On 08/30/2017 06:57 PM, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M


Stack them in a vise and mill.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M

In article ,
Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

https://www.bobvila.com/articles/how.../#.WadJJnWGNo8

"For thicker sheets of plexiglass, cut with a power saw€”be it a
circular saw, saber saw, or table saw. (To cut anything but a straight
line, opt for a jigsaw.) No matter which type of saw you choose for
the task, its critically important to use the right blade. There are
special blades designed expressly for acrylic, but any metal-cutting
blade with carbide tips can do the trick. Before committing to one
blade or another, double-check that its teeth are evenly spaced, with
no rake, and of uniform height and shape."

For the size you're talking about, I'd think that a table-type
sabresaw or jigsaw (with a fence) would be what you'd want.

For a fancier approach - the MightyOhm geiger counter kit can be
purchased with a two-piece acrylic case, the upper sheet of which has
some custom cut-outs made for the tube and the batteries. Their web
page says that it's "laser cut". Maker shops may have suitable
laser-cutters for their members to use, and there are service
companies which will laser-cut-to-size in your choise of acrylic
types.

In article ,
says...

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

[snip]

Is there a makerspace near you with a laser cutter,
or a laser cutting company?

Water jet cutting?

Dave Platt wrote:
In article ,
Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic
Plexiglas (Perspex) for LED displays?

I've thought about using a table saw with a cabinet-grade finishing
blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

https://www.bobvila.com/articles/how.../#.WadJJnWGNo8

"For thicker sheets of plexiglass, cut with a power saw€”be it a
circular saw, saber saw, or table saw. (To cut anything but a straight
line, opt for a jigsaw.) No matter which type of saw you choose for
the task, its critically important to use the right blade. There
are special blades designed expressly for acrylic, but any
metal-cutting blade with carbide tips can do the trick. Before
committing to one blade or another, double-check that its teeth are
evenly spaced, with no rake, and of uniform height and shape."

For the size you're talking about, I'd think that a table-type
sabresaw or jigsaw (with a fence) would be what you'd want.

For a fancier approach - the MightyOhm geiger counter kit can be
purchased with a two-piece acrylic case, the upper sheet of which has
some custom cut-outs made for the tube and the batteries. Their web
page says that it's "laser cut". Maker shops may have suitable
laser-cutters for their members to use, and there are service
companies which will laser-cut-to-size in your choise of acrylic
types.

I've contacted four Ebay sellers of Plexiglas panels, asking if they can cut
to my dimensions. Although they all advertise that they can cut to custom
sizes, all but one of them say that they can't cut that small due to
"liability insurance restrictions", whatever that might be. The other
quoted an unbelievably high price for a small order of 25 pieces. That's
why I'm looking to do it myself.

I looked at the Geiger Counter kit and didn't see any reference to any
plexiglas except for a clear panel covering the front of the unit, clearly
not what I'm after. At any rate, I'm not going to buy several $100 Geiger
Counter kits for which I have no use just to get $15 worth of plastic.

Yes, the finishing blade that I mentioned is a zero-rake blade, so that't
not a problem. Just concerned about my fingers when they get close to the
blade spinning at 3200 RPM.
I'm leaning toward building a hot wire cutter into a frame that will keep
the wire taut enough to make a straight cut through the plastic. Maybe
mount it alongside the fence on my tablesaw. That should keep everything
nice & straight.

Thanks,
Dave M

Randy Day wrote:
In article ,
says...

Anyone have experience in accurately cutting 1/8" thick acrylic
Plexiglas (Perspex) for LED displays?

[snip]

Is there a makerspace near you with a laser cutter,
or a laser cutting company?

Water jet cutting?

Don't know about a makerspace. Never heard of them. Have to see what
Google churns up.

Dave M

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

That should be no problem on a table saw. Make sure to use a zero
clearance insert. Cut into the short-side sized strips with a fence
than chop those up with a miter gauge with a stop. Perfectly safe.

Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Your first thought should work just fine as long as you take
reasonable care.

On Thursday, 31 August 2017 00:55:19 UTC+1, Dave M wrote:
Dave Platt wrote:
In article ,
Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic
Plexiglas (Perspex) for LED displays?

yes but not for LED displays.

