Soda bottle caps materials?

I have a possible hobby use for Coke bottle caps. These are various colors, translucent with a whitish liner on top.

Does anyone know the cap material and the lining material?

Reply to
Ken C
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There are many forms of cap liners:

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The plastic caps appear to be polypropylene:
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(An amateur scientist! I love it!)
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If big business and the greens agree on anything, it must be right!

John Aspen Research -

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"Turning Questions into Answers"

Opinions expressed herein are my own and may not represent those of my employer.

Reply to
john.spevacek

On 24 Jan 2006 11:35:47 -0800, " snipped-for-privacy@aspenresearch.com" >

Thank you.

There goes my app: If I recall, it is very difficult to bond anything to polypropylene. I had hoped to use epoxy.

Ken C

Reply to
Ken C

You could use acrylics.

Oliver

Reply to
Oliver 'Ojo' Bedford

Correct. PP is a difficult surface to adhere to, but there is hope.

Since this is a hobby application, you might want to consider flame treating - passing the bottle caps quickly through a flame. If done correctly, this will oxidize the surface and increase the adhesion. You will have to play around with this to get it right, but since you have a more or less unlimited supply of low cost caps, the only cost is your time and the wasted epoxy. By the way, this surface treatment fades over time (days or weeks, not minutes) so treat them and use them fairly quickly.

The caps of course will melt or burn if overheated and that can be hazardous to your health and happiness, so please act safely.

I'd be curious as to your successes/failures and also what the heck it is that you are building with pop bottle caps.

John Aspen Research -

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"Turning Questions into Answers"

Opinions expressed herein are my own and may not represent those of my employer.

Reply to
john.spevacek

I need a receptacle for 3-LED cluster (plus resistor and small PCB) that will illuminate a motorcycle engine but will block direct light to an observer.

I can't use a commercial LED product because none of the vendors/makers can tell me their rated luminosity and by law in NY I must keep it to under 32 CP for non-white lights. They seem to use pulsed LED's and their luminosity is in the 100 CP range (peak).

Also under consideration are the tiny tubs (1" diam)(styrene?) that Chinese take-outs give you for their house mustard. It will be strong where the epoxy potted electronics sit, but the tub material above (painted opaque) will be delicate.

I also need to check out PVC conduit end caps, if there are flat ones.

Also, there may be thermosetting caps for lab bottles that will work.

Reply to
Ken C

Interesting!

I'm not real familiar with the mustard tubs. You can test that they are styrene by putting some paint thinner or gasoline on them. They should start dissolving more or less instantly. If so, you should be able to solvent weld nearly anything you want to them or vice versa.

John Aspen Research -

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"Turning Questions into Answers"

Opinions expressed herein are my own and may not represent those of my employer.

Reply to
john.spevacek

But that whole "dissolves in gasoline" nuisance of styrene may preclude it's use in your application's environment (illuminate a motorcycle engine).

R. David Zopf Bomar Specialties Co. (...owes John S. an email. Its coming!)

Reply to
David Zopf

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