[ 3 / biz / cgl / ck / diy / fa / ic / jp / lit / sci / vr / vt ] [ index / top / reports ] [ become a patron ] [ status ]
2023-11: Warosu is now out of extended maintenance.

/diy/ - Do It Yourself

View post   
File: 6 KB, 456x361, Untitled.png [View same] [iqdb] [saucenao] [google]
467518 No.467518 [Reply] [Original]

Hi /diy/

Quick question

Building an electronic enclosure, needs a switch mounting. The switch is being mounted into a 6mm thick polycarbonate sheet.

How do I cut into the sheet? Tried a saw, just stuck and then cracked the sheet.

Pic related.

>> No.467520

>>467518
With a dremel.

>> No.467522

>>467520
/thread

Answered.

Thankyou.

>> No.467590

>>cracked the 6mm sheet.
Then your sheet isn't polycarbonate. Cracking polycarbonate that thick would take a hell of a lot of strain or degredation.
I've only managed to crack polycarbonate under compressive loads over time or by compromising it with chemical exposure to alcohols or petroleum byproducts.
>>467520
Actually no. Abrasive tools are terrible for cutting most plastics.

If you want to cut a square hole in polycarbonate you need to drill a pilot hole then finish your cut with a scroll saw or coping saw.

>> No.467595

>>467518
Sabre saw.

>> No.467598

>>467590

PC Plastics HATE pressure applied perpendicular to their thinnest side, very much like HDPE with a recycling number of 2 (typically found in cat litter buckets and food-storing buckets.)

Dremels might be horrible but they work very well and leave a 'clean' cut if you know what you're doing (aka use a low rotational speed to avoid friction-welding of plastic, typically 2-4 setting, use the regular plastic/wood cutting discs instead of a metal cutting disc, etc.) They also will be far less likely to break the plastic due to the abrasive nature of the disc, and not the wedge nature of the saw

Using a scroll saw or coping saw on PC plastic is a BAD idea unless the blades are very fresh and sharp, and the cutting surface for such has a narrow slit to prevent the plastic from bowing at the cut area and snapping apart from mechanical force, otherwise even the slightest bind will crate a stress crack and then the plastic will shatter.

Source: Former wood/plastics/metal shop teacher that handled the school's theatre department construction needs.

>> No.467691
File: 70 KB, 800x600, ABP5K.jpg [View same] [iqdb] [saucenao] [google]
467691

>>467598
>>Using a scroll saw or coping saw on PC plastic is a BAD idea
Really? I do it all the time. For the past 10 years in fact.
And OP said he's cutting 6mm thick sheets. That's just under 1/4" and most of what I've made was out of that same thickness.
Such a thick sheet isn't going to bow around the blade at all.

If he's cutting thin sheets of acrylic (which isn't what he stated) then yes he needs to be more wary of tooth counts, feed rates, and spm settings when cutting it wit ha scroll saw. I have plenty of practice with that too.

Cutting plastics effectively is about having the right tooth count and cutting speed.
>>stress crack
You don't get those when cutting Polycarbonate because it's too ductile to fracture.
You get those when cutting acrylic ("plexiglass") which people tend to confuse with polycarbonate because they're sold alongside each other.

You might rip off chunks of polycarbonate if you were to try cutting it in a table saw with a wood blade.

>> No.467693
File: 44 KB, 480x640, nmp_998.jpg [View same] [iqdb] [saucenao] [google]
467693

Here's some white acrylic I cut with a scroll saw.

>> No.467714

dremel foo

>> No.467716

Dremel with milling bit...

Or just a Hotknife

>> No.467897
File: 51 KB, 585x340, 1370262126754.jpg [View same] [iqdb] [saucenao] [google]
467897

i use this nibbling tool

>> No.467902

>>467518

Drill and coping saw or chain drill and file.

>> No.467907

I would drill 4 holes near the corners of the area to be removed and then use a coping saw with a blade for wood, narrow so it can be controlled more easily where you're going and with a wide kerf, so it doesn't bind, advancing into the cut slowly.
I would leave a couple millimeters around to be removed later with a fine file, so the edges are perfectly straight and clean.

>> No.467966

>>467518
a common problem when hand-sawing (or power-cutting) plastics is that the plastic heats up, then sticks to the saw blade. Often the plastic cracks shortly thereafter.

You can't use water with electric saws but it can help a lot to have someone else hold a hose running a small trickle of water over where you are hand-sawing, as you saw. The saw blade needs to always stay cool.

Nibblers can work also, but some types can get jammed up if the plastic can compress during cutting. There's like 2 or 3 different basic types of hand-nibblers, and it is worthwhile to have one of each kind. Also they are ONLY for softer metals and plastics. They are not built strong enough & hard enough to cut steel, don't bother trying. You'll just ruin the nibbler.

>> No.468079

>>467907

Drill holes in a grid and use a milling bit or file (or may be hot wire?) to connect them together. Do some light filing so that the switch can fit through.

Most of the panel switch have retainers and are pushed in from the front. The front part is larger than the hole, so it can cover some no so neat filing jobs. ;)

>> No.468184

> They are not built strong enough & hard enough to cut steel, don't bother trying. You'll just ruin the nibbler.

I used a Radio Shack nibbler for 10 years, usually on 20 gauge steel, but sometimes up to 18 gauge, before it broke.

>> No.468199

I fill an old cake pan with cold water, put the plastic over the pan, and cut with a jigsaw. the water keeps the blade cool enough so it doesnt bind. also, I stop often, and touch the blade to see if it's hot. this technique is very low effort, and fairly quick by comparison with other methods described here.