I've thought about using a table saw with a cabinet-grade finishing
blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

https://www.bobvila.com/articles/how.../#.WadJJnWGNo8

"For thicker sheets of plexiglass, cut with a power saw€”be it a
circular saw, saber saw, or table saw. (To cut anything but a straight
line, opt for a jigsaw.) No matter which type of saw you choose for
the task, its critically important to use the right blade. There
are special blades designed expressly for acrylic, but any
metal-cutting blade with carbide tips can do the trick. Before
committing to one blade or another, double-check that its teeth are
evenly spaced, with no rake, and of uniform height and shape."

For the size you're talking about, I'd think that a table-type
sabresaw or jigsaw (with a fence) would be what you'd want.

I would rule out any type of saw for a few reasons
1. Such a small piece is impossible to hold effectively unless you're using a low speed handsaw, which is very ill suited to acrylic
2. Power saw speed plus very slow feed are required, and there's no way you'll get good enough control with such a fiddly unsupported piece
3. Anything else will crack it
4. Your fingers will be at too much risk


For a fancier approach - the MightyOhm geiger counter kit can be
purchased with a two-piece acrylic case, the upper sheet of which has
some custom cut-outs made for the tube and the batteries. Their web
page says that it's "laser cut". Maker shops may have suitable
laser-cutters for their members to use, and there are service
companies which will laser-cut-to-size in your choise of acrylic
types.

I've contacted four Ebay sellers of Plexiglas panels, asking if they can cut
to my dimensions. Although they all advertise that they can cut to custom
sizes, all but one of them say that they can't cut that small due to
"liability insurance restrictions", whatever that might be. The other
quoted an unbelievably high price for a small order of 25 pieces. That's
why I'm looking to do it myself.

It's doable, but the options shrink heavily.

I looked at the Geiger Counter kit and didn't see any reference to any
plexiglas except for a clear panel covering the front of the unit, clearly
not what I'm after. At any rate, I'm not going to buy several $100 Geiger
Counter kits for which I have no use just to get $15 worth of plastic.

Yes, the finishing blade that I mentioned is a zero-rake blade, so that't
not a problem. Just concerned about my fingers when they get close to the
blade spinning at 3200 RPM.
I'm leaning toward building a hot wire cutter into a frame that will keep
the wire taut enough to make a straight cut through the plastic. Maybe
mount it alongside the fence on my tablesaw. That should keep everything
nice & straight.

Thanks,
Dave M

Hot wire would do it, and gravity tends to keep it cutting straight. You can sand the edges afterwards to get dimension precise. An easier option is to use an abrasive stone in a dremel, cutting/melting as close as you can to your scribed line, but never over it, then sand it.


NT

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?


Polycarb is a bit easier to cut. Acrylic melts and gums up blades
easier.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M


I have scored and snapped Plexiglas. You would need to mount it
firmly so that the corners don't break. A small fixture (plywood) to
sandwich the piece should work fine.

Cheers

I've had a lot of trouble cutting acrylic on a table saw, or drilling.
The problem has been chipping on the back side. I haven't tried backing
it with a piece of wood - that should help.

What does work very well for giving a nice edge is a router. Not very
convenient for cutting into pieces, but nice for cutting shapes to a
template, or for finishing edges that have been cut with too much chipping.

On Wednesday, August 30, 2017 at 6:57:16 PM UTC-4, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M

at my job, we cut plexiglass( USA) on a sheet metal shear. makes a nice cut that requires little sanding to make smooth. 1/8 is thin. any tin shop would have shear that could cut that, even a manual one would work.

"Dave M" wrote in message
...
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas (Perspex) for LED
displays?

I need to make filters for some panel meters of my own design, but am having trouble finding
off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available on the web, I already
know about them. My meters are for a unique application and the available digital panel meters
can't be modified to fill my needs. The display is the really unique part, and I need to make my
own filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5" and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade. That's possible, but
somewhat dangerous due to the small size of the filters.
Also thought about hot wire cutting. That's quite possible, relatively safe (just have to keep
fingers off the hot wire). Might be hard to keep the wire taut enough to make straight cuts, and
guiding the plastic through the wire or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a bit dangerous due to the
small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M
Make and use a small parts sled to hold the pieces and keep your fingers out of
harms way. Do a search for "woodworking small parts sled" for an assortment
of photos and plans. Use the tablesaw to just score the plastic. Don't cut all the
way through. Snap on the score lines and file off any rough edges. A propane torch
will polish the edges to a glass like finish. Practice on a scrap first as it's easy to
burn the edge.
Art

On Wed, 30 Aug 2017 17:57:06 -0500, Dave M wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M

Variable speed dremel with a cutoff wheel will work.



