and the tip is broken


I got a quote from an acrylics manufacturer for making clear 12" extruded acrylic blanks (laser cut with a hole in the center)... would anyone be interested in obtaining any? Depending on how many I order, it will be in the neighborhood of $6-$7 a piece... I could give a more exact price depending on interest.

[mratx]

Has anyone tried cutting the next series of softer plastics than acrylic, like acetal? I'm assuming from comments in other threads that polypropylenes and polystyrenes are too soft, but acetal is supposed to have reasonable wear characteristics, plus is commonly available in black.


Mark

[aaron]

Is it really softer? Maybe I don't understand the "rockwell hardness" scale, but I saw a chart and it had a higher number than both PVC and polycarbonate. There's a place not too far from here that sells 12"x12" sheets of it real cheap... once I get a new stylus I'd be willing to try it.

[mratx]

There are different formulations, but supposedly in general it's not as hard as acrylic, although it's harder than PVC or nylon. I figured if acrylic can be cut with a sapphire, you should definitely be able to cut acetal, it's almost always referenced as easy to cut with sharp tools. But I have no idea how it would stand up to repeated plays.



Mark

[Jccc]

Wow! that acrylic cut sounds nice! There is this plastic place is San Diego: http://www.sdplastics.com/ that sells all types of plastics. Im gonna have to go there and pic up some Acrylic.

That place also sells Acetal. I which i will have to experiment with also.

Thanks for the ideas and experimenting