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Lexan question

N

n00btard

Gawd
Joined
Dec 10, 2005
Messages
922
So I want to make myself a Lexan case. Because lexan is tougher than acrylic (but not as scratch resistant, but oh well...) and I heard scare stories about fire hazards associated with acrylic (two-hundred-something degrees centigrade for melting point, 54 degrees centigrade flashpoint once it's melted, or something like that) and I'm hoping it doesn't carry over to lexan. Froogle search shows that lexan is pretty cheap too.

So anyways, I haven't been able to find any lexan sheets with a thickness over 0.08", which is like, 1mm. Is that rigid enough to make a case? I keep seeing acrylic cases made with 6mm sheets, but I'm not sure if 1mm lexan is just as strong as 6mm acrylic...

Speaking of "strong," is lexan really flexible and give the case a rather flimsy characteristic, or does it not flex at all at 1mm thickness?

Thanks in advance
 
I know what you mean, once it reaches 190 here in pittsbugh, I worry about my acrylic case window just going POOOF. Like spontaneous combustion man its so crazy. :confused:
 
No way. 1mm of Lexan will snap if you look at it the wrong way :). My suggestion is 4-5mm Lexan plastic.

Why lexan? I find it easier to bend and drill, not to mention that it doesn't attract dust as well as Plexi. Also, it won't yellow, a siginificant upside if you're going to keep the case around for awhile.

I'm assuming you know how to cut this stuff?

Um... I can guarentee the flashpoint of melted lexan isn't 54c. When cutting the stuff it melts quite easily, and gets way hotter than that. Maybe for fully molten plastic... But nothing you're going to encounter through bending/drilling it.

And ps, if your case ambient temp is above 50c you have a SERIOUS problem :).
 
Arcygenical said:
No way. 1mm of Lexan will snap if you look at it the wrong way :). My suggestion is 4-5mm Lexan plastic.

Why lexan? I find it easier to bend and drill, not to mention that it doesn't attract dust as well as Plexi. Also, it won't yellow, a siginificant upside if you're going to keep the case around for awhile.

I'm assuming you know how to cut this stuff?

Um... I can guarentee the flashpoint of melted lexan isn't 54c. When cutting the stuff it melts quite easily, and gets way hotter than that. Maybe for fully molten plastic... But nothing you're going to encounter through bending/drilling it.

And ps, if your case ambient temp is above 50c you have a SERIOUS problem :).
Click to expand...

The temp thing was for acrylic, which I pulled from NCIX forums.

Can you tell me where to buy lexan panels 4~5mm thick? Case is going to be about 15"x14"x10"

I heard that you can just score it with one of those retractable cutting blade thingies and snapping it, and I'm going to mooch a dremel off my friend for other cutting jobs.
 
Home depot works well for me :). Fairly cheap too. Yep, scoring it works really well, buy a tool made for the job, they're usually better than other household tools.
 
I havent worked with lexan, but acrylic does not ignite at 54 C. Acrylic softens and becomes formable at 190 C but does not self ignite until 490 degrees C, which is almost 1000 degrees farenheit. Neither of which you will ever encounter in a household unless its in your oven. Quality acrylic does not yellow either. Most cast acrylic shows no yellowing even after being subject to 10 years of UV light. There are a couple hundred different types of acrylic and each has its own traits and characteristics. For acrylic, I would recommend cast acrylic, 3/16 of an inch thick. Most plastics are metric though so its about .177 thick.
 
As for lexan, I chose it because my friend keeps bashing the shit out of his lexan Nalgene bottle against lockers and keeps stuffing it down his pants during lunch to make us lose our appetites, and I've have multiple times where I've accidentally dropped my own Nalgene bottle onto the ground while riding my bike, so I was quite impressed with its strength.

Would 1/4" lexan be strong enough to make a case with? I don't want the damn thing to be flexing AT ALL, and it's going to be held together completely by little acrylic cube thingies you can buy at Mountain Mods. If I decided to make the case with 3/8" lexan instead, would that prevent the case from flexing at all? Or would the thing be too damn heavy to move around? I want it to be a LAN rig and I want to be able to see the WC circuit clearly. Not sure if 3/8" thickness will cause some haziness and blur the view to whatever's on the other side of the sheet.
 
1/4' lexan would be very rigid, and heavy (18lbs for the average case or so). Lexan of almost any thickness won't haze, unless you scratch it... so keep the protective plastic on till the very end! Ummm... what else, well drill and cut slowly, the slower the better, it'll discourage melting.

Also, you might want to make sure that, when you screw into the lexan, you go verrrry slow, with wood screws first, or else you risk cracking it. :eek:
 
I personally wouldn't try to thread screws into lexan, it doesn't have a lot of tolerance for that and tends to crack, sometimes months later. It's better to drill through and use nuts on the back.

A great source for all all things polycarbonate (Lexan) and acrylic is US Plastics. I've ordered from them several times and they're very nice to deal with.

They have a huge range of acrylic products, especially hard to find stuff.
 
Home Depot would be cheaper after shipping, and a lot easier to get the right amount from. I have bought Lexan from Home Depot before and it worked out fine. 1/4" Lexan is probably about right for the thickness of the case.

Agent is completely right about the screw thing. NEVER thread screws into plexi or lexan. Instead, use a screw and nut and carefully drill a hole for the screw.
 
you can thread acrylic for light tension applications, like thumb screws, but it should be at least 1/4 inch or so.
 
So I should hold the thing together with L-shaped brackets, and since I can't hold the nut from the inside while unscrewing the bolt from the outside once the case is completely closed, I superglue the nut to the L-bracket, once I drill the holes in the brackets?
 
to hold it all together its best to have cubes, of acrylic or whatever with a hole on 3 sides tapped for the screw you want to use, then put it in the corner of the joints and screw the 3 panels to it. you will have to drill a clearance hole in the acrylic panel.

for drilling acrylic use a negative rake drill bit. they are available at www.mcmaster.com called plexi drills or something.
 
Get Lexan from Mcmaster, it's pretty cheap and they have the best shipping service ever. The lexan you will find from Home Depot is .09 (3/32"), which is slightly under 1/8"(.125"). I would use 3/16"-1/4" lexan for a computer case. You CAN thread lexan, as long as you do it right. The tapping oil's you use to tap aluminum/steel/titanium will have an effect on lexan over time that will cause it to crack under impact, so when tapping it just use water, or nothing at all and go slow. As for cutting it, you can use blades made for cutting wood on a tablesaw or a scrollsaw ect.
 
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