cleaning Lexan parts 2

[cambria]

We have a few thousand devices out in the field with bodies made with Lexan. At a couple of large installations we found the client with metal housings around the devices - because "they were getting hit". Comes out they have bee routinely spraying with cleansers of various types, effectively dissolving the devices. It is an optical application, environment is dust and perhaps very thin oil from machinery running in proximity: whats a good solution for those clients compelled to clean?

 

[MikeHalloran]

Acrylic?
ABS?
SAN?
Polysulfone?
Clear silicone boots?
NASCAR/ dirtbike "tear-offs"?




Mike Halloran
Pembroke Pines, FL, USA

 

[cambria]

Lexan 121. Precision IR optical device. Custom additive. Not consumer. Not industrial.

 

[patprimmer]

Lexan is GE's trade name for their polycarbonate.

Polycarbonate is very sensitive to solvent stress cracking with chlorinated and aromatic hydrocarbons. Most lubricating oils have some aromatics present. Cleaning chemicals can often also contain solvents that attack polycarbonate. GE should be able to provide a list of suitable cleaning agents, but this won't undo damage done by lubricating oil.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[MikeHalloran]

If I remember correctly, the list of cleaning agents that _are_ suitable for PC is pretty short, and doesn't include a lot of stuff that you'd think was innocuous. If you've got oil in the air, PC is not a good choice.


Instructive experiment: Get a sheet of thin PC, cut it into strips say 25mm x 150mm. Remove the protective film.

Take a strip and bend it with your hands. With some difficulty, you can fold it back on itself without it breaking or cracking. Amazing stuff.

Take a similar strip and dip it in some solvent, as briefly as you can. Wipe it off. Try the same test. It will snap like styrene. Amazing, in a different way.



Mike Halloran
Pembroke Pines, FL, USA

 

[cambria]

Thanks, yes chemically induced stress cracking is an amazing thing. On top of it, hydrocarbon vapors are even more destructive that way than the fluid, and the fracture propagation sometimes goes beyond belief. This is one of those practical issues - we have told them "dont do that" of course, and I get the same response as I do from my kids.

The dominant issue is dust. The solution is vacuuming but there is an innate desire to wipe something up. I was thinking water/vinegar, but this is not a real winner. Put a surface charge on the Lexan? maybe there is no real solution.

 

[MikeHalloran]

I'd test Rain-X and (original)Pam, just for fun.



Mike Halloran
Pembroke Pines, FL, USA

 

[MacGyverS2000]

Look for a product called Plexus (spray can). You can find it in some of the better boat/marine stores and high-end motorcycle shops. It's used for cleaning PC windshields (I use it to clean the Lexan windscreen in my convertible). Figure about $8-10/can.


Dan - Owner

http://www.Hi-TecDesigns.com