--
Chisolm
Republic of Texas

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M


When a hardware store cuts plexiglass for a storm door or window, they
put the sheet in a glass cutting frame. That is nothing more than a rack
with a straight edge and a lever to apply pressure against the part you
want cut. Then they use a special cutter made for plexiglass, which is
really just a sharp blade. They score it with that cutter from top to
bottom. Then they use that lever to apply pressure and SNAP, they make a
nice clean cut.

I was in a place where I had to cut some myself. I did not have that
special cutter or a rack. I marked it with a sharpie. Then I took a
straight piece of aluminum, laid it on my mark, and scored it with a
utility knife with a new blade. Once it was scored, I placed the scored
line along the edge of a board and applied pressure with my hand. That
worked fine.

One thing I learned, never try to drill plexiglass. You will end up with
small cracks around the hole. I once wanted to put some hinges onto
plexiglass and learned the hard way about the cracks. Then I used a
soldering iron and melted holes. It was kind of messy, sicne the melted
plastic builds up around the hole and needs to be quickly removed while
it's still hot and soft, but that did work in the end. (The soldering
iron tip was pretty much trash though, I ssaved it for future plexiglass
holes, but would never try to solder with it).

On 30/08/2017 23:57, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M



I would use , don't know what they're called, miniture tenon saw from a
craft shop for marketry I believe, blade only about 1 x 2 inches, but
large handle, and teeth about the same as a hack-saw size and spacing

On 30/08/17 23:57, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Have a look at laser cutting. Bonus: you can cut complex
shapes as easily as simple shapes. Caution: not all
materials can be cut like that.

Look for a local Hackspace or Makerspace, if you want to
learn how to use laser cutters yourself.

Alternatively there are many commercial companies available.
Usually you just send them the CAD file and they return the
items by post, but obviously you could pick them up from a
local company.

On Wed, 30 Aug 2017 17:57:06 -0500, Dave M wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic
Plexiglas (Perspex) for LED displays?


Does it have to be perspex? 1/8" polycarbonate (Lexan) cuts with tinsnips,
no cracks, nice enough edge if you are covering it with any frame;
otherwise pass them a few times over a big file held in the vise.

Stuff that thin can be scored with a matt knife and broken on the score. With care, even on a curved score. For curved shapes, make a template in thick cardboard and cut along that. If you need to do this more than once, soak the curved edge in a very thin cyanoacrylate glue, then file it to the final shape. That will resist scoring by the blade.

Today, I have a Dremel Scroll-saw with a fine plastic-blade. Makes life easy. I tend to cut a bit proud of the final shape and use a very fine sanding disc to finish. It gives a nice edge and no flash.

Peter Wieck
Melrose Park, PA

On 2017-08-30, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

use a drop saw instead.

--
This email has not been checked by half-arsed antivirus software

On 2017-08-30, Dave M wrote:

I've contacted four Ebay sellers of Plexiglas panels, asking if they can cut
to my dimensions. Although they all advertise that they can cut to custom
sizes, all but one of them say that they can't cut that small due to
"liability insurance restrictions", whatever that might be. The other
quoted an unbelievably high price for a small order of 25 pieces. That's
why I'm looking to do it myself.


https://www.ponoko.com/laser-cutting/acrylic

send these guys 1:1 scale SVG with your outlines, they'll cut them into
a sheet.

they seem to have a "first order free" deal going at the moment.

--
This email has not been checked by half-arsed antivirus software

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Any suggestions as to a good, safe approach to cutting the plastic?

Repeatedly score it with a suitable blade and snap it along a hard
strait edge. When I was using a lot of perspex I had a strait edge
made with a steel rule glued to a wooden board. Occasionally I needed
to use two boards clamped in a vice.

Steve

--
http://www.npsnn.com

On 31/08/2017 08:57, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M



As others have said, use a CO2 laser. About 40 watts or higher should do
the job. They cost from about $4000 upwards, and are so useful that many
hobbyists and clubs have them. It leaves a nice smooth edge on acrylic.
Acrylic is one of the materials that it can cut well and safely. (e.g.
Don't ask them to cut PVC, it makes acidic fumes that attack the
mechanism of the machine and poison the bystanders.)

On 8/30/2017 5:57 PM, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

A triple chip for plastic would be your best bet.

