One issue with cutting templates (for my router, etc.) out of plastic
is the heat generated by the blade and the resulting melting (and,
then fusing) of the material behind the cut.

I had a paper pattern spay-glued to the sheet of salvaged 3/16"
plastic (from an old Staples Display Rack - great dumpster for
"finds") and I tried spraying a lubricant ahead of the cut line. The
paper pattern absorbed the oily/waxy spray and the cut material fell
away leaving a clean cut behind. I had switched to a blade with fewer
teeth (as I didn't have one of those plastic slicing blades on hand
and thought reducing the number of teeth might do the trick before I
thought of the oil spray).

THe stuff I used was foamy/waxy as opposed to the fine clear spray of
a WD-40, say. I cannot say if WD-40 would have worked as well and
cannot recall what the stuff I used was called. But The difference was
so impressive that I thought to post it here FYI.

Hoosierpopi wrote:
One issue with cutting templates (for my router, etc.) out of plastic
is the heat generated by the blade and the resulting melting (and,
then fusing) of the material behind the cut.

I had a paper pattern spay-glued to the sheet of salvaged 3/16"
plastic (from an old Staples Display Rack - great dumpster for
"finds") and I tried spraying a lubricant ahead of the cut line. The
paper pattern absorbed the oily/waxy spray and the cut material fell
away leaving a clean cut behind. I had switched to a blade with fewer
teeth (as I didn't have one of those plastic slicing blades on hand
and thought reducing the number of teeth might do the trick before I
thought of the oil spray).

THe stuff I used was foamy/waxy as opposed to the fine clear spray of
a WD-40, say. I cannot say if WD-40 would have worked as well and
cannot recall what the stuff I used was called. But The difference was
so impressive that I thought to post it here FYI.

That is a keeper. If only we could find some of that foamy/waxy stuff.
Now, where did I put that saber saw? I know I had one somewhere.

--
Gerald Ross

Anything is good and useful if it's
made of chocolate.

For scrollsaw work a layer of packing tape acts a lubricant that keeps
the temperatue down.

On Sun, 28 Aug 2011 19:51:44 -0700 (PDT), Hoosierpopi
wrote:

One issue with cutting templates (for my router, etc.) out of plastic
is the heat generated by the blade and the resulting melting (and,
then fusing) of the material behind the cut.

I had a paper pattern spay-glued to the sheet of salvaged 3/16"
plastic (from an old Staples Display Rack - great dumpster for
"finds") and I tried spraying a lubricant ahead of the cut line. The
paper pattern absorbed the oily/waxy spray and the cut material fell
away leaving a clean cut behind. I had switched to a blade with fewer
teeth (as I didn't have one of those plastic slicing blades on hand
and thought reducing the number of teeth might do the trick before I
thought of the oil spray).

THe stuff I used was foamy/waxy as opposed to the fine clear spray of
a WD-40, say. I cannot say if WD-40 would have worked as well and
cannot recall what the stuff I used was called. But The difference was
so impressive that I thought to post it here FYI.

In ,
Hoosierpopi typed:
One issue with cutting templates (for my router, etc.)
out of plastic is the heat generated by the blade and the
resulting melting (and, then fusing) of the material
behind the cut.

I had a paper pattern spay-glued to the sheet of salvaged
3/16" plastic (from an old Staples Display Rack - great
dumpster for "finds") and I tried spraying a lubricant
ahead of the cut line. The paper pattern absorbed the
oily/waxy spray and the cut material fell away leaving a
clean cut behind. I had switched to a blade with fewer
teeth (as I didn't have one of those plastic slicing
blades on hand and thought reducing the number of teeth
might do the trick before I thought of the oil spray).

THe stuff I used was foamy/waxy as opposed to the fine
clear spray of a WD-40, say. I cannot say if WD-40 would
have worked as well and cannot recall what the stuff I
used was called. But The difference was so impressive
that I thought to post it here FYI.

I still use the score & snap method unless it's not straight lines. I never
had much luck with jig-saws but my bandsaw with a fine-tooth design works
well as long as you keep the speed of the feed constant and fast enough to
avoid the heat buildup. For longish cuts, I'll sandwich the plexi between
two pieces of 1/8" Luan and cut away. Another little trick on the table saw
is to install a non-carbide blade backwards & make the feed rate fairly
fast. Takes a little practice to get the feed speed right but it'll work
well for long cuts. The main thing is to simply not allow the heat to build
up durinig the cut. The Luan sandwich works best for that. For me, anyway.
I don't know about WD-40, and had never considered anything like that,
but cuttinng oil along the cut path might work well to pull heat away too.
I'll have to play with that & see what happens.

Luck,

Twayne`

On Sun, 28 Aug 2011 19:51:44 -0700 (PDT), Hoosierpopi
wrote:

One issue with cutting templates (for my router, etc.) out of plastic
is the heat generated by the blade and the resulting melting (and,
then fusing) of the material behind the cut.

