tinted polycarbonate is a poor electrical insulator?

[hillzofvalp]

I'm confused. What kind of issues is mcmaster talking about for this bronze tinted polycarbonate sheeting?

http://www.mcmaster.com/#87245K114

Color: See below
Temperature Range: -40° to 200° F
Softening Temperature: 295° F
Tensile Strength: Good
Impact Strength: Excellent
Poor electrical insulator
Use indoors and outdoors
Machine with high-speed steel tooling
Hardness: Not rated

 

[amberwolf]

If it's tinted using metallic coatings, it won't be a good insulator. If it's just metal particles embedded in it, then it depends on how far apart they are within the plastic as to how high a voltage it might take. I don't know what kind of insulation factor PC has anyway.

 

[Drunkskunk]

vaccume metalizing may have been used for the bronze tint, or they may have used carbon black for tinting. Either would make it a conductor.

 

[hillzofvalp]

I guess I wonder how much current can go through it before something burns up.

I'm planing on doing a major revision to the clear polycarbonate panels I currently have on my bike. Technically no bare wires contact it, but In the event of a freak failure I'd like to know the consequences.

I also wonder how "scratch-resistant" is "scratch-resistant." I would love it if it didn't scratch so easily.

 

[www.recumbents.com]

Just spraypaint the inside of your clear panels. It will look very nice, and the paint will never scratch!

-Warren.

 

[hillzofvalp]

What about the outside? that's the area that is most prone, obviously.. can I coat it with something special? minimal flexing will occur

 

[fechter]

I don't think you need to worry about the conductivity, just don't put uninsulated wires against it.

They make a film coating that resembles window tint that is clear and very scratch resistant. Clear Bra is one that I've heard of. This is the same kind of film they use as screen protectors for cell phones and PDAs. I have some on my motorcycle tank. If you crash the bike, forget it, it's going to scratch anyway, but for leg rubbing it should hold up nicely. The stuff is not cheap though. Personally, I would just use a buffer on it once in a while. Car window tinting places have it.

 

[StudEbiker]

Are you not concerned with airflow to your controller? The tight confines, sealing it from any air flow whatsoever, plus removing the heat sinking case, seems to be a recipe for controller failure.

 

[Doctorbass]

What is the best is G10... it's like FR4 ( pcb) without copper.. and they sale them at mcmaster or ebay

Every of my battery pack are made with them.. and they dont spread flames.. and are very good electrical insulator!

 

[hillzofvalp]

I've considered the airflow issue..but my end goal is to be completely waterproof. The enclosure I machined (which doesn't have a top, so you can't see it in above picture) is actually beefier than the original enclosure. It is then heatsinked to the aluminum u channel framing with arctic silver. I guess we'll see how that works out? For a higher power setup >3500W peak I will get a bigger controller and mount it outside somewhere.


Thanks doc, but I'd like something prettier. That would be good to put in between my batteries for sure though.

 

[www.recumbents.com]

That's the beauty of painting the inside. You can beat the heck out of the outside, unpainted Lexan (polycarbonate) and it will still look great. Try it with some scrap pieces.

-Warren.