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making a TIGHT seal with an o-ring

Posted: Tue Mar 11, 2008 6:37 am
by Rags
Hi.
I Have an old 'stretch monster' toy from the 70's. There are known to leak, from the seal at the neck. I'm replacing the oring seal that pushes the latex onto the flange. And I want to seal it as Tight as possible, to stop the syrup inside the toy from escaping again. I read the the average reccomended stretch for an o-ring is only 5% bigger than its normal size... i think. But i want a very tight seal... so in this case, is it ok to use a much smaller o-ring, and have it stretched to maybe over 100% it original size?
thanks, Rags

Posted: Tue Mar 11, 2008 6:18 pm
by ALDA
Rags,

Over stretching an "o" ring in effect reduces the cross sectional diameter of the ring.

In an engineered joint where an "o" ring is used, the joint clearance is only sealable if the correct size ring is used, stretching will cause joint to leak.
If you use a smaller ring but with a larger cross sectional diameter, you may be lucky and get what you are looking for!

Don't imagine a toy is made to such demanding tolerances, so what have you got to loose.

Give it a try.

ALDA.

Posted: Tue Mar 11, 2008 7:45 pm
by Rags
hmm emailosaid i had a reply... but apparently not....oh well.. im gonna use a small one i think.. and stretch it.. i asked about 4 or 5 diff places... not seen any replys yet...
so i think thats wat im gonna do

Posted: Tue Mar 11, 2008 11:55 pm
by Rags
thanks alda
ill try to get as wide small then
all the best, rags