I had a paper pattern spay-glued to the sheet of salvaged 3/16"
plastic (from an old Staples Display Rack - great dumpster for
"finds") and I tried spraying a lubricant ahead of the cut line. The
paper pattern absorbed the oily/waxy spray and the cut material fell
away leaving a clean cut behind. I had switched to a blade with fewer
teeth (as I didn't have one of those plastic slicing blades on hand
and thought reducing the number of teeth might do the trick before I
thought of the oil spray).

THe stuff I used was foamy/waxy as opposed to the fine clear spray of
a WD-40, say. I cannot say if WD-40 would have worked as well and
cannot recall what the stuff I used was called. But The difference was
so impressive that I thought to post it here FYI.

I have a "carborumdum wire" abrasive blade for my jigsaw, but it melts the
plastic as well.

I use a foaming metal-cutting oil and it works quite well.

I've cut lexan and plexiglass fairly well on a TS, but what gets me
is drilling the damn stuff. I built a tablesaw guard out of Lexan,
and wanted to drill and tap the pieces together. No luck -- got several
drill bits stuck, two broke off.

-- Andy Barss

"Andrew Barss" wrote:

I've cut lexan and plexiglass fairly well on a TS, but what gets me
is drilling the damn stuff. I built a tablesaw guard out of Lexan,
and wanted to drill and tap the pieces together. No luck -- got
several
drill bits stuck, two broke off.
------------------------------------

Time to visit your local plastics distributor.

They will have the tooling to handle plastics.

Drill bits require special relief angles.

Lew

On Thu, 01 Sep 2011 23:36:15 +0000, Andrew Barss wrote:

I've cut lexan and plexiglass fairly well on a TS, but what gets me is
drilling the damn stuff. I built a tablesaw guard out of Lexan, and
wanted to drill and tap the pieces together. No luck -- got several
drill bits stuck, two broke off.

I've had pretty good luck by sandwiching the plastic between two layers
of plywood (or scrap wood). I used brad point bits at the lowest speed.

I've heard of these special bits but haven't used them:

http://www.rplastics.com/plasticdrill.html

--
Intelligence is an experiment that failed - G. B. Shaw

On 9/1/2011 4:36 PM, Andrew Barss wrote:
I've cut lexan and plexiglass fairly well on a TS, but what gets me
is drilling the damn stuff. I built a tablesaw guard out of Lexan,
and wanted to drill and tap the pieces together. No luck -- got several
drill bits stuck, two broke off.

-- Andy Barss

Negative rake on the drill bit and plenty of kerosene. Drills easily.

"Andrew Barss" wrote in message
...
I've cut lexan and plexiglass fairly well on a TS, but what gets me
is drilling the damn stuff. I built a tablesaw guard out of Lexan,
and wanted to drill and tap the pieces together. No luck -- got several
drill bits stuck, two broke off.

-- Andy Barss


It's the positive rake angle on standard metal cutting bits that is the culprit.
It makes the bit want to dig in, and for steel that's good. A zero rake angle
is needed for plastic to keep it from digging in. A drill bit made for brass
has the needed zero angle. You can modify a standard metal bit by grinding
a small flat, 1/16" is sufficient, on the inside (in the flute) of the cutting edge.
This flat needs to be in line with the axis of the bit.
Art

"CW" wrote

Negative rake on the drill bit and plenty of kerosene. Drills easily.


What he said. You can modify a regular bit with a dremmel with a cut-off
wheel. It only needs to be a couple degrees negative, which you can do by
grinding the leading edge of the cutting edge straight up and down, or a
couple degrees backwards from what the angle is now.

-- Jim in NC

Lew Hodgett wrote:

: "Andrew Barss" wrote:

I have had bad times trying to drill Lexan:
------------------------------------

: Time to visit your local plastics distributor.

: They will have the tooling to handle plastics.

: Drill bits require special relief angles.

: Lew

Thanks, Lew (& Larry, and the others downthread) -- very useful
tip, and I'll give it a go with these --

Andy Barss

"Artemus" wrote in :


"Andrew Barss" wrote in message
...
I've cut lexan and plexiglass fairly well on a TS, but what gets me
is drilling the damn stuff. I built a tablesaw guard out of Lexan,
and wanted to drill and tap the pieces together. No luck -- got
several drill bits stuck, two broke off.

-- Andy Barss


It's the positive rake angle on standard metal cutting bits that is
the culprit. It makes the bit want to dig in, and for steel that's
good. A zero rake angle is needed for plastic to keep it from digging
in. A drill bit made for brass has the needed zero angle. You can
modify a standard metal bit by grinding a small flat, 1/16" is
sufficient, on the inside (in the flute) of the cutting edge. This
flat needs to be in line with the axis of the bit. Art

They aren't true zero-rake, but you can buy "slow twist" drill bits that
come close. They are available in a much wider range of sizes than the
special "plastic" drill bits. They work very nicely on all plastics, as
well as brass. Mcmaster Carr sells them.

Doug White

If anyone is nearby in the Maryland area, I'd be glad to make some custom
plexiglass patterns for them with my Laser engraver. It is capable of
anything up to 24"x18", and I can create whatever shape you may need. Feel
free to contact me to work out the details.
Kevin