On Aug 31, 2017, wrote
(in ):


One thing I learned, never try to drill plexiglass. You will end up with
small cracks around the hole. I once wanted to put some hinges onto
plexiglass and learned the hard way about the cracks. Then I used a
soldering iron and melted holes. It was kind of messy, sicne the melted
plastic builds up around the hole and needs to be quickly removed while
it's still hot and soft, but that did work in the end. (The soldering
iron tip was pretty much trash though, I ssaved it for future plexiglass
holes, but would never try to solder with it).

When drilling plastics like plexiglass, one does it flooded with tap water,
to prevent overheating amd melting into a gooey mess. Do not use oil - this
will crack most plastics.

Joe Gwinn

On Wed, 30 Aug 2017 17:57:06 -0500, "Dave M"
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

Use the score-and-snap method. Purchase a scoring tool from any of
the big box stores or many hardware stores. This tool has a backward
pointing scoring point and cuts a 90 deg Vee.

Score the plastic along a straightedge to about 1/3 the thickness.
That's about 3 passes with the scoring tool.

Position the plastic on a counter or bench with a sharp edge, locate
the score over the edge. Place your palm on the plastic and firmly
push down. The acrylic will cleanly snap. If you get a ragged break
or a chunk of plastic remains on one end, you didn't score deeply
enough.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

Jasen Betts wrote:
On 2017-08-30, Dave M wrote:

I've contacted four Ebay sellers of Plexiglas panels, asking if they
can cut to my dimensions. Although they all advertise that they can
cut to custom sizes, all but one of them say that they can't cut
that small due to "liability insurance restrictions", whatever that
might be. The other quoted an unbelievably high price for a small
order of 25 pieces. That's why I'm looking to do it myself.


https://www.ponoko.com/laser-cutting/acrylic

send these guys 1:1 scale SVG with your outlines, they'll cut them
into a sheet.

they seem to have a "first order free" deal going at the moment.


This looks promising. I'll look into it and see what the costs are (future
projects). It's a great concept, sorta like sending Gerber files to a PCB
house, and they make the board to my specs.

OK, thanks for all the suggestions. I just got a response from an Ebay
seller, saying that if I buy a suitable panel of his Plexiglas, he will cut
into pieces of my specifications at no charge!! Can't beat a deal like
that.
BTW, the seller's Ebay name is seefinestore, based in New York. Don't know
if he gave me a one-time deal, or if he will do this for any order, but it
solves my immediate problem.

Thanks for the pointer to ponoko, I'll keep it for reference for future
projects.
Dave M

Dave M wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

Real Plexiglas normally cannot be sheared. it can be scored with a special
knife and snapped off like glass cutting. It can also be machined with a
router or mill. Just be sure the cutter is super sharp and keep the tool
moving fast. Cutting slowly leads to heat build up and melting.
I need to make filters for some panel meters of my own design, but am
having trouble finding off-the-shelf bezels and filters of the sizes I
need. Before everyone tells me that there are cheap Chinese panel meters
available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to
fill
my needs. The display is the really unique part, and I need to make my
own filters for the displays. I need 3 different sizes; 1.25" x 2.5".
2.75" x 5" and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively
safe (just have to keep fingers off the hot wire).
I do NOT think you can hot wire-cut acrylic. It will make a LOT of fumes
and cut very slow. Acrylic has a pretty high melting point.

Might be hard to keep
the wire taut enough to make straight cuts, and guiding the plastic
through the wire or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be
tricky.
Just rectangles? Why would clamping be tricky? If making a lot, you clamp
a sheet by the edges, and rout out the pieces, leaving a little space
between parts.

My scheme, if really setting up to make a bunch, would be to set up a fence
on the table saw and cut a bunch of strips the length of the Plexi sheets to
match one of your dimensions. Then, stacking a bunch of these strips, cut
the other dimension. That would make a lot of parts quickly.

If you need highly accurate dimensions, then the mill is the way to go.

Jon

Once upon a time on usenet Bob Engelhardt wrote:
I've had a lot of trouble cutting acrylic on a table saw, or drilling.
The problem has been chipping on the back side. I haven't tried
backing it with a piece of wood - that should help.

What does work very well for giving a nice edge is a router. Not very
convenient for cutting into pieces, but nice for cutting shapes to a
template, or for finishing edges that have been cut with too much
chipping.

I worked in a high-end cabinet making workshop and have used a free-hand
spindle moulder before for cutting acrylic for kitchen drawer fronts etc.
Just fix it to a (thick wooden) template (for the bearing to run on) with
double sided tape and Bob's your uncle.

A small spindle moulder can be made using a decent router.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

Hi Dave:
Laser machining is the precision way to go.

