How conductive is lexan? - Page 1
Forum section: electronics / beginners

author: zeos
author_rank: Newbie
timestamp: May 11, 2015, 02:03:57 am
content: I bought a sheet of lexan to stick some breadboard on and have some extra space to put raspberry pi, arduino, etc. on. Is it safe to do this or should I put some of that pink foam that sometimes comes in computer motherboard packaging?

author: Monkeh
author_rank: Super Contributor
timestamp: May 11, 2015, 02:07:41 am
content: If you can't measure it..

author: babysitter
author_rank: Frequent Contributor
timestamp: May 11, 2015, 06:49:05 am
content: you might google it, but short: you can consider it to conduct at the "Not at all" level. High voltage breakdown needs some kV per mm thru it, resistance is better written as a number with exponent. Thats the clean, clear product, intense colors might get the resistance down.

author: Psi
author_rank: Super Contributor
timestamp: May 11, 2015, 06:52:51 am
content: The pink foam will be orders of magnitude more conductive than the lexan

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 11, 2015, 06:57:21 am
content: Indeed, your question is the wrong way around -- the pink stuff is millions to trillions of timesmoreconductive than most plastics! It's used to ship and storeunpoweredelectronics. Though almost everything will be okay operating in contact with it, anyway -- despite the difference, its resistivity is still usually measured in exponents too. So the in-circuit resistance between points touching the stuff will be in the gigaohms -- something no digital circuit would notice.I have a very different caution for you, actually -- be very careful cutting that stuff, it likes to crack like nobody's business. Or is that acrylic, or both? Both like to melt and gum up high speed cutting tools, too (drills, saws, etc.).Have fun,Tim

author: SL4P
author_rank: Super Contributor
timestamp: May 11, 2015, 07:01:22 am
content: I suspect the pink foam you're referring toisconductive!(megohms per inch) for dissipating static buildup.

author: Psi
author_rank: Super Contributor
timestamp: May 11, 2015, 07:21:28 am
content: Quote from: T3sl4co1l on May 11, 2015, 06:57:21 amAcrylic is the one that cracks when you look at it funny. Lexan/polycarbonte does like to melt and gum up the cutting tool though, as you say.

author: electr_peter
author_rank: Unknown
timestamp: May 11, 2015, 07:27:26 am
content: Don't worry about plastic, there will be no issues at all.I add small rubber feet stickers (used on furniture) on the bottom of the development boards so it does not scratch surfaces and does not short out on metal surfaces. It adds some bounciness and friction/resistance to forces from cables too.Quote from: T3sl4co1l on May 11, 2015, 06:57:21 amBe aware with transparent acrylic materials. Acrylic will crack on contact withany (!)chemical unless it is water or substance designed to be used on acrylic. This includes almost all types of glue, alcohols, loctites, etc (that is - anything other than water). Do not ask how I know...

author: OldNeurons
author_rank: Regular Contributor
timestamp: May 11, 2015, 08:27:33 am
content: Certainly no problem at all with resistivity which is in the range of 10E16 Ohms-cm.http://www.associatedplastics.com/forms/pc_lexan_9034.pdfI would be more cautious about static charges.

author: mzzj
author_rank: Super Contributor
timestamp: May 11, 2015, 09:58:34 am
content: Quote from: Psi on May 11, 2015, 07:21:28 amIMO Polycarbonate is very nice to work with sharp tools and wont melt easily. 12mm PC plate will cut easily with small handheld circular saw with good finish and drills nicely without worry of cracking.Acrylic (PMMA) is cracked easily and melts reasonably easily.Polystyrene is the royal pain in a.. will ether crack or gum on tooling, sometimes crack AND gum in the same time..

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: May 11, 2015, 10:21:33 am
content: actually polycarbonate is worse for solvent crazing than acrylic - keep ketone solvents far away unless you want a pile of chipshttp://www.theplasticshop.co.uk/plastic_technical_data_sheets/chemical_resistance_guide_polycarbonate_sheet.pdf

author: zeos
author_rank: Newbie
timestamp: May 11, 2015, 02:09:56 pm
content: Thank you for the info. I like the idea of adding feet.

author: macboy
author_rank: Super Contributor
timestamp: May 11, 2015, 02:14:44 pm
content: Quote from: SL4P on May 11, 2015, 07:01:22 amMany here assuming pink foam is conductive; it is not. It is "non static charge generating", meaning that it does not readily take on or give off electrons when rubbed against other things. This prevents static buildup which destroy electronics, but it is not conductive, and won't actually dissipate static charge like conductive products will. The shiny metalized (or black) plastic bags are conductive, the black open-cell foam that you stick dip ICs into is conductive, but pink bags and foam are not.

author: KJDS
author_rank: Super Contributor
timestamp: May 11, 2015, 02:28:35 pm
content: I do know that a brand new instrument, only one working in the world was about to be sent to the US and I saw that the screen was dirty so gave it a quick wipe with acetone.I then had a mad half hour finding and replacing the screen after it had completely frosted.Don't put any volts across black conductive foam. Actually, do put volts across it, but do that outdoors for fun, it combusts well.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 11, 2015, 03:19:15 pm
content: Quote from: f5r5e5d on May 11, 2015, 10:21:33 amAdd ammonia-based cleaners to the list - in particular spray window cleaners.Polycarbonate is tough on cutting tools. Stick to carbide-tipped if you can. Also keep the cutting speeds down to reduce melting.

author: jobog
author_rank: Regular Contributor
timestamp: May 11, 2015, 09:44:33 pm
content: I cut a lot of lexan sheet while working at Lowes part time. The best way is to score the sheet several times with a sharp knife and then snap the sheet, hold down one side and put pressure on the other, over the sharp corner of a board or table. Even the 1/4" stuff breaks very clean this way.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 11, 2015, 10:19:32 pm
content: Quote from: macboy on May 11, 2015, 02:14:44 pmMany, perhaps most, of the "pink foams" and static control plastics ARE static dissipating. They are often, perhaps always, not-conductive by EIA-541 definition of < 10^4 ohms, but many manufacturers claim static dissipating qualities which means resistance in range of 10^5 to 10^12 ohms per EIA.If you are really concerned about these qualities you need to know the vendor of your example of pink foam, and know what that vendor claims about their material. Whatever the theoretical arguments, I have had no known ESD issues with devices that have been shipped in, stored in or worked on pink foam. Can't say the same about devices that have had no ESD protection.