How do you clean up a hole cut in plexiglass?

[Judaeus Apella]

Say I used a 4-1/2" hole saw to cut out some fan holes in a new plexiglass window, how would I clean up the edges so they look clean and professional? No haze, scratches, or uneven edges? Maybe sand the edges, just enough to remove the burrs and even out the edges, then use Novus? I'm only guessing here. I don't want rounded edges, I want clean cut professional looking edges.

Are there any really decent 4-1/2" carbide tipped hole saws I can get without spending much more than $30? Would a bi-metal blade work on a steel case, or would I need something else? Would I need carbide blades?

(I'm thinking about pulling my old Temjin 5 out of storage and modding it. You know, fans on the top, fans on the side, add a window, clean up the main intake and exhaust with some wire cutters and a dremel, etc.)

Edit: Also, is this a good quality hole saw for $30? I looked it up on the Irwin chart here, its 4-1/2". Would it cut through 0.8mm SECC?
http://www.newegg.com/Product/Produc...9SIA058000CNV1

[chinaguy]

Yes you need to sand down with smaller and smaller sand paper then use Brasso and bits of card to polish away the marks of the sand paper.

http://en.wikipedia.org/wiki/Brasso

Put some Brasso on a bit of hard and start to rub the area of plexiglass until the marks are gone.

[Judaeus Apella]

On a bit of hard? Hard what? And what's the cardboard for?

[chinaguy]

Ops, typo! You put the Brasso onto the card and use that to polish to pelxiglass. You can get a plexiglass polish that dose the same.

The card acts as a fine glasspaper and polishes the plexiglass to a smorth surface.

1. Apply the Brasso to the card, or pad, or whatever you will be using to polish.
2. A tiny amount of Brasso goes a long, long, way.
3. Apply it gently, rubbing in small, controlled circles.
4. The Brasso may (will) turn black as you use/rub with it, this is normal.
5. The Brasso will turn white and "chalky" as it dries.
REPEAT UNTIL

[Judaeus Apella]

Card? Cardboard right?

Okay, cool. Thanks. That really helps me. Less things to buy. I'm sure we have some Brasso sitting around the house somewhere, if not its cheap and easy to get.

So back to my second question topic:

Are there any really decent 4-1/2" carbide tipped hole saws I can get without spending much more than $30? Would a bi-metal blade work on a steel case, or would I need something else? Would I need carbide blades?

Edit: Also, is this a good quality hole saw for $30? I looked it up on the Irwin chart here, its 4-1/2". Would it cut through 0.8mm SECC?
http://www.newegg.com/Product/Produc...9SIA058000CNV1

I don't want to buy more than one blade. I'd like to buy one that can handle metal and plastic. There's a picture on that second page link, of them using that product to cut through a piece of metal, but it doesn't say if its aluminum or steel they're cutting through. It looks like steel, but I can't be certain and I have no idea what those numbers mean.



I haven't messed around with metal cutting in a while, and I don't remember which blade materials do what. I know carbide is one of the top materials but as I recall its easier to damage than a standard bi-metal blade, as the teeth can come off like on some circular saw blades I've had to toss in the metal crap box. As I recall I think carbide is for softer materials? I can't recall. So I need to know what to use on a Temjin 05. It is not an aluminum case, its made out of 0.8mm SECC. Only the front of the case is made from aluminum.

[Manicdan]

the hole saw you were looking at seems near identical to the one i use, and those curved teeth are utter crap when it comes to clean cutting

i have an edge cleaner :http://www.frametek.com/HTML/Other/A...e_Scraper.html
and it does a good job, but sadly on a curve like that it takes a while and with those crappy hole saws it might not be possible
i was actually thinking of taking my hole saw and running it while i sand down the outer edge

once the edge is cleaned up you burn it with a torch. a weak butane torch works nicely, and it will take a little practice to know how hot and how slow to move it across your surface. but it comes out looking near perfect. it also helps round the edges, so dont do that beforehand with the edge cleaner.

EDIT: this is for acrylic, not lexan

[Judaeus Apella]

the hole saw you were looking at seems near identical to the one i use, and those curved teeth are utter crap when it comes to clean cutting

i have an edge cleaner :http://www.frametek.com/HTML/Other/A...e_Scraper.html
and it does a good job, but sadly on a curve like that it takes a while and with those crappy hole saws it might not be possible
i was actually thinking of taking my hole saw and running it while i sand down the outer edge

once the edge is cleaned up you burn it with a torch. a weak butane torch works nicely, and it will take a little practice to know how hot and how slow to move it across your surface. but it comes out looking near perfect. it also helps round the edges, so dont do that beforehand with the edge cleaner.

EDIT: this is for acrylic, not lexan

I don't want rounded edges, I want clean cut professional looking edges.

*sigh*

[Manicdan]

*sigh*

i know you said that which is why i mentioned that it does HELP round edges.
when cutting your going to get sharp edges, ive cut myself plenty of times on sharp edges, so you might actually want to clean them a little so they feel better, but look nearly the same.
melting acrylic can yield different results when done different ways, im just trying to provide options.

[Judaeus Apella]

Okay, now I see where you're going. You're saying to use it like a deburring tool, but not enough to actually make the cut round.

Now that that's out of the way, back to my questions about saw blades. If I want to cut both metal and plexiglass, what would be a good choice in blade type? It HAS to come in 4-1/2", or it won't work for me. So please consider that before making a suggestion.

Thanks for the help so far guys!

[Manicdan]

Okay, now I see where you're going. You're saying to use it like a deburring tool, but not enough to actually make the cut round.

Now that that's out of the way, back to my questions about saw blades. If I want to cut both metal and plexiglass, what would be a good choice in blade type? It HAS to come in 4-1/2", or it won't work for me. So please consider that before making a suggestion.

Thanks for the help so far guys!

i doubt you will find a NICE hole saw for that price. the style of those teeth is just not good enough for a clean cut (they are mostly designed for soft wood)
IF you want to improve the cut quality you can try (at your own risk), put the hole saw in a drill press and turn it on. then use a fine file on the outside edge and the outer most teeth might be cleaned up enough to remove most of the bad scraping. also if you do try this, put the drill in reverse so its not trying to pull on the file

thats the only idea i really have.
found this btw
http://www.xoxideforums.com/guides-t...les-guide.html
they simply recommend any bi-metal hole saw for case modding. i guess due to how thin it is, theres not much of an issue.