Lubricant cracks clear polycarbonate

[alansimpson]

I use clear polycarbonate as an engineering material for test fixtures. I understand some oils and machining lubricant will cause cracking.

Could anybody recommend light lubricating oil that will not have this effect?

Just lubricating moving parts.


Thanks

 

[patprimmer]

Silicone oil.

Good clean pure water.

Water and dish washing liquid (The Palmolive type).

Definitely not mineral oils as even if labelled paraffin, they contain some aromatics as impurities.

Nothing containing halogenated hydrocarbons or aromatic solvents or keytones.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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[Demon3]

Worth mentioning that PC is the very worst plastic in the planet for ESCR. If you don't need the high impact resistance that PC offers, then you can use another plastic such as PS, SAN (both brittle). MABS is one good option.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[Pud]

Clear PVC anyone?

I would guess the op needs it in sheet form to fabricate stuff?
If it is sheet then PC sheet is not too bad if used in an unstressed application as it has no residual stress in it.

There's also the dry lubricant option - Graphite, PTFE, MoS2 etc...

http://www.tynevalleyplastics.co.uk

 

[CoryPad]

For the applications mentioned by Demon3 and Pud, why is PET not the first choice?

 

[Demon3]

Yes, I agree, I nearly mentioned PET and PVC, both good options.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[Pud]

Corypad, I actually tried to think of the "other" one whilst writing the previous reply and could not just recall it. Easy, of course once you know the answer. It's all there you know - it's just the recall system that's getting flakey!

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

The OP states he used clear PC. He gives zero reason for his choice so clear may not even be a requirement. He says it is a test fixture. Obviously the test involves lubrication, but we have no idea of temperatures or load or evironment.

There may be any other number of un-stated requirements so we could guess anything.

I fully agree another plastic that meets his requirements would be a very good idea.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules