Best Way to Shrink an O-ring?

I know I've read this before, but don't remember the particulars and my search turned up zilch.

Is the best way to shrink a loose O-ring to simply put it in the fridge for a while? I don't want to make it brittle, so any tips/tricks would be appreciated.

Thanks.

Don't know if it would work, but rubber shrinks when heated, unlike most things.

Geoff

I have never heard of shrinking an 'O' ring - I would suggest getting a new one, plumbing supply, home depot - places like that.

I have a bunch for the different maglites -

Flying Turtle said:

Don't know if it would work, but rubber shrinks when heated, unlike most things.

Geoff

Click to expand...

But the rubber will likely harden when it cools.

most orings arent rubber anyways... good orings are made of nitrile, viton, buna-n and others, these materials are resistant to a lot of chemicals...

As Will said, you better purchase the proper size oring.


Pablo

Thank you, gentlemen, for your replies.

Actually, these are a couple of the o-rings that came installed in my new Lumapower MRV. I probably should just request a couple of spares from Matt at Batteryjunction---he is most helpful on this kind of thing.

Leave it out in the Sun for a few days?

cut a small section out of it and then superglue the ends together
(dont do this if you need to maintain a waterproof seal)

Your best bet is to find one of the quality "old fashioned" hardware stores that stocks everything - take the part that needs the o-ring. Find the right size and maybe pick up a spare too.
IMHO, you would not want to trust any o-ring that has been "shrunk" or changed from the way it was manufactured.

Thank you, gentlemen, for the additional replies.

You can buy o-ring assortments cheaply. There may be some in the assortment that would fit. I suppose the most critical dimension is the thickness.

Here's a cheap kit on eBay. It looks like the one I bought:
http://cgi.ebay.com/407-O-RING-ASSO...2QQihZ017QQcategoryZ42924QQrdZ1QQcmdZViewItem

What he calls OD is what most people call thickness. And what he calls the sizes are what most people call the ID. At least I think that's the deal.

It's confusing because an o-ring has two OD's and one ID. (outer diameter and inner diameter). To make it worse, they are available in metric and English-American sizes.