If you require a steady supply I might be able to help out as I am making some custom plexi bezels and lexan implosion shields for vintage O'scopes and automobile dashboard fascia (flexible 0.35mm & 0.50mm thick material) right now.

I have 1mm, 3mm & 6mm clear plexi on hand as well as 0.35mm and 0.50mm EVA material.

If you need custom color 'gel' film filters bonded to the EVA I have a process developed for that as well.

Ancel


On Wednesday, August 30, 2017 at 6:57:16 PM UTC-4, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M

On 31 Aug 2017 11:13:25 GMT, the renowned Jasen Betts
wrote:

On 2017-08-30, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.

use a drop saw instead.

You can cut 3mm acrylic with a fine (eg. 80 tooth on a 10") carbide
blade on a table saw. No problem- just don't push it through too fat.

Or use a CO2 laser in the 40W range with air assist.

Or use a small CNC engraver with 4-flute mill.

--sp

--
Best regards,
Spehro Pefhany

On 8/30/2017 3:57 PM, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to fill
my needs. The display is the really unique part, and I need to make my own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75" x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively safe
(just have to keep fingers off the hot wire). Might be hard to keep the wire
taut enough to make straight cuts, and guiding the plastic through the wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again, a
bit dangerous due to the small size of the work. Clamping would be tricky.

Any suggestions as to a good, safe approach to cutting the plastic?


I have had good results on wood and countertop material with my HF
oscillating Multi-Tool. The flat round "sawtooth" blade cuts very
cleanly, with no chips. You can clamp a 3/4" board to the material being
cut as a guide. Then just press the blade flat against the wood, and
slowly move it through the material. It is slow, but very controllable,
and low risk. It would very likely work just as well on plexiglass.

On 31/08/2017 00:55, Dave M wrote:

snip

I'm leaning toward building a hot wire cutter into a frame that will keep
the wire taut enough to make a straight cut through the plastic. Maybe
mount it alongside the fence on my tablesaw. That should keep everything
nice & straight.

A hot wire cutter will create a lip on the cut surface.

I guess it could then be sanded off?

I think the sawing approach is easier, but mind your fingers.

The last time I cut a more substantial piece of acrylic I used a mitre
type of saw.

--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

On Wednesday, August 30, 2017 at 3:57:16 PM UTC-7, Dave M wrote:
Anyone have experience in accurately cutting 1/8" thick acrylic Plexiglas
(Perspex) for LED displays?

....

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M
All of these suggestions were interesting, but when I wanted something similar, my local plastics stores were willing to cut them to my requirements. This worked both in White Plains NY and San Jose CA. I tried your dimensions on the TAP Plastics web site, and it was $10 for one, $14.90 for ten, and $149 for a hundred (ISTR that the onesies price was lower for walk-in service, especially if you could find suitable stock in the scrap bin so you would only be charged the cutting fee). I vaguely recall that they used a band saw, but it has been more than thirty years.

On Tue, 05 Sep 2017 13:27:30 +1000, David Eather wrote:

On Thu, 31 Aug 2017 08:57:06 +1000, Dave M
wrote:

Anyone have experience in accurately cutting 1/8" thick acrylic
Plexiglas
(Perspex) for LED displays?

I need to make filters for some panel meters of my own design, but am
having
trouble finding off-the-shelf bezels and filters of the sizes I need.
Before everyone tells me that there are cheap Chinese panel meters
available
on the web, I already know about them. My meters are for a unique
application and the available digital panel meters can't be modified to
fill
my needs. The display is the really unique part, and I need to make my
own
filters for the displays. I need 3 different sizes; 1.25" x 2.5". 2.75"
x 5"
and 4" x 5".

I've thought about using a table saw with a cabinet-grade finishing
blade.
That's possible, but somewhat dangerous due to the small size of the
filters.
Also thought about hot wire cutting. That's quite possible, relatively
safe
(just have to keep fingers off the hot wire). Might be hard to keep the
wire
taut enough to make straight cuts, and guiding the plastic through the
wire
or the wire through the plastic.
Also thought about cutting on a drill press or milling machine. Again,
a
bit dangerous due to the small size of the work. Clamping would be
tricky.

Any suggestions as to a good, safe approach to cutting the plastic?

Dave M




This is a real non-issue. Just look up laser cutting services on Google
and you find a heap that do one offs at low cost




--
The latest set of Shadow Broker tools shows the UK, USA, Canada,
Australian and New Zealand spy agencies were hacking into domestic home
routers. Who gave them permission to spy on our kids?