lexan or plexiglass?

[reinhardt]

recently i posted a thread asking for advice on how to build some 'soffit cabinets'. i want to put either lexan or plexiglass sliding doors on the cabinets similar to jack olsen's. doors will be about 18" high by dunno how wide, maybe 36". how thick do i need to use? what is the difference between lexan and plexiglass? the cabinets will be against the ceiling, so i don't think they will get scratched up or anything. the price difference is double! 36x72 sheet of plexiglass is $50, while lexan is $100 at home depot.

ben

 

[Possum]

Lexan is a trademark name for polycarbonate and Plexiglass is a trademark name for cast acrylic. A quick google search should provide you with some info to decide which will work best in your situation. Polycarbonate is more impact resistant, acrylic more scratch resistant.

 

[Daddy_Rabbit]

plexiglass is acrylic and will shatter whereas lexan is polycarbonate and is for the most part impact-resistant.

 

[Jay H 237]

Polycarbonate (Lexan) is shatter resistant, it will actually bend and stuff will bounce off it if hit. Cast acrylic (Plexi-glass) will shatter and crack if hit or bent bad. Both will scratch.


(Where I work the robotic workcells we sell require Lexan guarding fully around them. If anything ever goes wrong and the guarding takes a hit the Lexan won't shatter and allow anything out of the workcell)

 

[OccupantRJ]

I demonstrate the difference with new hires by giving them a 2 inch square of each material 1/4" thick, along with the proper safety gear and a 20 oz ball pein hammer. The samples are placed on a thick steel table. They are then instructed to break the plexi, which will shatter in one strike. They are then told to do the same to the polycarbonate, but they never succeed before their arm tires out. The polycarbonate dents and gets hot, but doesn't break. Either material is easily sawed with common tools. I use the polycarbonate for see thru machine guarding. Certain chemicals exposure are not good for either product.

 

[rsanter]

plexi will be fine for what you want

bob

 

[Jack Olsen]

Lexan is better for safety-sensitive applications, like a race car.

In your shoes, I would get the Plexiglass. But get it cut to the size you want. It's not easy to cut without damaging/splitting/ruining it.

 

[snowphun]

I used to be frustrated with cutting plexi and lexan, but it really is pretty easy. Pick up one of the $2 scoring tools they sell near the material, score along a straight edge 5 or 10 times (overkill) then (IMO the key part) clamp to the edge of a table with a piece of lumber above to prevent the piece from flexing. Give it a wack with your palm and it'll snap on the line. I've been dozens of picture frames and haven't had any issues in years.

 

[irishtom]

Early in my architecture career, I used to make a lot of scale models of buildings and used a lot of plexiglass. We used plexi knives like snowphun describes. If the plex was thicker, we'd score both sides before snapping. We also would use a veneer blade on the table saw to cut thicker sheets.

 

[reinhardt]

thanks for the info guys. plexiglass it is. i'll see if i can get hd to cut it. anyone know a cheaper source? i need 7 pieces 18"x36". i know it's crazy to buy steel from hd, thinking same may go for plexi. anyone got a good source?

ben

 

[Kevin54]

In all my years off tool & die and modelmaking I found out something about Lexan that I never knew. I was making an adapter for a centrifugal paint shaker. I made two plates with an ABD piece of tubing in between and screwed the Lexan to the tubing. Never ever use LocTite on Lexan. It split it out from each hole in a dozen different directions.

After reading about the Loctite it states that it may not work on some polycarbonate.

 

[stafford]

Lexan is much more expensive too.

 

[Jay H 237]

In all my years off tool & die and modelmaking I found out something about Lexan that I never knew. I was making an adapter for a centrifugal paint shaker. I made two plates with an ABD piece of tubing in between and screwed the Lexan to the tubing. Never ever use LocTite on Lexan. It split it out from each hole in a dozen different directions.

After reading about the Loctite it states that it may not work on some polycarbonate.

What I have done when working with plastics and having to screw into them at times is use teflon tape on the screws. It will 'gum' the threads enough that they stay in vibration enviroments but the screws and teflon will still come out if needed.

 

[Warrenator]

Quick tip, while at the plastic store buy a can of Plexus plastic cleaner to clean it with, never hit it with windex. Or lemony fresh pledge works fine. Use a cloth towel, not paper.

Use the scoring tool described by Snowfun to cut it, if you are going to drill holes for handles get one of the plexiglas drills they sell at the plastic store, they have a different relief angle than a regular metal drill and will not crack or split.

 

[reinhardt]

anyone know if i could pay a shop to cut the plexiglass to size and drill the holes for handles for me at a reasonable price? i am super cheap so i typically do things myself, but if i waste a bunch of plexi doing it wrong i'm not saving myself any money.

 

[Warrenator]

You won't do it wrong, it's super easy, just be patient and get the correct drill for the holes. The drills are like 2 bucks. If they cut it they want like $3 per cut, at least at my place in San Diego, and then more to flame polish the edges. (Only on super thick pieces do you want that) I usually just score it and snap it, or use a jigsaw on super thick pieces. I also have used 800 grit sandpaper, wet, to take the shreds and burrs off the edges. A link for you: http://www.gearhack.com/myink/ViewPage.php?file=docs/Cutting Plexiglass

 

[noboD]

Cut it on a table saw, we do it all the time at work.

 

[Vinko]

Cut it on a table saw, we do it all the time at work.

Yeah, I use a blade designed for it (among other things) by Freud.

In my experience, plastic shops have better pricing and selection than Home Depot. Perhaps not as convenient in your area. I don't know.

 

[V-10 Killer]

I've cracked a few pieces of plexiglass trying to drill through, even being extremely careful.
I know it sounds crazy, but I've had luck drilling thru plexiglass by running the drill in reverse. You're actually melting thru via friction, but you won't crack it. then just clean up the hole with a large bit or cutting tool of your choice.